Apparatus, systems and methods for thermal imaging

Abstract

In one embodiment, the present invention discloses an infrared (IR) imaging system for determining the concentration of a target substance in an object. The imaging system may include an optical system comprising an optical focal plane array (FPA) unit. The optical system may have components defining at least two optical channels, said at least two optical channels being spatially and spectrally distinct from each other. Each of said at least two optical channels may be positioned to redirect IR radiation incident on the optical system toward the optical FPA. The system may include a processing unit containing a processor configured to acquire multispectral optical data representing the target substance from the IR radiation received at the optical FPA. The optical system and the processing unit may be included together in a data acquisition and processing module configured to be worn or carried by a person.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to U.S. Patent Application No. 17 / 241,478, filed April 27, 2021, entitled "Apparatuses, Systems, and Methods for Thermal Imaging," and U.S. Patent Application No. 63 / 042,809, filed June 23, 2020, entitled "Apparatuses, Systems, and Methods for Thermal Imaging," and U.S. Patent Application No. 63 / 022,958, filed May 11, 2020, entitled "Apparatuses, Systems, and Methods for Thermal Imaging." Priority to U.S. Patent Application No. 63 / 019,937 entitled “Apparatuses, Systems, and Methods for Thermal Imaging”, filed May 4, 2020, and priority to U.S. Patent Application No. 63 / 019,929 entitled “Apparatuses, Systems, and Methods for Thermal Imaging”, the contents of which are incorporated herein by reference in their entirety and for all purposes.

[0003] Statement regarding federally sponsored research and development

[0004] Some portions of the technology disclosed in this application were funded by the Energy Advanced Research Projects Agency (ARPA-E) under contract number DE-AR0000541. The government may hold certain rights in these portions of the technology. Technical Field

[0005] The present invention generally relates to a system and method for detecting gas clouds, and more specifically to a system and method for detecting the spectral characteristics of chemical components in an infrared spectral region.

[0006] Related technical descriptions

[0007] Spectral imaging systems and methods have applications in a variety of fields. They acquire spectral images of scenes in one or more regions of the electromagnetic spectrum to detect phenomena, identify material composition, or characterize processes. A spectral image of a scene can be represented as a three-dimensional data cube, where two axes represent two spatial dimensions of the scene and a third axis represents spectral information of the scene in different wavelength regions. Mathematical methods can be used to process this data cube to obtain information about the scene. Some existing spectral imaging systems generate data cubes by scanning the scene in the spatial domain (e.g., by moving a slit across the horizontal dimension of the scene) and / or the spectral domain (e.g., by scanning a wavelength dispersive element to obtain images of the scene in different spectral regions). Such scanning methods acquire only a portion of the complete data cube at a time. These portions of the complete data cube are stored and subsequently processed to generate the complete data cube. Summary of the Invention

[0008] The systems, methods, and apparatus disclosed herein each have several innovative aspects, and no single aspect is solely responsible for the desired properties disclosed herein.

[0009] In one embodiment, the present invention discloses an infrared (IR) imaging system for determining the concentration of a target substance in an object. The imaging system may include an optical system comprising an optical focal plane array (FPA) unit. The optical system may have components defining at least two optical channels, which are spatially and spectrally distinct from each other. Each of the at least two optical channels may be positioned to redirect IR radiation incident on the optical system toward the optical FPA. The system may include a processing unit containing a processor configured to acquire multispectral optical data representing the target substance from the IR radiation received at the optical FPA. The optical system and the processing unit may be included together in a data acquisition and processing module configured to be worn or carried by a person.

[0010] In another embodiment, an infrared (IR) imaging system for determining the concentration of a target substance in an object is disclosed. The imaging system may include an optical system comprising an optical focal plane array (FPA) unit. The optical system may have components defining at least two optical channels, which are spatially and spectrally distinct from each other. Each of the at least two optical channels may be positioned to redirect IR radiation incident on the optical system toward the optical FPA. The system may include a processing unit containing a processor configured to acquire multispectral optical data representing the target substance from the IR radiation received at the optical FPA. The data acquisition and processing module may have a size less than 8 inches × 6 inches × 6 inches.

[0011] In another embodiment, an infrared (IR) imaging system for determining the concentration of a target substance in an object is disclosed. The imaging system may include an optical system comprising an optical focal plane array (FPA) unit. The optical system may have components defining at least two optical channels that are spatially and spectrally distinct from each other. Each of the at least two optical channels may be positioned to redirect IR radiation incident on the optical system toward the optical FPA. The system may include a processing unit containing a processor configured to acquire multispectral optical data representing the target substance from the IR radiation received at the optical FPA. The data acquisition and processing module may have a volume of less than 300 cubic inches.

[0012] In yet another embodiment, a method is disclosed for identifying a target substance or quantifying or characterizing parameters of a target substance in an object. The method may include wearing or carrying a data acquisition and processing module. The data acquisition and processing module may include an optical system and a processing unit in communication with the optical system, which includes an optical focal plane array (FPA) unit. The method may include capturing multispectral infrared (IR) image data at the FPA unit from at least two optical channels that are spatially and spectrally distinct from each other. The method may also include acquiring multispectral optical data representing the target substance from the IR radiation received at the FPA.

[0013] In another embodiment, a system for monitoring the presence of one or more target gases at one or more installation sites is disclosed. The system may include multiple infrared (IR) imaging systems, each including a data acquisition and processing module. The data acquisition and processing module may be configured to capture infrared images of the one or more target gases in real time. The data acquisition and processing module may be configured to associate each captured infrared image with the location of the one or more target gases. The data acquisition and processing module may be configured to transmit the image data associated with the one or more target gases, as well as the location data associated with the location of the one or more target gases, to a central server.

[0014] In yet another embodiment, a method for monitoring the presence of one or more target gases at one or more installation sites is disclosed. The method may include receiving image data from multiple IR imaging systems located at multiple installation sites and configured to be worn or carried by a person. Each IR imaging system may be configured to capture an infrared image of the one or more target gases in real time and associate each captured infrared image with the location of the one or more target gases. The method may include processing the received image data to identify the installation site where the one or more target gases were detected. Details of one or more embodiments of the subject matter described in this disclosure are set forth in the following figures and description. Other features, aspects, and advantages will become apparent from the description, figures, and claims. Note that the relative dimensions in the following figures may not be drawn to scale. Attached Figure Description

[0015] Figure 1 An embodiment of an imaging system is shown, which includes a common front objective lens having a pupil that is spectrally split and re-imaged onto an infrared FPA using multiple lenses.

[0016] Figure 2 An implementation scheme with a segmented front objective and an infrared sensing FPA array is shown.

[0017] Figure 3A This describes an implementation scheme employing a front objective array that is operatively matched to the re-imaging lens array. Figure 3B It shows the relationship with Figure 3A The implementation scheme corresponds to a two-dimensional array of optical components.

[0018] Figure 4 This is a schematic diagram of an implementation scheme employing a field reference array (e.g., a field stop that can be used as a calibration reference) and corresponding relay lens arrays.

[0019] Figure 5A This is a schematic diagram of a 4×3 pupil array including a circular optical filter (and an IR blocking material between the optical filter), the circular optical filter being used for spectral segmentation of the optical wavefront imaged in an embodiment of the system.

[0020] Figure 5B This is a schematic diagram of a 4×3 pupil array including a rectangular optical filter (and an IR blocking material between the optical filters), which is used for spectral segmentation of the optical wavefront imaged by an embodiment of the system.

[0021] Figure 6A Theoretical graphs depict the transmission characteristics of a combination of bandpass filters used in the implementation of the system.

[0022] Figure 6BTheoretical graphs depict the transmission characteristics of the spectral multiplexed notch filter combination used in the system implementation.

[0023] Figure 6C The theoretical curves of the transmission characteristics of the spectral multiplexed long-pass filter combination used in the system implementation are shown.

[0024] Figure 6D The theoretical graph of the transmission characteristics of the spectral multiplexed short-pass filter combination used in the system implementation is shown.

[0025] Figure 7 This is a set of video frames demonstrating the operability of an implementation scheme for a gas detection system.

[0026] Figure 8A and Figure 8B It is a graph showing the dynamic calibration results of the system implementation scheme (on the axis of wavelength in micrometers versus object temperature in degrees Celsius, representing the effective light intensity of the object).

[0027] Figure 9A and Figure 9B Cross-sectional views of different implementations of an imaging system are shown, which includes a reference source and an arrangement of mirrors that can be used for dynamic calibration.

[0028] Figures 10A to 10C A plan view of different implementations of an imaging system is shown, which includes a reference source and an arrangement of mirrors that can be used for dynamic calibration.

[0029] Figure 11A This is a schematic diagram illustrating a mobile infrared imaging system configured to be carried or worn by a human user.

[0030] Figure 11B This is a schematic diagram showing the installation site, which can be monitored by multiple infrared imaging systems.

[0031] Figure 12 This is a schematic system block diagram illustrating a mobile infrared imaging system according to one embodiment.

[0032] Figure 13A This is a schematic system illustration of an optical system according to various embodiments, configured for use in the mobile infrared imaging system disclosed herein.

[0033] Figure 13B This is a schematic system illustration of an optical system according to other embodiments, configured for use in the mobile infrared imaging system disclosed herein.

[0034] Figure 14AThis is a schematic perspective view of a mobile infrared imaging system mounted on a helmet according to various implementation schemes.

[0035] Figure 14B yes Figure 14A An enlarged perspective view of the mobile infrared imaging system shown.

[0036] Figure 14C yes Figures 14A to 14B A perspective cross-sectional view of the mobile infrared imaging system shown.

[0037] Figure 15A It is a schematic perspective view of the system based on various implementation schemes.

[0038] Figure 15B yes Figure 15A A schematic rear perspective view of the system shown.

[0039] Figure 15C It is a schematic front perspective view of the system based on various implementation schemes.

[0040] Figure 15D This is a schematic system illustration of a mobile computing device with a first port according to various embodiments, the first port being configured to be electrically coupled and physically connected to a split aperture infrared spectroscopy imaging (DAISI) system.

[0041] Figure 15E It is a schematic system diagram of a mobile computing device according to various implementation schemes.

[0042] Figure 16A This is a schematic diagram of the DAISI system that can be used according to any implementation scheme disclosed herein.

[0043] Figure 16B This is a schematic front perspective view of the DAISI system according to various implementation schemes, in which the housing has been removed for illustrative purposes only.

[0044] Figure 16C yes Figure 16B A schematic rear perspective view of the DAISI system.

[0045] Figure 16D yes Figure 16B A schematic front perspective view of the optical system of the DAISI system.

[0046] Figure 16E yes Figure 16B A schematic perspective cross-sectional view of the optical system of the DAISI system, in which the shutter is omitted for illustrative purposes.

[0047] Figure 17A It is based on various implementation plans. Figure 16B and Figure 16DThe image shows the front view of the shutter.

[0048] Figure 17B It is a schematic exploded perspective view of the shutter based on some implementation schemes.

[0049] Figure 17C It is in a closed configuration Figure 17B Front view of the shutter.

[0050] Figure 17D It is in an open configuration. Figure 17B and Figure 17C Front view of the shutter.

[0051] Figure 18A and Figure 18B An embodiment of an imaging system according to various embodiments is shown, the imaging system comprising a lens array formed from a monolithic lens substrate.

[0052] Figure 18C An embodiment of an imaging system according to various embodiments is shown, the imaging system comprising a lens array formed of separate lens substrates.

[0053] Figure 18D This is an exploded perspective view of an imaging system, which has a composition of... Figure 18C The lens array is formed by individual lens substrates.

[0054] Figure 18E It is by Figure 18C and Figure 18D A cross-sectional view of a lens assembly formed by a separate lens substrate of the type shown.

[0055] Figure 19 This is a schematic diagram of a patterned array of optical filters that can be used in an imaging system with separate apertures, according to various implementation schemes.

[0056] Figures 20A to 20C The diagram illustrates filter bodies and individual optical filter arrays that can be used in imaging systems with separate apertures, according to various embodiments.

[0057] Figure 21 A schematic system diagram of a mobile infrared imaging system, including one or more optional cooling systems, is shown according to various embodiments.

[0058] Figure 22A This illustrates various implementation schemes. Figure 18D A ray trajectory diagram illustrating an example of optical crosstalk between the optical channels of a lens assembly.

[0059] Figure 22BIt is an exploded perspective view of a lens assembly configured to at least partially reduce optical crosstalk according to various embodiments, which can be used in conjunction with the DAISI system.

[0060] Figure 22C This is a forward schematic diagram of an optical detector according to various implementations, depicting another example of optical crosstalk between adjacent optical channels, and the non-uniformity of the available image size due to crosstalk.

[0061] Figure 22D The illumination area of ​​light transmitted from an object to an optical detector is depicted according to various embodiments, wherein the lens assembly can be configured to increase the usable image area at the optical detector by reducing vignetting.

[0062] Figure 22E This is a front plan view of an exemplary lens assembly, the dimensions of which are configured to transmit radiation to Figure 22D The illuminated area is shown.

[0063] Figure 22F yes Figure 22D An example simulation of intensity roll-off over the available area.

[0064] Figure 22G Exemplary vignetting of scene images according to various implementation schemes is shown.

[0065] Figures 23A to 23D It is a schematic side view of a calorimetric system based on various implementation schemes.

[0066] Figure 24A This is a schematic system diagram of a DAISI system that may include a motion compensation system according to various implementation schemes.

[0067] Figure 24B This is a graph showing a set of exemplary motion thresholds, which can be derived from... Figure 24A The DAISI system is used to activate itself only when the motion of the DAISI system is less than the motion threshold.

[0068] Figure 24C This is a flowchart illustrating exemplary methods for compensating for motion in a DAISI system according to various implementation schemes.

[0069] Figure 24D It is a graph showing the error distribution of the motion compensation system and method described herein according to various implementation schemes.

[0070] Figure 25 This is a perspective view of a thermal imaging system according to some exemplary embodiments described herein.

[0071] Figures 26A to 26D Some exemplary embodiments described herein are depicted. Figure 25 Various views of remote video sensors.

[0072] Figure 26E Depicting Figure 25 Various views of another shape factor of the remote video sensor.

[0073] Figure 26F It shows the relationship with Figure 25 Various views of an exemplary field reference used in thermal imaging systems.

[0074] Figures 26G to 26H Side and top views of an exemplary thermal imaging system implementation with a field reference are shown, respectively.

[0075] Figure 27 Some exemplary embodiments according to the description herein are shown. Figure 25 A schematic block diagram of a video analytics module (including an exemplary circuit system capable of performing various operations).

[0076] Figure 28 An exemplary flowchart for determining target and temperature modifications according to some exemplary embodiments described herein is shown.

[0077] Figure 28A An exemplary flowchart of dynamic calibration of a thermal imaging system is shown.

[0078] Figure 28B An exemplary flowchart of thermal imaging stabilization is shown.

[0079] Figure 29 An exemplary flowchart of facial recognition and target indication identification is shown according to some exemplary embodiments described herein.

[0080] Figures 30A to 30D Exemplary output targets and temperature-modified visible light and IR images are shown according to some exemplary embodiments described herein.

[0081] Figure 31 An exemplary method for determining the compliance of personal protective equipment (“PPE”) according to an exemplary embodiment disclosed herein is illustrated.

[0082] Figure 32 An environment for monitoring user temperature is shown according to an embodiment disclosed herein.

[0083] Figure 33 This is an exemplary flowchart for monitoring the temperature of a user in the environment.

[0084] Figure 34Alternative or additional environments for monitoring user temperature are shown according to embodiments disclosed herein.

[0085] Figure 35 This is yet another exemplary flowchart for monitoring user temperature in the environment.

[0086] Figure 36 An exemplary flowchart for controlling access to the environment is shown.

[0087] In the various figures, similar reference numerals and designations indicate similar elements. Detailed Implementation

[0088] I. Overview of various implementation schemes

[0089] The following description relates to certain embodiments for the purpose of describing the innovative aspects of this disclosure. However, those skilled in the art will readily recognize that the teachings herein can be applied in a variety of different ways. The embodiments described can be implemented in any device, apparatus, or system that can be configured to operate as an imaging system, such as in an infrared imaging system. The methods and systems described herein can be included in or associated with a variety of devices, such as, but not limited to, devices for visible and infrared spectroscopy, multispectral and hyperspectral imaging devices for oil and gas exploration, refining and transportation, agriculture, remote sensing, defense and homeland security, reconnaissance, astronomy, environmental monitoring, etc. The methods and systems described herein have applications in a variety of fields, including but not limited to agriculture, biology, physics, chemistry, defense and homeland security, environment, oil and gas industry, etc. The teachings are not intended to be limited to the embodiments depicted only in the drawings, but have broad applicability as will be apparent to those skilled in the art.

[0090] A spectral image of a scene can be represented as a three-dimensional data cube, where two axes of the cube represent the two spatial dimensions of the scene, and a third axis represents the spectral information of the scene in different wavelength regions. Mathematical methods can be used to process this data cube to obtain information about the scene. Some existing spectral imaging systems generate data cubes by scanning the scene in the spatial domain (e.g., by moving a slit across the horizontal and vertical dimensions of the scene) and / or the spectral domain. Such scanning methods acquire only a portion of the complete data cube at a time. These portions of the complete data cube are stored and subsequently processed to generate the full data cube.

[0091] The various embodiments disclosed herein describe a Distributed Aperture Infrared Spectroscopic Imaging (DAISI) system that is structured and adapted to provide identification of target chemical components of an imaged scene. This system is based on spectrally resolved imaging and can provide such identification using a single scene (also known as a snapshot), which comprises multiple images typically acquired simultaneously with different wavelength compositions. Without loss of generality, a snapshot refers to a system in which most of the data elements collected are continuously observed from the light emitted from the scene. In contrast, in a scanning system, at any given time, only a few data elements are continuously observed from the scene, followed by different sets of data elements, and so on, until a complete dataset is acquired. Relatively fast operation can be achieved in snapshot systems because they do not require the use of spectral or spatial scanning to acquire the infrared (IR) spectral characteristics of the target chemical components. Instead, IR detectors (such as infrared focal plane arrays or FPAs) associated with multiple different optical channels having different wavelength distributions can be used to form a spectral cube of imaging data. Although spectral data can be obtained from a single snapshot comprising multiple simultaneously acquired images corresponding to different wavelength ranges, multiple snapshots are obtained in various embodiments. In various embodiments, these multiple snapshots can be averaged. Similarly, in some embodiments, multiple snapshots can be obtained, and a portion of these snapshots can be selected and possibly averaged. Additionally, the DAISI system does not require cooling compared to commonly used IR spectral imaging systems. Therefore, this allows for the advantageous use of uncooled infrared detectors. For example, in various embodiments, the imaging systems disclosed herein do not include detectors configured to be cooled to temperatures below 300 Kelvin. As another example, in various embodiments, the imaging systems disclosed herein do not include detectors configured to be cooled to temperatures below 273 Kelvin. As yet another example, in various embodiments, the imaging systems disclosed herein do not include detectors configured to be cooled to temperatures below 250 Kelvin. As yet another example, in various embodiments, the imaging systems disclosed herein do not include detectors configured to be cooled to temperatures below 200 Kelvin.

[0092] The embodiments disclosed herein offer several advantages over existing IR spectral imaging systems, most (if not all) of which would require highly sensitive and cooled FPAs to compensate for the reduction in photon flux caused by spectral scanning operations during optical detection. Highly sensitive and cooled FPA systems are expensive and require significant maintenance. Because the various embodiments disclosed herein are configured to operate in a single-acquisition mode without spatial and / or spectral scanning, the instrument can receive photons from multiple points (e.g., each point) of an object substantially simultaneously during a single readout. Therefore, particularly compared to spatial and / or spectral scanning systems, the embodiments of the imaging systems described herein can collect substantially more optical power (e.g., an order of magnitude more photons) from the imaged scene at any given time. Consequently, the various embodiments of the imaging systems disclosed herein can be operated using uncooled detectors (e.g., FPA units comprising microbolometer arrays) that are less sensitive to photons in the IR but are well-suited for continuous monitoring applications. For example, in various embodiments, the imaging systems disclosed herein do not include detectors configured to be cooled to temperatures below 300 Kelvin. As another example, in various embodiments, the imaging systems disclosed herein do not include detectors configured to be cooled to temperatures below 273 Kelvin. As yet another example, in various embodiments, the imaging systems disclosed herein do not include detectors configured to be cooled to temperatures below 250 Kelvin. As yet another example, in various embodiments, the imaging systems disclosed herein do not include detectors configured to be cooled to temperatures below 200 Kelvin. Imaging systems that include uncooled detectors can operate in extreme weather conditions, require less power, can operate both day and night, and are less expensive. Some embodiments described herein are also less susceptible to motion artifacts, which can cause errors in spectral data, spatial data, or both, compared to spatial and / or spectral scanning systems.

[0093] In the various embodiments disclosed herein, the DAISI system can be portable. For example, the DAISI system can be configured to be worn or carried by a person, such as by miniaturizing it to fit within a relatively small housing or compartment. For example, the size and shape of the components of the DAISI system can be configured to fit within a small size, and these components can have a sufficiently small mass to allow a human user to carry or wear the system without excessive force. As explained herein, in some embodiments, the size and shape of the DAISI system can be configured to fit within a volume of less than about 300 cubic inches, or in some embodiments less than about 200 cubic inches. In still other embodiments, the size and shape of the DAISI system can be configured to fit within a volume of less than about 100 cubic inches. For example, in some arrangements, the size and shape of the DAISI system can be configured to fit within a volume ranging from about 50 cubic inches to about 300 cubic inches. In other arrangements, the size and shape of the DAISI system can be configured to fit within a volume ranging from about 80 cubic inches to about 200 cubic inches.

[0094] Advantageously, this portable and / or wearable DAISI system enables users to monitor facilities in remote locations and detect the presence of various gases (e.g., toxic gases) in real time. Furthermore, the portable DAISI system allows users to travel to different facilities to monitor the presence of gases or chemicals in multiple locations. For example, a user could travel to an oil drilling facility extracting oil from underground. The user could carry the portable DAISI system or attach it to their clothing or body (e.g., via clips, hats, etc.) and activate the system upon arrival at the site. The onboard optics of the portable DAISI system can capture one or more snapshot multispectral images of parts of the facility prone to gas or chemical leaks. The onboard computing unit of the portable DAISI system can process the captured multispectral image data to detect and / or classify the gases or chemicals present at the site. A communication module can notify the user of the detected gases. For example, in various implementations, the communication module may send notifications to a user interface (such as a pair of computing glasses, a mobile computing device such as a mobile smartphone, a tablet computing device, a laptop computing device, or any other suitable interface), and the user interface may, for example, display information about the detected gas to the user in real time at an oil drilling facility.

[0095] II. Implementation Plan for a Segmented Aperture Infrared Spectroscopic Imager System

[0096] Figure 1A schematic diagram illustrating the spatial and spectral segmentation of incident light in an embodiment 100 of a Distributed Aperture Infrared Spectroscopic Imager (DAISI) system is provided, which enables imaging of an object 110 having IR spectral characteristics. System 100 includes a front objective lens 124, an optical filter array 130, a re-imaging lens array 128, and a detector array 136. In various embodiments, detector array 136 may include a single FPA or an array of FPAs. Each detector in detector array 136 may be positioned at the focal point of each lens in re-imaging lens array 128. In various embodiments, detector array 136 may include multiple photosensitive devices. In some embodiments, the multiple photosensitive devices may include a two-dimensional imaging sensor array that is sensitive to radiation having wavelengths between 1 μm and 20 μm (e.g., in the near-infrared, mid-infrared, or long-infrared wavelength range). In various embodiments, the multiple photosensitive devices may include CCD or CMOS sensors, calorimeters, microbolometers, or other detectors sensitive to infrared radiation.

[0097] The combination of optical filter array 130 and re-imaging lens array 128 spatially and spectrally segments the aperture of system 100 associated with front objective system 124. In various embodiments, the combination of optical filter array 130 and re-imaging lens array 128 can be considered as forming a spectrally segmented pupil positioned in front of optical detector array 136. The aperture, spatially and spectrally segmented into different aperture portions, forms a plurality of optical channels 120 along which light propagates. In various embodiments, the array 128 of re-imaging lens 128a and the spectral filter array 130 correspond to different optical channels 120, respectively. The plurality of optical channels 120 may be spatially and / or spectrally different. The plurality of optical channels 120 may be formed in object space and / or image space. In one embodiment, the different channels 120 may include optical channels spatially spaced at an angle. The spectral filter array 130 may additionally include a filter-holding aperture shield (including, for example, an IR light-blocking material, such as ceramic, metal, or plastic). Light from object 110 (e.g., a gas cloud) is received by the aperture of system 100. The optical properties of this light in the IR are described by unique absorption, reflection, and / or emission spectra. This light propagates through each of the plurality of optical channels 120 and is further imaged onto an optical detector array 136. In various embodiments, the detector array 136 may include at least one FPA. In various embodiments, each of the re-imaging lenses 128a may be spatially aligned with a corresponding spectral region. In the illustrated embodiment, each filter element from the spectral filter array 130 corresponds to a different spectral region. Each re-imaging lens 128a and the corresponding filter element of the spectral filter array 130 may coincide with (or form a portion of) a segmental aperture and thus coincide with a corresponding spatial channel 120. Therefore, in various embodiments, the imaging lens 128a and the corresponding spectral filter may be positioned in the optical path of one of the plurality of optical channels 120. Radiation from the object 110 propagates through each of the plurality of optical channels 120, travels along the optical path of the corresponding filter element of each re-imaging lens 128a and spectral filter array 130, and is incident on the detector array (e.g., an FPA component) 136 to form a single image (e.g., a sub-image) of the object 110. The image formed by the detector array 136 generally comprises a plurality of sub-images formed by each of the optical channels 120. Each of the plurality of sub-images provides different spatial and spectral information about the object 110. The different spatial information is caused by some parallax due to the different spatial locations of the smaller apertures of the sub-apertures. In various embodiments, adjacent sub-images may be characterized by close or substantially equivalent spectral features. The detector array (e.g., an FPA component) 136 is further operatively connected to a processor 150 (not shown).Processor 150 can be programmed to aggregate data acquired by system 100 into a spectral data cube. The data cube represents, in spatial (x, y) and spectral (λ) coordinates, a global spectral image of object 110 within a spectral region defined by a combination of filter elements in spectral filter array 130. Additionally, in various embodiments, processor or processing electronics 150 can be programmed to determine the unique absorption characteristics of object 110. Furthermore, processor / processing electronics 150 can alternatively or additionally map the global image data cube into a data cube representing, for example, the spatial distribution c of the concentration of a target chemical component within the field of view associated with object 110.

[0098] Various embodiments of implementation 100 may include an optional movable temperature-controlled reference source 160, including, for example, a shutter system having one or more reference shutters maintained at different temperatures. Reference source 160 may include a heater, cooler, or temperature control element configured to maintain reference source 160 at a desired temperature. For example, in various embodiments, implementation 100 may include two reference shutters maintained at different temperatures. Reference source 160 is removably and periodically inserted into the optical path of light traveling along at least one of these channels 120 through system 100 from object 110 to detector array (e.g., FPA component) 136. Thus, the removable reference source 160 can block such an optical path. Furthermore, the reference source 160 can provide a reference IR spectrum for real-time recalibration of various components of system 100, including detector array 136. The configuration of the movable reference source 160 is further discussed below.

[0099] In embodiment 100, the front objective system 124 is shown as including a single front objective lens positioned to establish the common field of view (FOV) of the re-imaging lens 128a and define the aperture stop for the entire system. In this specific case, the aperture stop substantially coincides spatially with the plurality of smaller limiting apertures corresponding to the different optical channels 120, and / or is approximately the same size as or slightly larger than the plurality of smaller limiting apertures. Therefore, the positions of the spectral filters of the different optical channels 120 coincide with the position of the aperture stop for the entire system, which is shown in this example as the surface between the lens system 124 and the array 128 of the re-imaging lens 128a. In various embodiments, the lens system 124 may be an objective lens 124. However, the objective lens 124 is optional, and various embodiments of system 100 do not necessarily include an objective lens 124. In various embodiments, objective lens 124 can slightly shift the images acquired by different detectors in array 136 in space along a direction perpendicular to the optical axis of lens 124, so the function of system 100 is not necessarily affected when objective lens 124 is not included. However, generally speaking, field apertures corresponding to different optical channels can be located in the same or different planes. In some embodiments, these field apertures can be defined by the aperture of re-imaging lens 128a and / or filters in aperture 130. In one embodiment, field apertures corresponding to different optical channels can be located in different planes, and these different planes can be optically conjugate to each other. Similarly, although all filter elements in spectral filter array 130 of embodiment 100 are shown as being located in one plane, generally speaking, different filter elements in spectral filter array 130 can be arranged in different planes. For example, different filter elements in spectral filter array 130 can be arranged in different planes that are optically conjugate to each other. However, in other embodiments, different filter elements can be arranged in non-conjugate planes.

[0100] Compared to implementation 100, the front objective lens 124 does not necessarily have to be a single optical element, but may include multiple lenses 224, such as Figure 2 This is illustrated in embodiment 200 of the DAISI imaging system. These lenses 224 are configured to segment the incident optical wavefront from the object 110. For example, the front objective array 224 may be configured to receive the IR wavefront emitted by the object and directed towards the DAISI system. The plurality of front objectives 224 spatially segment the wavefront into non-overlapping segments. Figure 2 Three objectives 224 in the front optical section of an optical system that contributes to the spatial division of the system's aperture in this example are shown. However, these multiple objectives 224 can be configured as a two-dimensional (2D) lens array. Figure 2 This presents a full view of the imaging system 200 and the resulting field of view of the imaging system 200. (Still...) Figure 2The illustration shows an exploded view 202 of the imaging system 200 in more detail. As shown in detailed view 202, an embodiment of the imaging system 200 includes a field reference 204 at the front end of the system. The field reference 204 can be used to truncate the field of view. Figure 2 The configuration shown is superior to Figure 1 The operational advantage of embodiment 100 is that, due to the smaller objective lens, the overall size and / or weight and / or manufacturing cost of embodiment 200 can be significantly reduced. Each pair of lenses in arrays 224 and 128 is associated with a field of view (FOV). Each pair of lenses in arrays 224 and 128 receives light from the object from a different angle. Therefore, due to parallax, the FOVs of the different pairs of lenses in arrays 224 and 128 do not completely overlap. As the distance between the imaging system 200 (part 202) and the object 110 increases, the overlap area 230 between the FOVs of the individual lenses 224 increases, while the amount of parallax 228 remains approximately the same, thereby reducing its impact on system 200. When the ratio of parallax to object distance is substantially equal to the ratio of pixel size to system focal length, the parallax effect can be considered negligible and is practically no longer distinguishable. Although lenses 224 are shown as being substantially arranged in the same plane, optional different objectives in the front objective lens array 224 can be arranged in more than one plane. For example, some individual lenses 224 may be displaced relative to some other individual lenses 224 along axis 226 (not shown), and / or have a different focal length compared to some other lenses 224. As discussed below, field reference 204 can be used to calibrate multiple detectors 236.

[0101] In one embodiment, the front objective system, such as lens array 224, is configured as a lens array integrated or molded in association with a monolithic substrate. This arrangement reduces the cost and complexity that would otherwise accompany the optical adjustment of individual lenses within the system. Individual lenses 224 may optionally include lenses with varying magnification. As an example, a pair of thin, large-diameter Alvarez plates may be used in at least a portion of the front objective system. Without loss of generality, the Alvarez plates can produce a focal length change when orthogonally translated relative to the beam.

[0102] Further reference Figure 1A detector array 136 (e.g., an FPA component) configured to receive optical data representing one or more spectral features of the imaged object 110 can be configured as a single imaging array (e.g., an FPA) 136. This single array may be adapted to simultaneously acquire more than one image (formed by more than one optical channel 120). Alternatively, the detector array 136 may include an FPA unit. In various embodiments, the FPA unit may include multiple optical FPAs. At least one of these multiple FPAs may be configured to acquire more than one spectrally different image of the imaged object. For example, as... Figure 2 As shown in embodiment 200, in various embodiments, the number of FPAs included in the FPA unit may correspond to the number of front objectives 224. Figure 2 In embodiment 200, for example, three FPAs 236 corresponding to three objectives 224 are provided. In one embodiment of the system, the FPA unit may include a microbolometer array. The use of multiple microbolometers advantageously allows for an increase in the total number of detection elements (i.e., pixels) for recording a three-dimensional data cube in a single acquisition event (i.e., a snapshot) in a cost-effective manner. In various embodiments, the microbolometer array utilizes the detector pixels of the FPA array (e.g., each FPA) more efficiently because it reduces, minimizes, and / or eliminates the number of unused pixels that may exist between images when using a single microbolometer.

[0103] Figure 3A An embodiment 300 of the imaging system is schematically illustrated, wherein the number of front objectives 324a in lens array 324, the number of re-imaging lenses 128a in lens array 128, and the number of FPAs 336 are equal. In this configuration, each combination of the corresponding front objectives 324, re-imaging lenses 128a, and FPAs 336 constitutes a separate imaging channel. This channel is associated with the acquisition of IR light transmitted from object 110 through individual filter elements of optical filter array 130. The field reference 338 of system 300 is configured to have a uniform temperature across its surface and is characterized by a predetermined spectral profile of the radiation emitted from it. In various embodiments, the field reference 338 can be used as a calibration target to aid in calibrating the FPA or to maintain the calibration of the FPA. Therefore, in various embodiments, the field reference 338 is used to dynamically adjust the data output from each FPA 336 after light is acquired from object 110. This dynamic calibration process helps to provide the correct acquisition data for different (e.g., most or every) FPA 336 output representations relative to other FPA 336s used for analysis, as discussed in more detail below.

[0104] Figure 3B It shows the relationship with Figure 3AThe illustrated imaging system implementation scheme 300 is shown in a plan view perpendicular to axis 226. For Figure 3B In one embodiment, the optical components (e.g., objective lens 324a, filter elements of the spectral filter array 130, re-imaging lens 128a, and FPA unit 336) are arranged in a 4×3 array. In one embodiment, the 4×3 array 340 of the optical components (lenses 324a, 128a; detector element 336) is used behind the temperature-controlled reference target 160. The field reference aperture 338 may be adapted to shield and / or block the peripheral portion of the light beam propagating from the object 110 toward the FPA unit 336. Thus, the field reference 338 shields and / or blocks one or more boundaries or peripheral portions of the image of the object 110 formed on the FPA element positioned along the perimeter 346 of the detector system. Generally, when two elements of the FPA unit are used to observe the same portion of a scene in the same spectral region using the same optical components, the two elements will produce substantially equal digital count values. If any of these input parameters (e.g., the scene to be observed, the spectral content of light from the scene, or the optical elements that deliver light from the scene to the two detector elements) are different, the counts associated with the elements of the FPA unit will also be different. Therefore, as an example, in the two FPAs of FPA unit 336 (such as...) Figure 3B Those (represented as #6 and #7) can be dynamically modulated to the output from one of the FPAs (such as FPA element #2 or FPA element #11, which handles light with similar spectral characteristics) while remaining substantially unobstructed by the field reference 338.

[0105] Figure 4A portion of another embodiment of an imaging system 400 comprising an array 424 of front objectives 424a is schematically shown. The array 424 of lenses 424a is adapted to receive light from an object 110 and relays the received light to an array 128 of re-imaging lenses 128a via an array 438 of field references (or field stops) 438a and an array 440 of relay lenses. The spectral characteristics of the field references / field stops 438a are known. The field references 438a are disposed on corresponding intermediate image planes defined by the respective corresponding front objectives 424a relative to the object 110. All field references 438a are disposed in the same plane when the refractive characteristics of all front objectives 424a are substantially the same. The field references 438A of the array 438 shield the peripheral region of the image formed at the detector plane 444 (or project shadows thereon) via the respective corresponding spatial imaging channels 450 of the system 400 before the processor 150 performs spectral processing on the corresponding image (e.g., a sub-image). The array 440 of relay lenses then transmits light along each imaging channel in the imaging channel 450, through different spectral filters 454a of the filter array 454, through a calibration device including two temperature-controlled shutters 460a, 460b, and then to the detector module 456. In various embodiments, the detector module 456 may include a microbolometer array or some other IR FPA.

[0106] Implementation 400 offers several operational advantages. It is configured to provide a spectrally known object within each image (e.g., a sub-image) and for each snapshot acquisition, which can be calibrated for the snapshot acquisition. This spectral determinism is advantageous when using an array of IR FPAs such as microbolometers, whose detection characteristics can change from one imaging frame to the next due in part to variations in the imaged scene and thermal effects caused by adjacent FPAs. In various implementations, the field reference array 438 of implementation 400 can be positioned within the Rayleigh range (approximately corresponding to the depth of focus) associated with the front objective lens 424, thereby removing unusable blurred pixels due to the field reference being outside this range. Additionally, Figure 4 The implementation scheme 400 can be compared to, for example Figure 3A The configuration 300 is more compact. For example, in Figure 3A In the system shown, the field reference 338 can be separated from the lens array 324 by a distance greater than a few (e.g., five) focal lengths to minimize / reduce the blurring contributed by the field reference to the image formed at the detector plane.

[0107] In various implementations, the multi-optical FPA unit of the IR imaging system may additionally include an FPA configured to operate in the visible light portion of the spectrum. (Reference) Figure 1For example, an image of a scene of interest formed by such a visible-light FPA can be used as a background to form a composite image by overlaying the IR image with the visible-light image. Using a processor and a specially designed computer program capable of performing this data processing, the IR images can be virtually overlaid, or actually overlaid by the observer. IR images can be created based on image data acquired by each FPA 136. The composite image thus formed facilitates the identification of the precise spatial location of the target substance, and the system is able to detect / identify the spectral characteristics of that target substance.

[0108] Optical filters .

[0109] Optical filters for defining IR images (e.g., sub-images) of a specific object, used in conjunction with the system implementation, can employ absorption filters, interference filters, and Fabry-Perotetalon-based filters, to name just a few. When using an interference filter, the optical filter is obtained by using a separate re-imaging lens (such as...) Figure 1 , Figure 2 Figure 3 and Figure 4 Image acquisition of the individual imaging channel defined by lens 128a) can be performed in a single spectral bandwidth or multiple spectral bandwidths. (See again...) Figures 1 to 4 The implementation schemes 100, 200, 300, and 400, and further reference... Figure 3B , Figure 5A and Figure 5B An example of a 4×3 array of spectral filters 130 is shown. Individual optical filters 1 to 12 are juxtaposed with supporting optomechanical elements (not shown) to define a filter array plane that is substantially perpendicular to the total optical axis 226 of the imaging system during operation. In various embodiments, the individual optical filters 1 to 12 need not be discrete optical components. Instead, the individual optical filters 1 to 12 may include one or more coatings applied to a re-imaging lens (such as...). Figure 1 , Figure 2 Figure 3 and Figure 4 One or more surfaces of the lens 128a) or the surface of one or more detectors.

[0110] The optical filtering configurations of the various embodiments disclosed herein can advantageously utilize bandpass filters that define specific spectral bands. For example, their transmission curves can be used in... Figure 6A Any of the filters 0a to 3a shown. The filter can be placed in front of the optical FPA (or typically between the optical FPA and the object). See further reference, in particular. Figure 1 , Figure 2 Figure 3 and Figure 4When the optical detector arrays 136, 236, 336, and 456 include microbolometers, the main contribution to the noise associated with image acquisition is caused by detector noise. To compensate for and / or reduce noise, the various embodiments disclosed herein utilize spectral multiplexing filters. In various embodiments, the spectral multiplexing filters may include multiple long-pass filters, multiple band-pass filters, and any combination thereof. Figure 6B Examples of spectral transmission characteristics of filters 0b to 3d for various embodiments of the imaging system disclosed herein for spectral multiplexing are depicted. Figure 6C The filter can be referred to as a long-pass LP filter. LP filters typically attenuate shorter wavelengths and transmit (through) longer wavelengths (e.g., within the effective range of the target IR portion of the spectrum). In various embodiments, short-pass filters SP filters can also be used. SP filters typically attenuate longer wavelengths and transmit (through) shorter wavelengths (e.g., within the effective range of the target IR portion of the spectrum). At least in part due to the snapshot / non-scanning operation mode, the embodiments of the imaging system described herein can use a less sensitive microbolometer without compromising SNR. Using a microbolometer as a detector noise limiting device not only benefits from the use of filters for spectral multiplexing but also eliminates the need for cooling the imaging system during normal operation.

[0111] Refer again Figure 6A , Figure 6B , Figure 6C and Figure 6D Compared to filters (0a…3a), each filter in the filters (0b…3d) transmits light over a substantially wider region of the electromagnetic spectrum. Therefore, when a set of spectrally multiplexed filters (0b…0d) is used with an imaging system implementation, the total amount of light received by the FPA (e.g., 236, 336) is greater than the total amount of light received when using bandpass filters (0a…4a). This “increased” light transmission, defined by using spectrally multiplexed LP (or SP) filters, facilitates increasing the signal on the FPA above the detector noise level. Furthermore, in one implementation of the imaging system, by using filters with a spectral bandwidth greater than that of the bandpass filters, the uncooled FPA of the imaging system implementation experiences less heating from radiation incident on it from the imaging scene and from radiation emitted by the FPA itself. This reduced heating is due to a reduction in back-reflected thermal radiation from the FPA and from the non-bandpass regions reflecting off the filters. This parasitic effect is reduced due to the wider transmission region of the multiplexed LP (or SP) filters, thereby improving the overall performance of the FPA unit.

[0112] In one implementation, LP and SP filters can be combined in a spectral multiplexing manner to increase or maximize the spectral range of the transmission region of the filter system of the embodiment.

[0113] Based on the following derivation, the advantages of using spectral multiplexing filters can be understood, where a system with M filters is examined (however, it is understood that in practice, embodiments of the invention can employ any number of filters). As an illustrative example, consider the case where M = 7. The analysis given below pertains to a spatial location in each of the images (e.g., sub-images) formed by different imaging channels (e.g., different optical channels 120) in the system. A similar analysis can be performed for each point in the image (e.g., sub-image), and therefore the analysis can be appropriately extended as needed.

[0114] The unknown quantity of light in each of the M spectral channels (corresponding to these M filters) is represented by f1, f2, f3, f3…f M This indicates that the readings from the corresponding detector elements receiving the light transmitted by each filter are represented by g1, g2, g3…g M This indicates that the measurement error is denoted by n1, n2, n3…n M The readings at the seven FPA pixels can then be represented by the following formula, where each FPA pixel is represented by... Figure 6A Corresponding bandpass filter optical filtering:

[0115] g1 = f1 + n1,

[0116] g2 = f2 + n2,

[0117] g3 = f3 + n3,

[0118] g4 = f4 + n4

[0119] g5 = f5 + n5,

[0120] g6 = f6 + n6,

[0121] g7 = f7 + n7,

[0122] These readings (pixel measurement results) g i It is the spectral intensity f i The estimated value. Due to measurement error n i The estimated value g i Not equal to the corresponding f i However, if the measurement noise distribution has zero mean, the overall average of each individual measurement can be considered equal to the true value, i.e. <g i >=f iHere, angle brackets indicate the operation of calculating the population mean of a random variable. Therefore, the variance of the measurement results can be expressed as:

[0123]

[0124] In implementations utilizing spectral multiplexing filters, the amount of radiant energy transmitted towards a given detector element by each filter in the LP or SP filters of the spectral multiplexing can exceed the radiant energy transmitted through the spectral bands of the bandpass filter, compared to implementations utilizing bandpass filters. In this case, the light intensity corresponding to the individual spectral bands can be reconstructed through computation. Such implementations can be referred to as "multiplexing designs".

[0125] A matrix of such "multiplexed filter" measurement results includes a Hadamard matrix requiring a "negative" filter, which may not necessarily be suitable for the optical implementation disclosed herein. In various implementations, the S-matrix method (which is limited to a number of filters equal to an integer multiple of four minus one) or a row-doubling Hadamard matrix (requiring the number of filters to be an integer multiple of 8) can be used. Here, the possible number of filters set using the S-matrix is ​​3, 7, 11, etc., and if a row-doubling Hadamard matrix is ​​used, the possible number of filters is 8, 16, 24, etc. For example, the target of the measurement could be to use the following seven measurement results g i To measure the intensity f of seven spectral bands i :

[0126] g1 = f1 + 0 + f3 + 0 + f5 + 0 + f7 + n1,

[0127] g2=0+f2+f3+0+0+f6+f7+n2

[0128] g3 = f1 + f2 + 0 + 0 + f5 + 0 + f7 + n3

[0129] g4 = 0 + 0 + 0 + f4 + f5 + f7 + f8 + n4

[0130] g5 = f1 + 0 + f3 + f4 + 0 + f6 + 0 + n5

[0131] g6 = 0 + f2 + f3 + f4 + f5 + 0 + 0 + n6

[0132] g7 = f1 + f2 + 0 + f4 + 0 + 0 + f7 + n7

[0133] Figure 6B The optical transmission characteristics of the aforementioned filter are described in [the text]. Here, [the text will not be described using methods similar to...]. <g i >=f iThe relationship provides for f i A direct estimate. Conversely, if the "hat" notation is used to denote an estimate of a given value, a linear combination of measurements can be used, for example,

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141] When n i When it is a zero-mean random variable, these It is an unbiased estimate, therefore The measurement variance corresponding to the i-th measurement is given by the following formula:

[0142]

[0143] As can be seen from the above equation, by employing a spectral multiplexing system, the signal-to-noise ratio (SNR) of the measurement results is improved by a factor of [missing information].

[0144] For N channels, the SNR improvement achieved using a spectral multiplexing system can be expressed as: For example, an implementation using 12 spectral channels (N=12) is characterized by an improvement in SNR compared to non-spectral multiplexing systems, including a factor of up to 1.88.

[0145] exist Figure 6C and Figure 6D Two additional examples of filter arrangements 0c to 3c and 0d to 3d for correlation spectral multiplexing, respectively, are shown in various implementations of the imaging system described herein. Figure 6C and Figure 6D The spectral multiplexing filter shown can be used in implementations of imaging systems employing uncooled FPAs (such as microbolometers). Figure 6CA set of long-pass (LP) filters for spectral multiplexing used in the system is shown. LP filters typically attenuate shorter wavelengths and transmit (pass through) longer wavelengths (e.g., within the effective range of the target IR portion of the spectrum). Using an embodiment of the system described herein, a single spectral channel having transmission characteristics corresponding to the differences between the spectral transmission profiles of at least two of these LP filters can be used to acquire imaging data of a data cube. In various embodiments, the spectral filters can have different spectral characteristics relative to different FPA settings. In various embodiments, the spectral filters can be positioned in front of only some of the FPAs, while the remaining FPAs can be configured to receive unfiltered light. For example, in some embodiments, only nine of the twelve detectors in the aforementioned 4×3 detector array can be associated with spectral filters, while the other three detectors can be configured to receive unfiltered light. Such a system can be configured to acquire spectral data in 10 different spectral channels in a single data acquisition event.

[0146] Using a microbolometer as the detector noise limiting device not only benefits from the use of spectral multiplexing filters but also eliminates the need for cooling the imaging system during normal operation. Compared to imaging systems that include highly sensitive FPA units with reduced noise characteristics, the implementation of the imaging system described herein can employ a less sensitive microbolometer without compromising SNR. This result is at least in part due to the snapshot / non-scanning operation mode.

[0147] As described above, in addition to the temperature control reference unit (e.g., temperature-controlled shutters such as shutters 160, 460a, 460b), the implementation may optionally employ a field reference component (e.g., Figure 3A The field reference aperture 338) or field reference component array (e.g., Figure 4 The field reference aperture (438) in the data cube enables dynamic calibration. This type of dynamic calibration can be used for spectral acquisition of one or more data cubes or for each data cube. It can also be used for spectrally neutral camera-to-camera combinations to achieve dynamic compensation for parallax artifacts. The use of a temperature-controlled reference unit (e.g., a temperature-controlled shutter system 160) and a field reference component facilitates maintaining correct calibration of each individual FPA and the entire FPA unit as a whole.

[0148] In particular, further reference Figure 1 , Figure 2 Figure 3 and Figure 4The temperature control unit typically employs a system with a first temperature zone and a second temperature zone maintained at different first and second temperatures. For example, the shutter system of each embodiment in embodiments 100, 200, 300, and 400 may employ not one but at least two temperature-controlled shutters, which are substantially parallel to each other and transverse to the total optical axis 226 of embodiments 100, 200, 300, and 400. Two shutters at two different temperatures can be used to provide more information for calibration; for example, the absolute value of the difference between FPAs at a temperature and how that difference changes with temperature can be recorded. For example, reference... Figure 4 This illustrates a multi-shutter configuration where the use of multiple shutters allows the user to create a known reference temperature difference sensed by the FPA 456. This reference temperature difference is provided by the IR radiation emitted by these shutters when shutters 460a, 460b are positioned to block radiation from object 110. Therefore, not only can the offset value corresponding to each EPA pixel in the individual FPA pixel be adjusted, but also the gain value of these FPAs can be adjusted. In an alternative embodiment, the system having a first temperature zone and a second temperature zone may include a single component or multiple components. This single component or multiple components may include, for example, a plate. This component can be mechanically moved across the optical axis using suitable guides and has a first portion at the first temperature and a second portion at the second temperature.

[0149] In practice, the calibration process of the imaging system implementation begins by estimating gain and offset by performing measurements on radiation emitted independently from at least two temperature-controlled shutters with known and different emissivities. Gain and offset can vary depending on the detector pixels. Specifically, the response of detector unit 456 to radiation emitted from one shutter is first performed. For example, a first shutter 460a blocks the field of view (FOV) of detector 456, and temperature T1 is measured directly and independently using a thermistor. After such initial measurements, the first shutter 460a is removed from the optical path of light passing through this implementation, and a second shutter (e.g., 460b) is inserted into its position across optical axis 226 to prevent light from propagating through the system. The temperature of the second shutter 460b can differ from that of the first shutter (T2 ≠ T1). The temperature of the second shutter 460b is also measured independently using a thermistor placed in contact with the shutter, and the detector's response to radiation emitted from shutter 460b is also recorded. The FPA pixels (represented in digits, or "counted") are compared to the radiation source L. i The operation response is represented as g i The readings corresponding to the measurement results of the two shutter speeds can be expressed as:

[0150] g1=γL1(T1)+g offset

[0151] g2=γL2(T2)+g offset

[0152] Here, g offset γ is the pixel offset value (in counts), and γ is the pixel gain value (in counts per radiating unit). If the values ​​of g1 and g2, as well as the radiating values ​​L1 and L2, are available, then these two formulas can be obtained with respect to the two unknowns g. offset The solutions for γ. For example, these values ​​can be measured by reference instruments or calculated based on known temperatures T1 and T2 and the known spectral responses of the optical system and FPA. For any subsequent measurement, the above formula can be reversed to estimate the radiance of the object from the detector measurements, and this can be done for each pixel in each FPA within the system.

[0153] As already discussed, and with reference to Figures 1 to 4 The field reference aperture can be positioned in the object space or image space of the optical system, and its size is designed to block a specific portion of the IR radiation received from the object. In various embodiments, the shape of the opening of the field reference aperture can substantially resemble the boundary of the filter array (e.g., and refer to...). Figure 3B , Figure 5B The filter array (e.g., rectangular). The field reference aperture can be placed at least several times (at least five times in one embodiment) the distance from the lens focal length in front of the objective lens (124, 224, 324, 424), thus placing the field reference aperture closer to the object. Placing the field reference aperture closer to the object reduces image blur. Figure 4 In implementation scheme 400, the field reference aperture can be placed within the depth of focus of the image conjugate plane formed by the front objective lens 424. Typically, the field reference facilitates, completes, and / or enables dynamic compensation in the system by referencing and stabilizing the outputs from different FPGAs in the array by providing spectrally known and time-stable objects within each scene.

[0154] Since the offset value of each FPA is typically adjusted by hardware from one frame to the next, comparing the output of one FPA with the output of another FPA can introduce errors that are not, for example, established by the static calibration parameter g of the movable shutter 160. offset And compensated by γ. To ensure that the FPA operates in a radiometrically consistent manner over time, for a portion of each detector array, a reference source (such as...) is observed on multiple frames acquired over time. Figure 3AThe field reference (338) is advantageous. If the spectrum of the reference source is known a priori (such as a blackbody source at a known temperature), the response of each FPA to the reference source can be measured to estimate the change in pixel offset value. However, it is not necessary to know the temperature of the reference source. In such embodiments, dynamic calibration of the different detectors can be performed by monitoring the changes in the gain and offset of the individual detectors from when the movable shutter used for static calibration is removed. An exemplary calculation of the dynamic offset is performed as follows.

[0155] In the implementation of the imaging system, one FPA in the FPA array can be selected as the "reference FPA". The field reference temperature measured by all other FPAs can be adjusted to match the field reference temperature measured by the reference discussed below. The image obtained from each FPA consists of a set of pixels occluded by the field reference 338. The calibration parameter g obtained earlier is used. offset And γ (pixel offset and gain), the effective blackbody temperature T of the field reference measured by each FPA is estimated using the following formula. i :

[0156] T i =mean{(g+Δg)} i +g offset / γ}=mean{(gg offset ) / γ}+ΔT i

[0157] Using the formula above, obtain the average value of all pixels occluded by the field reference. In the formula above, Δg i It is the offset value of the current frame and the Δg obtained during the calibration step. offset The difference. For the baseline FPA, Δg i It can be simply set to zero. Then, using the temperature difference measured by each FPA, we can obtain:

[0158] T i -T ref =mean{(g+Δg)} i +g offset / γ}+ΔT i -mean{(gg offset ) / γ}=ΔT i

[0159] Once the ΔT for each FPA is measured i This allows the value to be subtracted from each image, thus forcing consistency in operation between this type of FPA and the reference FPA. While the calibration procedure has been discussed above with reference to temperature calibration, a similar procedural calibration method can also be implemented relative to radiation values.

[0160] Examples of measurement methods .

[0161] Before performing optical data acquisition using an implementation of an IR imaging system as described herein, one or more, most, or potentially all FPAs of the system can be calibrated. For example, greater than 50%, 60%, 70%, 80%, or 90% of FPAs 336 can be initially calibrated. Figure 3A As shown, these FPAs 336 can form individual images of an object using light delivered in corresponding optical channels, which may include a combination of a corresponding front objective lens 324 and a re-imaging lens 128. The calibration process allows for the formation of individual images in equivalent units (making it possible, for example, to recalculate readings from FPA pixels in units such as temperature or radiation). Furthermore, the calibration process can also allow FPAs (e.g., each of the FPAs) to be spatially co-registered with each other, such that a given pixel of a particular FPA can be optically remapped by the optical system to the same location on the object as the corresponding pixel of another FPA.

[0162] To achieve at least some of these objectives, a spectral difference method can be employed. This method involves forming a difference image from various combinations of images from different channels. Specifically, the images used to form the difference image can be registered with two or more different FPAs in spectrally different channels, which are different spectral filters with different spectral characteristics. Images from different channels with different spectral characteristics will provide different spectral information. Therefore, comparing (e.g., subtracting) these images can produce valuable spectral-based information. For example, if a filter element in spectral filter array 130 corresponding to a particular FPA 336 transmits light from an object 110 including a gas cloud, for example, having a specific spectrum containing gas absorption peaks or gas emission peaks, while another filter element in spectral filter array 130 corresponding to another FPA 336 does not transmit such a spectrum, then the difference between the images formed by the two FPAs in question will highlight the presence of gas in the difference image.

[0163] A drawback of spectral difference methods is that contributions from auxiliary features associated with imaging (not just the target material itself, such as the gas) can also be highlighted in the difference image and contribute to its appearance. To name just a few examples, such contributions include imaging caused by parallax at object edges, the effect of magnification differences between two or more optical channels, and differences in rotational positioning and orientation between FPAs. While errors related to magnification and those caused by FPA rotation can be compensated for by improving the accuracy of the instrument construction and by post-processing the acquired images, parallax is scene-dependent and not easily corrected. Furthermore, spectral difference methods are susceptible to radiometric calibration errors. Specifically, if one FPA records the light radiation from a given feature of an object as, for example, a temperature of 40°C, while data from another FPA represents the same feature as 39°C, such features will be enhanced or highlighted in the difference image (which is formed at least in part based on images provided by both FPAs) due to this radiometric calibration error.

[0164] One solution to some of these problems is to compare (e.g., subtract) images obtained at different times from the same FPA. For example, an image can be compared to or subtracted from a reference image obtained at another time. Such a reference image, subtracted from other images obtained later, can be referred to as a time reference image. This solution can also be applied to spectral difference images. For example, image data generated from a spectral difference image can be normalized by data corresponding to a time reference image. For example, a time reference image can be subtracted from a spectral difference image to obtain a time difference image. For the purposes of this disclosure, this process is referred to as a time difference algorithm or method, and the image obtained by subtracting a time reference image from another image (such as a spectral difference image) is referred to as a time difference image. In some embodiments employing spectral difference, for example, a time reference image can be formed by creating a spectral difference image from two or more images registered by two or more FPAs at a single time. This spectral difference image is then used as the time reference image. The time reference image can then be subtracted from other images obtained later to provide normalization, which is useful for subtracting or removing various errors or harmful effects. For example, the algorithm's results are unaffected by prior knowledge of whether an object or scene contains a target substance (such as a gas of interest), as the algorithm can highlight variations in scene characteristics. Therefore, as described above, based on snapshot image acquisition at any later time, a spectral difference image can be calculated from multiple spectral channels, and the spectral difference image can be subtracted from the time reference image to form a time difference image. Thus, this time difference image is a normalized difference image. The difference between two images (the time difference image) can highlight the target substance (gas) within the normalized difference image, since this substance is not present in the time reference frame. In various implementations, more than two FPAs can be used to register both the time reference image and the later acquired difference image to obtain a better SNR quality factor. For example, if two FPAs are associated with spectral filters having the same spectral characteristics, the images obtained from these two FPAs can be combined after they are registered to obtain a better SNR factor.

[0165] While temporal difference methods can be used to reduce or eliminate some of the drawbacks of spectral difference methods, they inherently introduce undesirable problems. For example, temporal difference of imaging data is less sensitive to errors caused by calibration and parallax than spectral difference of imaging data. However, any changes in the imaging scene that are not related to the target substance of interest (such as a specific gas) are highlighted in the temporal difference image. Therefore, such changes in the imaging scene can be mistakenly perceived as the location of the target substance, triggering errors in target substance detection. For example, if the temperature of the background of the detected gas changes (due to natural cooling during the day, or due to an increase in the FOV of a person, animal, or other object passing through the IR imaging system), such temperature changes produce a signal difference compared to measurements taken at earlier times. Thus, the cause of the scene temperature change (cooled object, walking person, etc.) can appear as the detected target substance (such as a gas). Therefore, it is concluded that attempting to compensate for operational differences between the individual FPAs of a multi-FPA IR imaging system by using spectral or temporal difference methods can introduce additional problems leading to erroneous detection of the target substance. These problems include detection errors caused by scene motion and errors caused by parallax, which are not easily corrected and / or compensated. Therefore, it is necessary to compensate for image data acquisition and processing errors caused by the motion of elements within the imaged scene. Various implementation schemes of the data processing algorithms described in this paper address and satisfy the need to compensate for image detection errors caused by such motion and parallax.

[0166] In particular, to reduce or minimize the difference caused by parallax between images generated using two or more predetermined FPAs, the parallax effect can be estimated using another difference image formed by images from at least two different FPAs. Parallax error can be determined by comparing images from two different FPAs, where the positions between the FPAs are known. Parallax can be calculated based on the known relative positional difference. The difference between images from these two FPAs can be attributed to parallax, especially if the FPAs have the same spectral characteristics, such as having the same spectral filter, or if neither has a spectral filter. However, parallax error correction can still be obtained from two FPAs with different spectral characteristics or spectral filters, especially if the different spectral characteristics (e.g., the transmission spectra of the corresponding filters) are known and / or negligible. Using more than two FPAs or FPAs at different locations, such as FPAs spaced further apart, can be useful. For example, when using images from the outermost two cameras in an array (such as those corresponding to…)… Figure 5A When performing spectral differencing of image data by collecting the differences between images from filters 2 and 3 of the filter array (FPA), a difference image known as "difference image 2-3" is formed. In this case, alternative "difference images 1-4" are further formed, for example, by the images corresponding to the filter array (FPA). Figure 5AImage data acquired by alternative FPAs of filters 1 and 4 are formed. Assuming or ensuring that both alternative FPAs have approximately the same spectral sensitivity to the target substance, the alternative "difference images 1-4" will highlight pixels corresponding to features caused by parallax in the image. Therefore, based on the certainty that the same pixels are highlighted in the spectral "difference images 2-3" used for target substance detection, it can be concluded that the image features corresponding to these pixels are likely caused by parallax, rather than by the presence of the target substance in the imaging scene. It should be noted that when using a single FPA or multiple FPAs as described above, parallax compensation can also be performed using images created by individual re-imaging lenses 128a. FPAs spaced apart from each other in different directions are also useful. More than two, such as three or four or more FPAs, can be used to establish parallax for parallax correction. In some embodiments, two central FPAs and one corner FPA are used for parallax correction. In some embodiments, these FPAs may have substantially similar or identical spectral characteristics, for example, filters with similar or identical transmission spectra, or no filters at all.

[0167] Another capability of the implementation described herein is the ability to perform volume estimation of the gas cloud. This can be achieved by using (rather than compensating for or negating) the effects caused by parallax described above. In this case, the measured parallax between two or more similar spectral response images (e.g., two or more channels or FPAs) can be used to estimate the distance between the imaging system and the gas cloud, or the distance between the imaging system and an object in the system's field of view. The lateral image offset d caused by the parallax between two images is related to the distance z between the cloud or object 110 and the imaging system, according to the formula z = -sz' / d. Here, s is the interval between the two similar spectral response images, and z' is the distance from the rear lens to the image plane. The value of z' is typically approximately equal to the focal length f of the lens of the imaging system. Once the distance z between the cloud and the imaging system is calculated, the size of the gas cloud can be determined based on the magnification, m = f / z, where each image pixel Δx' on the gas cloud corresponds to the physical size Δx = Δx' / m in the object space. To estimate the volume of the gas cloud, a specific symmetry of the cloud thickness based on the physical size of the cloud can be assumed. For example, cloud images can be rotated around a central axis passing through the cloud image to create a three-dimensional volumetric estimate of the cloud size. It is noteworthy that, in the implementation described herein, such volumetric estimation requires only a single imaging system. In fact, due to the fact that information about the angle at which the system sees the cloud is decoded in the parallax effect, the image data includes information about the imaging scene observed by the system in relation to at least two angles.

[0168] When using temporal difference algorithms to process acquired imaging data, scene variations not caused by the target material may be unintentionally highlighted in the resulting image. In various implementations, compensation for this error utilizes temporal difference between two field-aperture cameras (FPAs) that are substantially equally spectrally sensitive to the target material. In this case, the temporal difference image will highlight those pixels whose intensity has changed over time (rather than wavelength). Therefore, subtracting the data corresponding to these pixels on the two FPAs to form the resulting image excludes the contribution of the target material to the resulting image, where the two FPAs are substantially equally spectrally sensitive to the target material. Thus, scene variations (i) caused by the presence of the target material and (ii) caused by background variations unrelated to the target material can be distinguished. In some implementations, the two channels having the same or substantially similar spectral responses to be substantially equally spectrally sensitive to the target material may include FPAs operating using visible light. It should also be noted that data acquired using visible light FPAs (when present as part of an additional IR imaging system) can also be used to facilitate such distinction and compensation for motion-induced imaging errors. The noise figure of a visible light camera is typically much lower than that of an IR camera (at least during the daytime). Therefore, temporal difference images obtained using image data from a visible light FPA can be very accurate. A visible light FPA can be used to compensate for motion in a system, as well as many potential false alarms caused by motion in a scene due to people, vehicles, birds, and steam, provided the moving object is observable within the visible light region of the spectrum. This has the added benefit of providing an additional level of false alarm suppression without reducing system sensitivity, since many targets (such as gas clouds) are not observable within the visible spectral region. In various implementations, an IR camera can be used to compensate for motion artifacts.

[0169] Another method for gas detection is to use spectral unmixing. Spectral unmixing assumes that the spectrum measured at a detector pixel consists of the sum of component spectra (e.g., methane and other gases). This method attempts to estimate the relative weight of these components to obtain the measured spectrum. Component spectra are typically taken from a pre-defined spectral library (e.g., from a data collection that has been assembled empirically), although sometimes the scene can be used to estimate these component spectra (often referred to as "endmember determination"). In various implementations, the image obtained by the detector pixel is a radiation spectrum and provides information about the brightness of objects. To identify the composition of a gas cloud in the scene and / or estimate the concentration of various gases in the gas cloud, the absorption / emission spectra of the various gases of interest can be obtained by comparing the measured brightness with estimates of the expected brightness. Spectral unmixing can also benefit from time, parallax, and motion compensation techniques.

[0170] In various embodiments, methods for identifying the presence of a target substance in an object include obtaining a radiation spectrum (or absorption spectrum) from the object in a spectral region indicating the presence of the target substance, and calculating a correlation (e.g., a correlation coefficient) by correlating the obtained radiation spectrum (or absorption spectrum) with a reference spectrum of the target substance. The presence or absence of the target substance can be determined based on the correlation quantity (e.g., the value of the correlation coefficient). For example, if the value of the correlation quantity or correlation coefficient is greater than a threshold, the presence of the target substance in the object can be confirmed. In various embodiments, the radiation spectrum (or absorption spectrum) can be obtained by obtaining a spectral difference image between a filtered optical channel and / or another filtered optical channel / unfiltered optical channel or any combination thereof.

[0171] For example, an embodiment of a system configured to detect the presence of methane in a gas cloud includes optical components such that one or more of a plurality of optical channels are configured to collect IR radiation to provide spectral data corresponding to discrete spectral bands located in a wavelength range between approximately 7.9 μm and approximately 8.4 μm corresponding to the absorption peak of methane. The multispectral data obtained in the one or more optical channels can be correlated with a predetermined absorption spectrum of methane in the wavelength range between approximately 7.9 μm and 8.4 μm. In various embodiments, the predetermined absorption spectrum of methane can be stored in a system-accessible database or reference library. Based on the correlation quantity (e.g., the value of the correlation coefficient), the presence or absence of methane in the gas cloud can be detected.

[0172] Examples of actual implementation plans and operations

[0173] The embodiment 300 in Figure 3 is configured to employ 12 optical channels and 12 corresponding microbolometers FPA336 to capture a video sequence substantially immediately after performing calibration measurements. The video sequence corresponds to images of a standard laboratory scene, and the calibration measurements are performed using a reference source comprising two shutters, one at room temperature and one 5°C above room temperature, as described above. Using 12 FPAs allows for increased opportunities to simultaneously detect and estimate the concentrations of approximately 8 or 9 gases present at the scene. In various embodiments, the number of FPA 336 can be varied depending on the balance between operational requirements and cost considerations.

[0174] Due to its operation in the IR range of the spectrum, the use of the so-called noise equivalent temperature difference (or NETD) is preferred, and is similar to the SNR commonly used in visible spectrometers. The array of the microbolometer FPA 336 is characterized by operation at an f-number of 1.2 with a NETD ≤ 72 mK. Each measurement is performed by adding four consecutive frames, and the expected reduction in NETD due to this addition is described by the corresponding factor √4 = 2. Therefore, under ideal measurement conditions, the FPA NETD should be approximately 36 mK.

[0175] It is worth noting that using an optically filtered FPA in the various embodiments of the system described herein can provide the system with a greater number of pixels. For example, embodiments including a single large microbolometer FPA array can provide a system with a large number of pixels. The various embodiments of the system described herein can also provide high optical throughput for a relatively small number of optical channels. For example, the system described herein can provide high optical throughput for multiple optical channels between 4 and 50. By having a lower number of optical channels (e.g., between 4 and 50), the system described herein has a wider spectral bin, which allows for a larger integrated intensity of the signal acquired within each spectral bin.

[0176] The implementation described herein has the advantage over various scan-based hyperspectral systems configured for target substance detection (e.g., gas cloud detection) in that it can resolve the entire spectrum in snapshot mode (e.g., during one image frame acquisition by an FPA array). This feature allows the implementation of the imaging system described herein to utilize compensation algorithms, such as the parallax and motion compensation algorithms mentioned above. In fact, since the imaging data required to implement these algorithms is collected simultaneously with target substance-related data, the compensation algorithms are performed relative to the target substance-related data, rather than relative to data acquired at another time interval. Therefore, this rapid data acquisition improves the accuracy of the data compensation process. Furthermore, the frame rate of data acquisition is much higher. For example, the implementation of the imaging system described herein can operate at a video rate of approximately 5 Hz or higher. For example, the various implementations described herein can operate at frame rates from approximately 5 Hz to approximately 60 Hz or 200 Hz. Therefore, users can identify typical gas mixture wisps and vortices in images without obscuring these dynamic image features and other artifacts caused by scene changes (whether spatial or spectral) during long-term measurements. In contrast, scan-based imaging systems involve acquiring image data over a period exceeding the time of a single snapshot, thus blurring the target gas features in the image and inevitably reducing otherwise achievable detection sensitivity. This contrasts with the implementation of the imaging system described herein, which can detect local gas concentrations without being obscured by regions of lower gas concentrations. Furthermore, the higher frame rate allows for a much faster response to gas leaks (when detecting such leaks is the target). For example, an alarm can be triggered in fractions of a second instead of seconds.

[0177] To demonstrate the operation and gas detection capabilities of the imaging system described in this paper, based on Figure 3A The implementation scheme 300 constructed a prototype and used the prototype to detect hydrocarbon gas clouds of propylene at a distance of approximately 10 feet. Figure 7 Video frames 1 to 12, representing the gas cloud detection output 710 (represented as a light stripe) in a sequence from t=1 to t=12, are shown. Images 1 to 12 are frames selected from a video data sequence captured at a video rate of 15 frames per second. The detected propylene gas is displayed as a light stripe 710 (highlighted in red) near the center of each image. The first image was taken before the gas emerged from the nozzle of the gas container, while the last image represents the system output shortly after the nozzle was closed.

[0178] The same prototype of the system can also demonstrate the aforementioned dynamic calibration improvements by imaging a scene surrounding a system (laboratory) with a known temperature difference. The results of implementing the dynamic calibration procedure are... Figure 8A , Figure 8B As shown in the figure, the curve labeled "obj" (or "A") represents the temperature estimate of the identified region in the scene. Figure 8A , Figure 8B In each curve of the graph, the horizontal axis indicates the number of FPAs, while the vertical axis corresponds to the temperature (in degrees Celsius). Therefore, it is expected that when all detector elements receive the radiation data, this data, when interpreted as the temperature of the object, indicates that the object temperature perceived by all detector elements is the same, and any given curve will be a substantially flat line. The data corresponding to each of the multiple "obj" curves is taken from a video frame stream (50 frames in total) spaced approximately 0.5 seconds apart from each other. Figure 8A The recorded "obj" curve shown indicates inconsistency in detector element temperature regarding the object, with differences in object temperature perceived by different detector elements reaching up to approximately 2.5°C. Furthermore, all temperature estimates drift steadily frame-by-frame over time. The curve labeled "ref" (or "C") corresponds to... Figure 3A The detector estimates the temperature of the aperture 338 of the implementation scheme 300. The results of the radiation detection performed after each detector pixel has undergone the above-described dynamic calibration process are represented by a curve labeled "obj corr" (or "B"). Now, the difference in the estimated temperature of the object between detector elements is reduced to approximately 0.5°C (thus improving the original reading by at least 5 times).

[0179] Figure 8B This corresponds to different locations in the scene (temperature ratio) Figure 3A Similar measurements were taken at a location with an aperture of 338 mm and an estimated temperature approximately 9°C higher. As shown in the figure, the correction algorithm discussed above is operable and effective, and applicable to objects held at different temperatures. Therefore, the algorithm is essentially temperature-independent.

[0180] Dynamic calibration elements and references

[0181] Figure 9A and Figure 9B Different embodiments of the imaging system 900 and 905 are schematically illustrated, each including various temperature calibration elements to facilitate dynamic calibration of the FPA. The temperature calibration elements may include mirrors 975a and 975b (denoted as M). 1A M 9A(etc.) and reference sources 972a and 972b. Embodiment 900 may be configured similarly to embodiment 300 and includes one or more front objectives, a split aperture, one or more spectral filters, an array of imaging lenses 928a, and an imaging element 936. In various embodiments, the imaging element 936 (e.g., a camera module) may include a camera array. In various embodiments, the camera array may include an optical FPA unit. The optical FPA unit may include a single FPA, an FPA array. In various embodiments, the camera array may include one or more detector arrays, which one or more detector arrays in Figure 9A and Figure 9B The arrays are designated as detector array 1, detector array 5, and detector array 9. In various embodiments, the field of view (FOV) of each detector array in arrays 1, 5, and 9 can be divided into a central region and a peripheral region. Generally, without any loss of generality, the central region of the FOV of each detector array in arrays 1, 5, and 9 may include the area where the FOVs of all detector arrays 1, 5, and 9 overlap. Figure 9A In the illustrated implementation, for example, reference sources 972a and 972b are placed at a certain distance from detector arrays 1, 5, and 9, and then mirrors 975a and 975b, which can image the reference sources onto the detector arrays, are placed at the scene reference aperture (e.g., Figure 3A At position 338).

[0182] exist Figure 9AIn this configuration, mirrors 975a and 975b are configured to reflect radiation from reference sources 972a and 972b (denoted as reference A and reference B). Mirrors 975a and 975b are positioned remotely from the central field of view (FOV) of detector arrays 1, 5, and 9, ensuring that the central FOV is not obstructed or blocked by the images of reference sources 972a and 972b. In various embodiments, the FOV of detector array 5 may be larger than that of detector arrays 1 and 9. In such embodiments, mirrors 975a and 975b are positioned remotely from the central FOV of detector array 5, such that reference sources 972a and 972b are imaged by detector array 5. Mirrors 975a and 975b may include imaging optics having the optical power to image reference sources 972a and 972b onto detector arrays 1 and 9. In this example, reference sources 972a and 972b can be disposed in the same plane as the re-imaging lens 928a; however, reference sources 972a and 972b can be disposed in different planes or at different locations. For example, reference sources 972a and 972b can be disposed in a plane conjugate to the plane in which detector arrays 1, 5, and 9 are disposed, such that the focused images of reference sources 972a and 972b are formed by the detector arrays. In some embodiments, reference sources 972a and 972b can be disposed in planes spaced apart from the conjugate plane, such that the defocused images of reference sources 972a and 972b are formed by the detector arrays. In various embodiments, reference sources 972a and 972b do not need to be disposed in the same plane.

[0183] As described above, in some embodiments, reference sources 972a and 972b are imaged onto detector arrays 1 and 9 with minimal blurring, allowing reference sources 972a and 972b to be focused. Conversely, in other embodiments, the images of reference sources 972a and 972b formed on detector arrays 1 and 9 are blurred, causing reference sources 972a and 972b to be defocused, thereby providing some averaging, smoothing, and / or low-pass filtering. Reference sources 972a and 972b may include surfaces of known temperature and may or may not include heaters or coolers attached to or in thermal communication with them. For example, reference sources 972a and 972b may each include a heater and a cooler, or may include a surface with a temperature sensor and heaters and sensors in direct thermal communication with that surface to control the temperature of the reference surface. In various embodiments, reference sources 972a and 972b may include a temperature controller configured to maintain reference sources 972a and 972b at a known temperature. In some embodiments, reference sources 972a and 972b may be associated with one or more sensors that measure the temperature of reference sources 972a and 972b and transmit the measured temperature to a temperature controller. In some embodiments, the one or more sensors may transmit the measured temperature to a data processing unit. In various embodiments, reference sources 972a and 972b may include surfaces with unknown temperatures. For example, the reference sources may include the walls of a housing that houses an imaging system. In some embodiments, reference sources 972a and 972b may include surfaces that do not need to be associated with sensors or a temperature controller. However, in other embodiments, reference sources 972a and 972b may include surfaces that can be associated with sensors or a temperature controller.

[0184] exist Figure 9B In this configuration, the temperature calibration elements include temperature control elements 972a and 972b (e.g., thermal emitters, heating bands, heaters, or coolers) positioned at a distance from detector arrays 1, 5, and 9. In various embodiments, temperature control elements 972a and 972b can be positioned remotely from the central field of view (FOV) of detector arrays 1, 5, and 9, ensuring that the central FOV is not obstructed or blocked by the images from reference sources 972a and 972b. Radiation emitted from reference sources 972a and 972b is also imaged by detector array 936 along with radiation incident from the object. Depending on the position of reference sources 972a and 972b, the images obtained by the detector array of the reference sources may be blurry (or out of focus) or sharp (or in focus). Images 980a, 980b, 980c, 980d, 980e, and 980f from temperature control elements 972a and 972b can be used as a reference for dynamically calibrating one or more cameras in a camera array.

[0185] exist Figure 9A and Figure 9B In the embodiments depicted, detector arrays 1, 5, and 9 are configured to observe (or image) both reference sources 972a and 972b. Therefore, multiple frames in an image sequence (e.g., each frame or substantially each frame) contain one or more regions of an image in which the object image has known thermal and spectral properties. This allows multiple (e.g., most or each) cameras within a camera array to be calibrated to be consistent with other (e.g., most or every other) cameras imaging the same reference source or reference surface. For example, detector arrays 1 and 9 can be calibrated to be consistent with each other. As another example, detector arrays 1, 5, and 9 can be calibrated to be consistent with each other. In various embodiments, lens 928a provides a blurred (or defocused) image of reference sources 972a and 9 on detector arrays 1 and 9 because the location of the reference sources is not exactly in the conjugate plane of detector arrays 1 and 9. Although lens 928a is described as providing a blurred or defocused image, in various embodiments, the reference source or reference surface is imaged on detector arrays 1, 5, and 9 without such blurring and defocusing, and instead, a focused image is provided. Alternatively, optical elements such as Figure 9A The mirror shown is used to provide this type of focused image.

[0186] The reference sources 972b and 972a can have different temperatures. For example, reference source 972a can be located at temperature T. A Furthermore, the reference source 972b can operate below temperature T. A Temperature T B A heater can be provided below the temperature control element 972a to maintain it at temperature T. A A cooler can be provided below the temperature control element 972b to maintain it at temperature T. B In various implementation methods, Figure 9A and Figure 9B The illustrated embodiment can be configured to image a single reference source 972, rather than two reference sources 972a and 972b maintained at different temperatures. It should be understood that the single reference source does not need to be thermally controlled. For example, in various embodiments, multiple detectors in a detector array can be configured to image the same surface of at least one calibration element whose thermal and spectral characteristics are unknown. In such embodiments, one of the multiple detectors can be configured as the reference detector, and the surface temperature of the at least one calibration element imaged by the multiple detectors can be estimated using the radiation spectrum obtained by the reference detector. The remaining multiple detectors can be calibrated such that their temperature and / or spectral measurements are consistent with those of the reference detector. For example, detector arrays 1 and 9 can be calibrated to be consistent with each other. As another example, detector arrays 1, 5, and 9 can be calibrated to be consistent with each other.

[0187] Reference sources 972a and 972b can be coated with a material to essentially behave as blackbodies (for which the emission spectrum is known for any given temperature). If a temperature sensor is used at the location of each reference source, the temperature can be tracked at those locations. Therefore, a region in the image of each camera (e.g., on detector arrays 1 and 9) can be defined where the object has such a known temperature (and therefore the spectrum). Thus, a calibration procedure can be used such that for objects at the temperatures represented by these two sources, most cameras (if not every camera) operating in this way are operationally consistent with most or every other camera. Calibrating an infrared camera using sources at two different temperatures is called “two-point” calibration and assumes that the measured signal at a given pixel is linearly related to the incident irradiance. Because this calibration can be performed over multiple, more, or even every frame of a sequence, it is called “dynamic calibration.”

[0188] An example of a dynamic calibration procedure is shown below. If there are temperature sensors on a reference source or reference surface, the temperature measurements obtained from these sensors can be used to determine their expected emission spectra. These temperature measurements are labeled T for the "reference temperatures" of sources / surfaces A, B, and C. A [R]、T B [R] and T C [R]. These temperature measurements can be used as a scalar correction factor to be applied to the entire image of a given camera, thus forcing it to conform to a reference temperature. The temperature estimate for correcting a given pixel from T to T' can be obtained using a method similar to the reference below. Figure 10A , Figure 10B , Figure 10C The formulas discussed. If a direct temperature sensor is not used, one of these cameras can be used instead. This camera can be referred to as the "reference camera". In this case, the same formula as provided in the following paragraphs can be used, but T... A [R] and T B [R] represents the temperatures of the reference source / reference surfaces A and B estimated by the reference camera. By applying a dynamic calibration correction formula, all other cameras are forced to match the temperature estimates of the reference camera.

[0189] exist Figure 9B In the configuration shown, reference sources 972a and 972b are positioned such that the image of the sources on the detector array is blurred. Figure 9A The configuration shown is similar to Figure 4 The system 400 shown has a reference source placed in an intermediate image plane (e.g., a conjugate image plane). In this configuration, similar to... Figure 4The reference aperture 438a in the reference aperture array will have an accompanying array of reference sources or reference surfaces, such that the reference sources or reference surfaces (e.g., each reference source or reference surface) are imaged onto camera or detector arrays such as FPA 1, 5, 9. Using this method, the images of the reference sources or reference surfaces are in a conjugate image plane and therefore will not be significantly blurred, allowing their images to block a small portion of the field of view of each camera.

[0190] "Static" calibration (where the scene is referenced by a source such as...) Figure 9A and Figure 9B The moving shutter 960 in the process largely blocks the procedure, making it impossible to perform imaging of unknown scenes in parallel with calibration. This allows multiple cameras (e.g., most cameras or each camera) to accurately estimate the temperature of multiple components (e.g., most or each component in the scene) immediately after calibration is complete. However, it cannot prevent camera estimates from drifting relative to each other during the process of imaging an unknown scene. Dynamic calibration can be used to reduce or prevent this drift, thereby forcing all cameras imaging the scene to agree on the temperature estimates of a reference source / reference surface and adjusting this correction during each frame.

[0191] Figure 10A The schematic illustration shows a related implementation scheme 1000 of the imaging system, in which one or more mirrors M 0A M 11A and M 0B M 11B The mirrors are placed within the field of view of one or more cameras 0, ..., 11, thereby partially obstructing the field of view. Cameras 0, ..., 11 are arranged to form an outer ring of cameras 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4 surrounding the central camera 5 and 6. In various embodiments, the field of view (FOV) of the central camera 5 and 6 may be less than or equal to the FOV of the outer ring of cameras 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4. In such embodiments, one or more reflectors M... 0A M 11A and M 0B M 11B It can be placed outside the central FOV of cameras 5 and 6, and within the peripheral FOV of the outer ring of cameras 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4, which does not overlap with the central FOV of cameras 5 and 6, so that reference sources A and B are not imaged by cameras 5 and 6. In various embodiments, the FOV of the central cameras 5 and 6 can be larger than the FOV of the outer ring of cameras 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4. In such embodiments, one or more reflectors M 0A M 11A and M 0BM 11B It can be placed in the outer FOV of cameras 5 and 6, which overlaps with the central FOV of the outer ring of cameras 0, 1, 2, 3, 7, 11, 10, 9, 8 and 4, so that reference sources A and B are imaged by cameras 5 and 6.

[0192] This design is... Figure 3A and Figure 4 Enhancements to systems 300 and 400 are shown in Figure A. Figure 10A In the system 1000 shown, an array of two or more imaging elements (e.g., curved mirrors) is mounted at a distance from the FPA, for example, in Figure 3A The reference aperture 160 is shown in the plane. These elements (mirrors or imaging elements) are used to image one or more temperature-controlled reference sources A and B onto the detector elements of two or more cameras in the camera. The main difference between embodiment 1000 and embodiment 300 or 400 is that now multiple or most or all of the outer ring cameras in the array can image both reference sources A and B, instead of image one of the two reference sources A and B. Therefore, most or all of the outer ring cameras image the same reference source or the same set of reference sources (e.g., both reference sources A and B), instead of as Figure 3A and Figure 4 As shown in Figure A, different reference sources are used for different cameras, or different parts of the reference sources are imaged. Therefore, this method improves the robustness of calibration because it eliminates potential faults and errors caused by using additional thermal sensors to estimate each reference source.

[0193] The imaging element in system 1000 (in Figure 10A and Figure 10B (As shown in the image) will calibrate one or more temperature-controlled reference sources or reference surfaces (in the image) of the calibration element. Figure 10A and Figure 10B The images (shown as A and B) are projected into the obstructed areas of the camera's field of view. Figure 10B An example is shown where the reflector M 0A The reference source / reference surface A is imaged onto camera 0, and the mirror M... 0BA reference source / reference surface B is imaged onto camera 0, and the same applies to cameras 1, 2, and 3. Thus, each mirror in the array is used to image the reference source / reference surface onto the camera's detector array, such that many, most, or each frame within an image sequence contains one or more regions of the image in which the object image has known thermal and spectral properties. This method allows most (if not every) cameras in the camera array to be calibrated to be consistent with most or every other camera imaging the same one or more reference sources. For example, cameras 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4 can be calibrated to be consistent with each other. As another example, cameras 0, 1, 2, and 3 can be calibrated to be consistent with each other. As yet another example, cameras 0, 1, 2, 3, 7, 11, 10, 9, 8, 4, 5, and 6 can be calibrated to be consistent with each other. Therefore, in various embodiments, two, three, four, five, six, seven, eight, nine, ten, eleven, or twelve cameras can be calibrated to be consistent with each other. However, in some embodiments, not all cameras are calibrated to be consistent with each other. For example, one, two, or more cameras may not be calibrated to be consistent with each other, while other cameras may be calibrated to be consistent with each other. In various implementations, these mirrors can be configured to image reference sources / reference surfaces A and B onto different corresponding pixels at a given FPA. Without loss of generality, Figure 10A and Figure 10B express Figure 9A The top view of the embodiment shown.

[0194] Figure 10C An embodiment 1050 of an imaging system is schematically illustrated, wherein one or more reference sources R 0A ..., R 11A and R 0B ..., R 11B They are positioned around the array of detectors 0, ..., 11. In various implementations, one or more reference sources R 0A ..., R 11A and R 0B ..., R 11B It can be a single reference source imaged by detectors 0, ..., 11. In various embodiments, the central detector arrays 5 and 6 can have an FOV equal to or less than the FOV of the outer ring of detectors 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4. In such embodiments, the reference source R... 0A ..., R 11A The FOV setting can be moved away from the central FOV of detector arrays 5 and 6, allowing the reference source R to... 0A ..., R 11AThe radiation is imaged only by the outer rings of detectors 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4. In various embodiments, the central detector arrays 5 and 6 can have a larger FOV than the outer rings of detectors 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4. In such embodiments, the reference source R... 0A ..., R 11A It can be set in the outer FOV of detector arrays 5 and 6, so that the light from the reference source R 0A ..., R 11A The radiation is imaged only by the outer rings of detectors 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4. Therefore, the radiation from the reference source R... 0A ..., R 11A The radiation was imaged by the outer rings of detectors 0, 1, 2, 3, 7, 11, 10, 9, 8, and 4, and by the central cameras 5 and 6. Under normal circumstances without any loss of uniformity, Figure 10C express Figure 9B The top view of the embodiment shown.

[0195] In various implementations, the heater may be positioned below, near, or in thermal communication with the reference source / reference surface A to give it a high temperature T. A Furthermore, the cooler can be positioned below, near, or in thermal connection with the reference source B to achieve a lower temperature T. B In various implementation methods, Figure 10A , Figure 10B and Figure 10C The illustrated implementation can be configured to image a single reference source A, rather than two reference sources A and B maintained at different temperatures. As described above, Figure 10A , Figure 10B and Figure 10CThe illustrated implementation can be configured to image the same surface of the calibration element. In such implementations, it is not necessary to know the temperature of the calibration element's surface. Many, most, or each reference source / reference surface can be coated with a material to make it essentially behave as a blackbody, for which the emission spectrum is known at any given temperature. If many, most, or each camera in a camera array images both references A and B such that a known region exists in the images from these cameras where the object has a known temperature (and therefore a known spectrum), a calibration process can be performed. The procedure can be specified that, for an object at the temperature represented by the two sources, many, most, or each camera operating in this manner is consistent with various, most, or each of the other cameras. For example, two, three, four, five, six, seven, eight, nine, ten, eleven, or twelve cameras can be calibrated to be consistent with each other. However, in some implementations, not all cameras are calibrated to be consistent with each other. For example, one, two, or more cameras may not be calibrated to be consistent with each other, while other cameras may be calibrated to be consistent with each other. As mentioned above, calibrating an infrared camera using sources at two different temperatures is called “two-point” calibration, and it is assumed that the measured signal at a given pixel is linearly related to the incident irradiance.

[0196] Dynamic calibration is used to obtain the corrected temperature T' from the initial temperature T estimated at each pixel in the camera using the following formula:

[0197] T'[x,y,c]=(T[x,y,c]-T A [R])G[c]+T A [R]

[0198] Where T A [R] is the dynamic offset correction coefficient, and This is the dynamic gain correction factor. The term 'c' discussed above is the camera index that identifies the camera whose data is being corrected.

[0199] III. Examples of Mobile DAISI Systems

[0200] According to some embodiments, the DAISI system disclosed herein can be configured for long-term installation at a suitable location. For example, the DAISI system disclosed in Part II above can be attached to a clamp that is mounted to the ground at a specific location to continuously or periodically monitor the presence of gases or chemicals at that location. In some embodiments, for example, the DAISI system can be attached to a pole, post, or any suitable clamp at the location to be monitored. In such an arrangement, the DAISI system can continuously or periodically capture multispectral, multiplexed image data of the scene, and an onboard or remote computing unit can process the captured image data to identify or characterize the gases or chemicals at the location. A communication module can transmit data related to the identified gases or chemicals to any suitable external system, such as a central computing server. For such long-term installations of the DAISI system, the installation site may include power (e.g., power lines connected to a junction box at the site) and network communication equipment (e.g., network cabling, routers, etc.) to provide network communication between the DAISI system and external systems.

[0201] It may be advantageous to provide mobile DAISI systems configured for wear or carry by users. For example, it may not be suitable or desirable to install DAISI systems in certain locations for extended periods. As an example, some well sites may lack sufficient infrastructure (such as power or network communication equipment) to support a DAISI system. Furthermore, moving a DAISI system from one site to another to monitor different locations can be challenging. For instance, installing and removing a DAISI system for transport when connected to infrastructure at the site to be monitored can require significant effort and time from the user. Therefore, it may be desirable to provide DAISI systems that can be used independently of the facilities or infrastructure at the site to be monitored. Additionally, it may be advantageous to implement DAISI systems with a form factor and weight that allows them to be carried or worn by users. For example, a mobile DAISI system allows users to easily transport the system from one site to another while simultaneously monitoring the presence of gases or chemicals in real time.

[0202] It should be understood that each system disclosed herein can be used to monitor potential gas leaks in any suitable installation site, including but not limited to drilling rigs, refineries, pipelines, transportation systems, ships or other vessels (such as offshore oil rigs, trains, tanker trucks, petrochemical plants, chemical plants, etc.). Furthermore, this document, such as in the context of the above, refers to... Figures 1 to 10C Each disclosed and illustrated embodiment and aspect may be compared with this document. Figures 11A to 14C Each disclosed and shown implementation is used in combination.

[0203] Figure 11AThis is a schematic diagram illustrating a mobile infrared imaging system 1000 (e.g., a mobile or portable DAISI system) configured to be carried or worn by a human user 1275. The user 1275 may wear a hat or helmet 1200 when traveling to a site to be monitored (such as an oil well site, a refinery, etc.). Figure 11A The illustrated system 1000 is attached to a helmet 1200 via a support 1204 that securely mounts the system 1000 to the helmet 1200. For example, the support 1204 may include fasteners, straps, or any other suitable structure. Advantageously, mounting the system 1000 to the helmet 1200 allows the user 1275 to capture images within the system's field of view (FOV) by rotating their head to face a specific location to be monitored. For example, the user 1275 may walk across the area and capture video images of each part of the area (e.g., various structures that might be prone to gas or chemical leaks, such as valves, fittings, etc.). Therefore, in Figure 11A In the illustrated implementation, user 1275 can image each part of the field by facing the area to be imaged and ensuring system 1000 is activated. Furthermore, by mounting system 1000 to the user's helmet 1200, user 1275 can use their hands to perform other tasks while system 1000 images the field. Although Figure 11A System 1000 is shown as mounted on a user's helmet 1200, but it should be understood that system 1000 may conversely be worn on other parts of the user's clothing or carried by the user (e.g., placed in a bag, box, or other suitable container). Furthermore, in some embodiments, a wind sensor may be provided to the user, for example, located on or near the user's clothing and / or on or near system 1000. The wind sensor can be used to estimate wind conditions at the installation site, which can be used to improve the detection of gas leaks. In other embodiments, system 1000 may be coupled to or formed with a housing that defines a "gun-like" structure that can be aimed or pointed at by the user in a specific direction.

[0204] As explained herein, the gas cloud 1202 emitted from the structure at the site can be imaged by pointing the system 1000 at the gas cloud 1202 and capturing an image of the gas cloud 1202 while it is within the field of view (FOV) of the system 1000. Unlike other systems, the system 1000 can capture multispectral image data of a single scene across a range of IR wavelengths using a single snapshot, as explained in further detail herein. A single snapshot can be captured in short frames, such as less than about 3 seconds, less than about 2 seconds, or less than about 1.5 seconds (e.g., in some embodiments, within about 1 second). A single snapshot can be captured in longer frames, such as greater than about 5 milliseconds, greater than about 0.2 seconds, or greater than about 0.5 seconds. The captured image data can be processed on-board by a processing unit on the system 1000, as explained in further detail herein. For example, the processing unit can process image data from different optical channels and can compare the captured spectral information with a database of known chemicals to identify and / or characterize the gases contained in the gas cloud 1202.

[0205] The onboard communication module of System 1000 can transmit information related to the identified gas or chemical to any suitable external device. For example, the communication module can wirelessly transmit this information (e.g., via Bluetooth, WiFi, etc.) to a suitable mobile computing device, such as electronic glasses device 1201, tablet computing device 1212, mobile smartphone, laptop or notebook computer 1203, or any other suitable mobile computing device. In some embodiments, if a gas cloud is detected, System 1000 can warn a user by sending a signal to a mobile device (e.g., tablet computing device 1212 or mobile smartphone). The mobile device may emit an audible ring and / or vibrate to notify the user of a potential gas leak. Figure 11A In some embodiments, the electronic glasses device 1201 may include a user interface including a display that a user 1275 can view in real time while visiting a location. In some embodiments, the electronic glasses device 1201 includes glasses that include a display. The electronic glasses device 1201 may be further configured to present an image from the display to the wearer. The electronic glasses device 1201 may, for example, include projection optics that project an image into the eyes. The electronic glasses device 1201 may include head-up display electronics that present an image on one or more lens portions of the glasses so that the wearer can view the image and also look at and gaze at distant objects through the glasses. Other configurations are possible. In some arrangements, the glasses device 1201 may include Google Glass devices sold by Google, Inc., Mountain View, California.

[0206] The processing unit can configure the processed image data to display the identified gas type to the user 1275 on the display of the glasses device 1201. For example, in some embodiments, color-coded data can represent different types of gases or different concentrations of a specific gas and can be superimposed on a visible light image of the scene. For example, the user can see color-coded data and images of a gas cloud on the electronic glasses device 1201. In various embodiments, textual data and statistical values ​​regarding the composition of the gas cloud 1202 can also be displayed to the user 1275. Thus, the user 1275 can walk through the site and view different types of gases in the gas cloud 1202 substantially in real time. Advantageously, this real-time display of the composition of the gas cloud 1202 enables the user 1275 to quickly report emergencies, such as leaks of toxic gases or chemicals. In some embodiments, the detection of a toxic substance leak can trigger an alarm, thereby enabling emergency personnel to assist in evacuating the site and / or repairing the leak.

[0207] In some implementations, processed image data can be transferred from system 1000 to tablet computing device 1212, laptop computer 1203, and / or smartphone. User 1275 can interact with tablet computing device 1212 or laptop computer 1203 for additional analysis of the imaged and processed air cloud 1202. Furthermore, information about the air cloud (including processed data and / or raw image data) can be transferred to a central server for centralized collection, processing, and analysis. In various arrangements, a Global Positioning System (GPS) module can also be mounted airborne on system 1000 and / or on a mobile computing device (such as a tablet computing device, smartphone, etc.). The GPS module can identify the coordinates of user 1275 when a specific image is captured. The location data of the captured image data can be stored on a central server for further analysis.

[0208] therefore, Figure 11A The illustrated system 1000 enables user 1275 to image multiple locations of a specific site to be monitored, such as an oil well site. Advantageously, the optical, processing, and communication components of system 1000 can be integrated into a relatively small housing that can be carried or worn by user 1275. For example, in various embodiments, system 1000 does not include complex mechanical components for movement, such as balance rings, actuators, motors, etc. The absence of such components reduces the size of system 1000 compared to other systems.

[0209] Unlike other systems with bulky components or assembled with a large form factor, the size and shape of the mobile system 1000 can be configured to allow the user 1275 to easily move and manipulate the mobile system as they move around the site. In practice, integrating various system components with a small form factor can be very challenging. Advantageously, the system 1000 can be worn or carried by a human user. For example, the components of the system 1000 can be housed together in a data acquisition and processing module 1020, which may include a housing to support the system components. The components of the system 1000 (including optical or imaging components, focal plane arrays, airborne processing electronics, and communication components) can be packaged or assembled in the data acquisition and processing module 1020 and can occupy a volume of less than about 300 cubic inches, less than about 200 cubic inches, or less than about 100 cubic inches. In various implementations, the components of system 1000 (including optical or imaging components, focal plane arrays, airborne processing electronics, and communication components) may be packaged or assembled in data acquisition and processing module 1020 and may occupy a volume greater than about 2 cubic inches or greater than about 16 cubic inches.

[0210] The size and shape of the data acquisition and processing module 1020 (wherein or on which system components are mounted) may be configured to fit within a frame boundary having dimensions X×Y×Z. For example, the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be included in a package whose size and shape are configured to fit within a frame boundary having dimensions X×Y×Z. The package may also include a power supply, such as a battery and / or a solar module. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be configured to fit within a frame boundary smaller than 8 inches × 6 inches × 6 inches. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be configured to fit within a frame boundary smaller than 7 inches × 5 inches × 5 inches, for example, a frame boundary smaller than 7 inches × 3 inches × 3 inches. In some embodiments, the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be sized and shaped to fit within a frame boundary smaller than 6 inches × 4 inches × 4 inches. In some embodiments, the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be sized and shaped to fit within a frame boundary smaller than 2 inches × 2 inches × 6 inches. In some embodiments, the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be sized and shaped to fit within a frame boundary having dimensions greater than 4 inches × 2 inches × 2 inches. In some embodiments, the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be sized and shaped to fit within a frame boundary having dimensions greater than 3 inches × 3 inches × 7 inches. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) can be configured to fit within a frame boundary having dimensions greater than 2 inches × 1 inch × 1 inch. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have dimensions less than 2 inches × 2 inches × 6 inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have dimensions greater than 1 inch × 1 inch × 3 inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have dimensions greater than 2 inches × 2 inches × 4 inches. The data acquisition and processing module has dimensions less than 6 inches × 3 inches × 3 inches.The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a size of less than 4 inches × 3 inches × 3 inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a size of less than 3 inches × 2 inches × 2 inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a size greater than 2 inches × 1 inch × 1 inch. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a size greater than 1 inch × 0.5 inches × 0.5 inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of less than 30 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of less than 20 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of less than 15 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of less than 10 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of more than 1 cubic inch. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of more than 4 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of more than 5 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of more than 10 cubic inches. The package may also include a power supply (including a battery and / or a solar module), a communication module, or both, and conform to the dimensions mentioned above. It should be understood that the dimensions disclosed herein may not correspond to specific dimensions. Figure 11A Regarding the directions indicated by X, Y, and Z.

[0211] Furthermore, the system 1000 can have a sufficiently small mass and weight to allow the user 1275 to easily carry or wear the data acquisition and processing module 1020 at the site. Therefore, Figure 11A The dimensions and shape of the illustrated embodiment can be set and configured to have a mass that allows human users to easily and effectively operate the system 1000.

[0212] Figure 11B This is a schematic diagram illustrating an installation site (e.g., an oil well site, etc.) that can be monitored by multiple infrared imaging systems 1000 (e.g., a DAISI system). For example, as Figure 11B As shown, imaging system 1000A can be mounted to pole 1309 or other fixed structure at the installation site. Imaging system 1000B can be worn or carried by multiple users 1275, imaging system 1000C can be mounted on truck 1500, and / or imaging system 1000D can be mounted on aerial platform 1501 (such as an unmanned aerial vehicle (UAV) or a manned aircraft). In some arrangements, the UAV may include an aircraft, a helicopter (such as a quadcopter), etc. The embodiments disclosed herein can utilize image data captured at the installation site by any combination of systems 1000A-1000D to image the entire installation site in an efficient manner. In practice, each installation site may include any suitable number and type of systems 1000A-1000D. For example, each installation site may include more than two systems 1000A-1000D, more than five systems 1000A-1000D, more than ten systems 1000A-1000D, or more than twenty systems 1000A-1000D. Each installation site may include fewer than approximately 100 systems 1000A-1000D.

[0213] For example, the central server can track the real-time location of each imaging system 1000A-1000D based on the GPS coordinates of a specific system or predetermined knowledge about the system's fixed location. The distributed nature of the imaging systems 1000A-1000D can provide the central server with rich information about the type and location of gas leaks or other issues across multiple installation sites. Although Figure 11B A fixed system 1000A mounted to a gripper, a portable system 1000B worn or carried by a human, a truck-based system 1000C, and an aerial system 1000D are illustrated, but it should be understood that other types of systems may also be suitable. For example, in some embodiments, a robotic vehicle or walking robot may be used as a platform for the system 1000 disclosed herein. In various embodiments, a floating platform (such as a vessel) may be used as a platform for the system 1000 disclosed herein. It should also be understood that the system disclosed herein may utilize any combination of platforms (e.g., fixed grippers (such as poles), one or more human users, one or more trucks or other vehicles, one or more aerial platforms, one or more floating platforms, one or more robotic platforms, etc.) to support the system 1000.

[0214] Figure 11B The system 1000 shown may include and Figure 11A A similar mobile DAISI system is shown. In other embodiments, system 1000 may include a larger DAISI system configured for relatively long-term use. For example, Figure 11BThe fixed imaging system 1000A shown can be mounted on pole 1309 or other suitable structure to monitor tank 1301. Solar panel 1300 can be located at or near system 1000 to help provide power to system 1000. Antenna 1303 can be electrically coupled to the system and can provide wireless communication between system 1000 and any other external entity (such as a central server) for storing and / or processing data captured by system 1000.

[0215] If needed, a DAISI system (such as system 1000) can be coupled to a unit that adjusts the translation, tilt, rotation, height, or other position of system 1000. As an example, system 1000 can be mounted to a translation and tilt unit. The translation and tilt unit may be able to rotate the front of system 1000 left and right (e.g., to rotate the yaw system 1000 left and right) and to rotate the front of system 1000 up and down (e.g., to rotate the pitch system 1000 up and down), thereby enabling system 1000 to focus on a specific portion of the surrounding environment and scan different areas of the surrounding environment when needed (i.e., through a desired scan path). The translation and tilt unit (or any other unit that adjusts the position of system 1000) may include a motor, actuator, or other suitable mechanism to drive the movement of system 1000. The operation of the translation and tilt unit (or any other unit that adjusts the position of the system 1000) can be controlled by the system 1000, by the translation and tilt unit, by a remote system, by a control system capable of controlling one or more systems 1000 and / or corresponding translation and tilt units, or by any suitable and desired control system.

[0216] The fixed infrared imaging system 1000A can be programmed for continuous or periodic site monitoring. If gas cloud 1302 escapes from storage tank 1301 (e.g., through leakage from a ruptured valve), system 1000A can capture multispectral snapshot images or a series of images (e.g., a video stream) of gas cloud 1302. Figure 11A Similar to the implementation scheme, the imaging system 1000A may include onboard imaging, processing and communication components to identify and characterize the types of gas in the cloud 1302 and transmit the processed data, for example, via the antenna 1303, to a central server.

[0217] An imaging system 1000B, worn or carried by multiple users 1275, can advantageously capture and process multispectral image data of portions of the installation site visited by each user 1275. It should be understood that different users 1275 may work in or pass through different portions of the installation site (and also visit multiple installation sites) over a period of time. When activated, the imaging system 1000B worn or carried by the user 1275 can continuously or periodically capture multispectral image data of different locations at one or more installation sites visited by the user 1275. As explained herein, the system 1000B can transmit the image data and the location where the image was captured to a central server. If the system 1000B or the central server detects a problem (such as a gas leak), the central server can associate the leak with a specific location and time.

[0218] Furthermore, because the central server can receive image and location data from multiple users at different locations and viewing angles, it can create an organization-level map of gas leaks. This map includes, for example, the location of the gas leak at any of multiple installation sites, the type and concentration of each leaked gas and its area or extent, the specific user 1275 who captured the image data, and the time the image was taken. Therefore, each user 1275 carrying or wearing the portable imaging system 1000B can provide information to the central server, which, when aggregated by the central server, provides rich detail about the status of any gas leak at any installation site throughout the organization.

[0219] The 1000C truck-mounted imaging system can be installed on trucks or other types of vehicles (such as cars, vans, all-terrain vehicles, etc.). Figure 11BAs shown, the imaging system 1000C can be connected to one end of an extendable pole or extension member mounted on the truck 1500. The control system can raise and lower the system 1000C to enable imaging of a wide area of ​​the installation site. In some embodiments, actuators may be provided to change the angular orientation of the system 1000C, such as its pitch and yaw. Vibration isolation or damping mechanisms may also be provided to reduce vibrations that could interfere with the imaging process. The system 1000C may be battery-powered and / or truck-powered; in some embodiments, a generator may be used to power the system 1000C. The user can drive the truck 1500 across the entire installation site to image different portions of the site, thereby detecting leaks. Furthermore, the user can drive the truck 1500 to other installation sites to detect gas leaks. As explained herein, the location of the truck 1500 can be transmitted to a central server, and the location of the truck 1500 can be associated with each captured image. Truck 1500 may include GPS electronics to help track the location of truck 1500 and / or system 1000C over time as a user drives from one location to another. Similarly, aerial platform 1501 (such as an unmanned aerial vehicle or UAV) may support imaging system 1000D. Aerial platform 1501 may be guided (remotely or remotely) to multiple installation sites to capture multispectral image data for detecting atmospheric clouds.

[0220] Therefore, the System 1000A-1000D can provide a wealth of data relating to the presence of leaks at multiple facilities throughout an organization. Simultaneous or parallel monitoring of multiple cameras across an organization, site, region, or country can be achieved, at least in part, through wireless (or wired) communication between the System 1000A-1000D and one or more central servers. Advantageously, collecting image data from multiple sources and platforms enables organizations to create real-time maps of potential gas leaks, the type and amount of leaked gas, the location of the leak, and the time when image data of the leak was captured. In some arrangements, the aggregation of site data can improve site safety. For example, if a gas leak is detected at a particular facility, the embodiments disclosed herein can alert appropriate personnel who can initiate safety and / or evacuation procedures. Furthermore, the aggregation of data across an organization (such as an oilfield services company) can provide site-level, regional-level, and / or company-level performance metrics. For example, a given facility can monitor its total emissions over time, and the resulting data can be used to help determine the overall performance of the facility. A given region (such as a metropolitan area, state, etc.) can monitor emission trends over time, providing values ​​as a basis for decision-making. Similarly, companies can examine emission performance at all their facilities and make decisions about whether new investments should be made in some facilities to improve performance and / or whether various improvements should be made company-wide. Therefore, the mobile system 1000 disclosed herein provides a universal monitoring system for decision-making. Furthermore, the system 1000 disclosed herein can be used in feedback control processes to improve various manufacturing processes based on gases detected by one or more systems 1000. Therefore, control modules can be provided to adjust manufacturing processes and / or parameters according to gases measured by the system 1000.

[0221] The mobile infrared imaging system 1000 disclosed herein offers various advantages over other systems. As explained above, the aggregation of data on a site and its potential gas leaks provides an organizational or system-level map of the potential problem. Furthermore, automated detection of gas leaks (and identification of gases in gas clouds) simplifies the operation of the system 1000 and reduces the risk of user errors when attempting to manually detect or identify gas clouds. Moreover, the small size of the system 1000 disclosed herein makes it easier for users to carry or wear compared to other systems. Additionally, the system 1000 disclosed herein can overlay identified gas clouds onto a visible light image of the scene and can color-code the gas clouds according to, for example, gas type and concentration.

[0222] Figure 12This is a schematic system block diagram illustrating a mobile infrared imaging system 1000 (e.g., a mobile DAISI system) according to one embodiment. The imaging system 1000 may include a data acquisition and processing module 1020 configured to be worn or carried by a person. The data acquisition and processing module 1020 may include, contain, or house an optical system 1015, a processing unit 1021, a power supply 1026, a communication module 1025, and a GPS module 1025. In other embodiments, the data acquisition and processing module 1020 may be configured to be mounted to a structure, such as a post, at the site to be monitored. The power unit 1026 may be airborne on the system 1000. The power unit 1026 may be configured to power various system components such as the optical system 1015, the processing unit 1021, the communication module 1024, and / or the GPS module 1025. In some embodiments, the power unit 1026 may include one or more batteries (which may be rechargeable) to power the system components. In some embodiments, power unit 1026 may include a solar power generation system comprising one or more solar panels that supply power to the system by sunlight. In some embodiments, power unit 1026 may include various power electronics circuitry for converting AC power supplied by a standard transmission line into DC power to power system components. Other types of power supplies may be suitable for power unit 1026.

[0223] System 1000 may include an optical system 1015 configured to capture multispectral image data in a single snapshot, as explained herein. Optical system 1015 may correspond to any suitable type of DAISI system, such as, but not limited to, those described above. Figures 1 to 10C The optical systems and devices shown and / or the following Figures 13A to 13B The optical system 1015 shown is illustrated. For example, the optical system 1015 may include an optical focal plane array (FPA) unit and components defining at least two optical channels that are spatially and spectrally different from each other. These two optical channels may be positioned to redirect IR radiation incident on the optical system toward the optical FPA. Multiple channels can be used to multiplex different spectral images of the same scene and to image different spectral images onto the FPA unit.

[0224] Processing unit 1021 may also be mounted on the data acquisition and processing module 1020. Processing unit 1021 may include processor 1023 and memory 1022. Processor 1023 may operatively cooperate with memory 1022, which may contain computer-readable code that, when loaded onto processor 1023, enables processor 1023 to acquire multispectral optical data representing a target substance, representing a gas or chemical, from IR radiation received from the optical FPA unit of optical system 1015. Memory 1022 may be any suitable type of memory (such as a non-transitory computer-readable medium) that stores data captured by optical system 1015 and / or processed by processing unit 1021. Memory 1022 may also store software that executes on processor 1023. Processor 1023 may be configured to execute software instructions that process the multispectral image data captured by optical system 1015. For example, processor 1023 may analyze different images detected by FPA and may compare the captured data with known characteristics of various types of gases or chemicals. Based on the analysis of the captured image data, the processor can be programmed to determine the type and concentration of gas in the gas cloud. Furthermore, as explained herein, the processor 1023 can analyze calibration data provided by the optical system 1015 to improve the accuracy of the measurement.

[0225] Advantageously, the processor 1023 may include one or more field-programmable gate arrays (FPGAs) configured to perform methods used in the analysis of images captured by the optical system 1015. For example, the FPGA may include logic gates and read-access memory (RAM) blocks designed to rapidly implement calculations for detecting gas types in gas clouds. The small size / weight and high performance of the FPGA enable onboard computing and analysis within the user-worn or carried data acquisition and detection unit 1020. The use of an onboard FPGA (or similar electronics) in system 1000 reduces the costs associated with image analysis calculations using an off-site central server or larger computing devices. Furthermore, implementing computation using one or more onboard FPGA devices in a wearable system prevents or reduces communication bottlenecks associated with wirelessly transmitting large amounts of raw data from system 1000 to a remote server or computer (which may be used in some embodiments).

[0226] The communication module 1024 may be configured to communicate with at least one device physically separate from the data acquisition and processing module 1020. For example, the communication module 1024 may include a wireless communication module configured to wirelessly communicate with the at least one separate device. The wireless communication module may be configured to provide wireless communication via a wireless network (e.g., a WiFi internet network, a Bluetooth network, etc.) and / or via a telecommunications network (e.g., a 3G network, a 4G network, etc.).

[0227] In some embodiments, for example, a wireless communication module can provide data communication between the data acquisition and processing module 1020 and a mobile device (such as electronic glasses, a tablet computer, a mobile smartphone, a laptop or notebook computer, or any other suitable mobile computing device). As explained herein, the mobile device may include a display on which processed image data can be shown to a user. For example, the type (and / or concentration) of gas in a cloud may be shown on the display, for example, through color coding or other suitable graphic schemes. In some arrangements, the processed data may be overlaid on a visible light image of the scene. In some embodiments, the wireless communication module can provide data communication between system 1000 and external devices (such as a central server) located remotely from system 1000. For example, processed image data and / or raw image data may be transmitted over a telecommunications network to a central server for storage and / or further analysis. In some embodiments, processed image data or raw image data may be uploaded to a mobile device (e.g., a notebook computer, smartphone, tablet computer, etc.), which may then transmit the image data to a central server.

[0228] GPS module 1025 can be configured to determine the location of data acquisition and processing module 1020 at a specific time. In some arrangements, processing unit 1021 can store location data and associate the location data with specific images captured by optical system 1015. In some arrangements, the location data associated with the captured images can be transmitted to a central server by communication module 1024 (or by an external device).

[0229] Optical system 1015, processing unit 1021, power supply 1026, communication module 1024, and / or GPS module 1025 may be included or housed within a data acquisition and processing module 1020 that can be carried or worn by a user. Components of system 1000 (including optical components, processing components, and communication components) may be packaged or assembled within data acquisition and processing module 1020 and may occupy a volume of less than about 300 cubic inches, less than about 200 cubic inches, or less than about 100 cubic inches. In various embodiments, components of system 1000 (including optical components, processing components, and communication components) may be packaged or assembled within data acquisition and processing module 1020 and may occupy a volume of greater than about 2 cubic inches or greater than about 16 cubic inches. A power supply (including a battery and / or solar module) may also be included within components packaged or assembled within data acquisition and processing module 1020 and conform to the aforementioned dimensions.

[0230] The size and shape of the data acquisition and processing module 1020 (which, or on which, system components including imaging optics, a focal plane array, and onboard processing electronics are mounted) can be configured to fit within a frame boundary having dimensions X×Y×Z. For example, in some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) can be configured to fit within a frame boundary smaller than 8 inches × 6 inches × 6 inches. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) can be configured to fit within a frame boundary smaller than 7 inches × 5 inches × 5 inches. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) can be configured to fit within a frame boundary smaller than 6 inches × 4 inches × 4 inches. In some embodiments, the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be sized and shaped to fit within a frame boundary having dimensions greater than 4 inches × 2 inches × 2 inches. In some embodiments, the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be sized and shaped to fit within a frame boundary having dimensions greater than 2 inches × 1 inch × 1 inch. A power supply (including a battery and / or a solar module, a communication module, or both) may be included in the data acquisition and processing module 1020 and conforms to the dimensions mentioned above. It should be understood that the dimensions disclosed herein may not correspond to… Figure 11A Regarding the directions indicated by X, Y, and Z. Furthermore, the system 1000 may have a sufficiently small mass and weight to allow the user 1275 to easily carry or wear the data acquisition and processing module 1020 at the site.

[0231] Figure 13A This is a schematic system diagram of an optical system 1015 according to various embodiments, configured for use in the mobile infrared imaging system 1000 disclosed herein. As explained herein, Figure 13A The optical system 1015 shown can be incorporated into the data acquisition and processing module 1020, which is worn or carried by the user. The optical system 1015 can be configured to capture multispectral image data of an object 1007 (such as a cloud of gas, a chemical spill, etc.). Figure 13A The components of the optical system 1015 shown herein can be referenced. Figures 1 to 10C The components of the described optical systems and devices are similar or identical. Optical system 1015 may include a focal plane array (FPA) unit 1008 configured to record infrared image data captured by system 1000. Figure 13AAs shown, the FPA unit 1008 can advantageously not be cooled, for example, without a cooling system.

[0232] Optical system 1015 may include a front window 1006 through which light from object 1007 passes. A first movable blackbody source 1003 and a second movable blackbody source 1004 may be provided to calibrate optical system 1015. The movable sources 1003 and 1004 can be moved in front of the field of view, allowing optics to image these sources for calibration. For example, the first blackbody source 1003 and the second blackbody source 1004 may be stably maintained at different known temperatures. For example, heaters and temperature sensors may be attached to each blackbody source 1003 and 1004 to provide feedback, thereby creating a stable and known temperature difference (e.g., at least 50 mK in some arrangements) between different spatial regions of the sources.

[0233] Furthermore, the optical system 1000 may include a dynamic calibration device to dynamically calibrate the system 1000. For example... Figure 13A As shown, one or more calibration sources 1009, 1010 may be provided. Calibration sources 1009, 1010 may include thermoelectric control (TEC) material to which a temperature sensor is attached. Calibration sources 1009, 1010 may be coated with a spectral measurement coating or paint. Light from calibration sources 1009, 1010 may be reflected from one or more mirrors 1005 and guided through lens array 1002 (described below) to image a portion of FPA unit 1008, thereby facilitating dynamic calibration system 1000 (e.g., when imaging of a target gas cloud is simultaneously performed).

[0234] The optical system 1000 may include a lens array 1002 to focus incident light onto the FPA unit 1008. For example... Figure 13A As shown, each lens in the lens array 1002 may at least partially define or be included in the optical path to be imaged by the FPA unit 1008. To improve the mobility and portability of the mobile imaging system 1000, the lens array 1002 may include integrated units formed from or assembled into a single monolithic body. Such an integrated lens array 1002 can reduce the size of the imaging system 1015, and thus the size of the system 1000, to at least partially enable the system 1000 to be worn or carried by a user. The lens array 1002 may be integrally formed in any suitable manner. For example, in various embodiments, the lens array 1002 may be formed by a diamond milling tool. In some embodiments, the lens array 1002 may include a monolithic transparent material having separation regions shaped as curved refractive surfaces to produce separate lenses. In some embodiments, lenses may be inserted into an array of openings formed in a plate or substrate to produce the lens array 1002.

[0235] The optical system 1000 may also include an array of infrared (IR) filters 1001, which is configured to filter the wavelength of infrared light in an appropriate manner. For example, regarding Figures 5A to 6D This article discloses examples of IR filters and filtering techniques. For example... Figure 13A As shown, an IR filter 1001 may be disposed between a lens array 1002 and an FPA unit 1008. The IR filter 1001 may at least partially define multiple optical channels to be imaged by the FPA unit 1008. In some embodiments, the IR filter 1001 may be positioned between the lens array 1002 and a first movable blackbody source 1009 and a second movable blackbody source 1010.

[0236] Figure 13B This is a schematic system diagram of an optical system 1015 according to various embodiments, configured for use in the mobile infrared imaging system 1000 disclosed herein. As explained herein, Figure 13B The optical system 1015 shown can be incorporated into the data acquisition and processing module 1020, which is worn or carried by the user. Figure 13B The components of the optical system 1015 shown herein can be compared with those described herein. Figures 1 to 10C and Figure 13A The components of the optical systems and devices described are similar or identical.

[0237] Figure 13B The optical system 1015 may include an FPA unit 1408 configured to image an object 1409 (such as a gas cloud or chemical spill). As... Figure 13A The implementation scheme shown, Figure 13B The system 1015 may include a front window 1406 through which light from object 1409 passes, a first movable blackbody source 1403 and a second movable blackbody source 1404, an IR filter array 1401, and a lens array 1402. As... Figure 13A In one implementation scheme, the lens array 1402 may include an integral main body or a single-piece main body. Figure 13B In one embodiment, the lens array 1402 may be disposed between the filter array 1401 and the FPA unit 1408. In other arrangements, the filter array 1401 may be disposed between the lens array 1402 and the FPA unit 1408.

[0238] Figure 13B The optical system 1015 may include a cooling unit 1430 configured to cool the FPA array 1408. The cooling unit 1430 may include cooling fingers configured to cryogenically cool the FPA array 1408 in various arrangements. Figure 13B As shown, filter array 1401, lens array 1402, and FPA unit 1408 can be disposed in the cooling region 1440. Blackbody sources 1403, 1404, and front window 1406 can be disposed in the uncooled region 1450. Placing blackbody sources 1403, 1404 at an uncooled temperature and filter array 1401, lens array 1402, and FPA unit 1408 at a cooled temperature can facilitate the periodic calibration of system 1000.

[0239] Figure 14A This is a schematic perspective view of a mobile infrared imaging system 1000 (e.g., a mobile DAISI system) mounted on a helmet 1200 according to various implementation schemes. Figure 14B yes Figure 14A The diagram shows an enlarged schematic perspective view of the mobile infrared imaging system 1000. The helmet 1200 may include part of the user's personal protective equipment and can also advantageously serve as a platform for the imaging system 1000. As explained above, the helmet 1200 can be worn by a user when visiting a specific installation site to be monitored (such as an oil well site, refinery, etc.). The system 1000 can be activated to continuously monitor and analyze the site visited by the user. Therefore, the system 1000 can continuously and actively search for gas leaks anywhere the user visits, and if a leak is detected, it can trigger an alarm or other notification.

[0240] exist Figure 14B In the illustrated embodiment, the imaging system 1000 may include a housing 1590, within which or on which a data acquisition and processing module 1020 is mounted or connected (see, for example...). Figure 12 (and related descriptions). The support member 1592 may be coupled to or formed with the housing 1590 and may be configured to attach to the helmet 1200 or any other suitable platform. For example, in some embodiments, the support member 1592 may include one or more mounting holes for attachment to the helmet 1200 by means of, for example, screws, bolts or other fasteners. Additionally, as... Figure 14B As shown, a front window 1506 may be disposed at the front end of housing 1590. The front window 1506 may be transparent to IR radiation and may at least partially define the aperture of system 1000. In some embodiments, window 1506 comprises germanium. A diamond-based coating (DLC) or other coating or layer may be disposed on window 1506 to provide a durable surface.

[0241] As explained herein, system 1000 can be configured to be worn or carried by a human user. Therefore, the size of data acquisition and processing module 1020 is appropriately set to allow the user to easily wear or carry system 1000. For example, data acquisition and processing module 1020 can be at least partially defined by dimensions X×Y×Z, such as... Figure 14A and Figure 14B As shown.

[0242] Unlike other systems with bulky components or assembled with a large form factor, the size and shape of the mobile system 1000 can be configured to allow for easy movement and manipulation by a user as they move around the site. In practice, integrating various system components with a small form factor can be very challenging. Advantageously, the system 1000 disclosed herein can be worn or carried by a human user. For example, the components of the system 1000 can be housed together in a data acquisition and processing module 1020, which may include a housing 1590 to support the system components. The components of the system 1000 (including optical or imaging components, focal plane arrays, onboard processing electronics, and communication components) can be packaged or assembled in the data acquisition and processing module 1020 and can occupy a volume of less than about 300 cubic inches, less than about 200 cubic inches, or less than about 100 cubic inches. In various embodiments, components of system 1000 (including optical or imaging components, focal plane arrays, airborne processing electronics, and communication components) may be packaged or assembled in data acquisition and processing module 1020 and may occupy a volume greater than about 2 cubic inches or greater than about 16 cubic inches. In some embodiments, components of system 1000 (including optical or imaging components, focal plane arrays, airborne processing electronics, and communication components) may be packaged or assembled in data acquisition and processing module 1020 and may occupy a volume ranging from about 4 cubic inches to about 15 cubic inches. In some embodiments, components of system 1000 (including optical or imaging components, focal plane arrays, airborne processing electronics, and communication components) may be packaged or assembled in data acquisition and processing module 1020 and may occupy a volume ranging from about 5 cubic inches to about 12 cubic inches. In some embodiments, components of system 1000 (including optical or imaging components, focal plane arrays, onboard processing electronics, and communication components) may be packaged or assembled in data acquisition and processing module 1020 and may occupy a volume ranging from about 4 cubic inches to about 6.5 cubic inches, for example, about 5.63 cubic inches in one embodiment. In some embodiments, components of system 1000 (including optical or imaging components, focal plane arrays, onboard processing electronics, and communication components) may be packaged or assembled in data acquisition and processing module 1020 and may occupy a volume ranging from about 9 cubic inches to about 13 cubic inches, for example, about 11.25 cubic inches in one embodiment. In some embodiments, components of system 1000 (including optical or imaging components, focal plane arrays, onboard processing electronics, and communication components) may be packaged or assembled in data acquisition and processing module 1020 and may occupy a volume ranging from about 6 cubic inches to about 10 cubic inches.

[0243] The size and shape of the data acquisition and processing module 1020 (wherein or on which system components are mounted) may be configured to fit within a frame boundary having dimensions X×Y×Z. For example, the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be included in a package whose size and shape are configured to fit within a frame boundary having dimensions X×Y×Z. The package may also include a power supply, such as a battery and / or a solar module. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be configured to fit within a frame boundary smaller than 8 inches × 6 inches × 6 inches. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be configured to fit within a frame boundary smaller than 7 inches × 5 inches × 5 inches. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be configured to fit within a frame boundary smaller than 6 inches × 4 inches × 4 inches. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be configured to fit within a frame boundary smaller than 6 inches × 2 inches × 2 inches. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be configured to fit within a frame boundary having dimensions greater than 4 inches × 2 inches × 2 inches. In some embodiments, the size and shape of the data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may be configured to fit within a frame boundary having dimensions greater than 2 inches × 1 inch × 1 inch. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a size of less than 3 inches × 2 inches × 2 inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a size greater than 1 inch × 0.5 inches × 0.5 inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of less than 30 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of less than 20 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of less than 15 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume of less than 10 cubic inches.The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume exceeding 1 cubic inch. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume exceeding 4 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume exceeding 5 cubic inches. The data acquisition and processing module 1020 (including imaging optics, a focal plane array, and onboard processing electronics) may have a volume exceeding 10 cubic inches. The package may also include a power supply (including a battery and / or a solar module), a communication module, or both, and conform to the dimensions mentioned above. It should be understood that the dimensions disclosed herein may not correspond to specific dimensions. Figure 11A The orientations of X, Y, and Z are shown in the diagram. The package may also contain a power source (including a battery and / or solar module), a communication module, or both, and conform to the dimensions mentioned above. It should be understood that the dimensions disclosed herein may not correspond to... Figure 11A Regarding the directions indicated by X, Y, and Z.

[0244] In some implementation schemes, Figure 14B The dimension X shown can range from about 2 inches to about 7 inches, or more specifically, from about 2 inches to about 4 inches, for example, about 2.5 inches in one embodiment. In some embodiments, Figure 14B The dimension X shown can range from approximately 4 inches to approximately 6 inches, for example, approximately 5 inches in one embodiment. In some embodiments, Figure 14B The dimension Y shown can range from about 1 inch to about 5 inches, or more specifically, from about 1 inch to about 3 inches, for example, about 1.5 inches in one embodiment. In some embodiments, Figure 14B The dimension Z shown can range from about 1 inch to about 5 inches, or more specifically, from about 1 inch to about 3 inches, for example, about 1.5 inches in one embodiment.

[0245] Furthermore, the system 1000 may have a sufficiently small mass and weight to allow the user 1275 to easily carry or wear the data acquisition and processing module 1020 at the site. For example, the weight of the system 1000 may be in the range of about 0.5 pounds to 5 pounds, or more specifically, in the range of about 0.5 pounds to 2 pounds, or more specifically, in the range of about 0.25 pounds to about 2 pounds, or more specifically, in the range of about 0.25 pounds to about 1.5 pounds. For example, in one embodiment, the system 1000 may weigh about 1 pound. For example, in another embodiment, the system 1000 may weigh about 0.5 pounds. Therefore, Figure 11AThe dimensions and shape of the illustrated embodiment can be set and configured to have a mass that allows human users to easily and effectively operate the system 1000.

[0246] Figure 14C yes Figures 14A to 14B The diagram shows a perspective cross-sectional view of a mobile infrared imaging system 1000. The mobile infrared imaging system 1000 may include one or more movable shutters 1503 (e.g., two shutters) behind a window 1506 and a lens assembly 1502 behind one or more shutters 1503. A filter array 1501 may be disposed behind (or in front of) a second lens array 1502B, and an optical focal plane array (FPA) unit 1508 may be disposed behind the filter array 1501. The optical FPA unit 1508 may be mechanically and electrically coupled to one or more substrates 1586, which may include a printed circuit board or PCB substrate. In various embodiments, the FPA unit 1508 includes a single FPA or detector array. Additionally, as explained herein, the lens assembly 1502, filter array 1501, and optical FPA unit may at least partially define one or more optical channels that are spatially and spectrally distinct. The number of optical channels may be at least 4, at least 5, at least 8, at least 9, at least 12, at least 13, or at least 20. In some implementations, the number of optical channels is between 4 and 50.

[0247] One or more batteries 1588 may power system 1000 via one or more substrates 1586. Furthermore, a visible light imaging sensor 1580 may be disposed within housing 1590 and configured to provide a visible light image of the scene captured by system 1000. Processed IR image data may be superimposed on the visible light image. In various embodiments, the visible light imaging sensor 1580 may be used to reduce detection errors caused by scene motion, such as detecting moving objects (like animals or people) entering the field of view that will interfere with the collected data.

[0248] As explained herein, one or more movable shutters 1503 may be configured to provide spectral radiometry calibration of system 1000. One or more shutters 1503 may be configured to periodically move in and out of the field of view of lens assembly 1502 (e.g., within a range of about 1 minute to about 15 minutes, or more specifically within a range of about 3 minutes to about 7 minutes, such as a time period of about 5 minutes). Although in Figure 14C One shutter 1503 is shown, but it should be understood that two or more shutters may be provided. One or more shutters 1503 may be used in a static calibration procedure to provide absolute temperature values ​​for the system. In some embodiments, only static calibration is performed, for example, dynamic calibration is not performed. In some embodiments, both static and dynamic calibration procedures are performed simultaneously.

[0249] Lens assembly 1502 may include a first lens array 1502A and a second lens array 1502B. In some embodiments, lens assembly 1502 may include an array of two portions of lenses represented by the first array and the second array 1502A, 1502B. In some embodiments, lens assembly 1502 may include an array of two individual lenses represented by the first array and the second array 1502A, 1502B. Each of lens arrays 1502A, 1502B may include a 4×3 lens array, each lens array may correspond to a specific detector region in FPA unit 1508 and may define an optical path of system 1000. The lenses used in the first lens array 1502A may be different from the lenses used in the second lens array 1502B. These lenses may be any suitable type of lens, including, for example, spherical lenses, aspherical lenses, cylindrical lenses, etc., or any combination thereof. For example, the lenses used in the first lens array 1502A may include aspherical lenses, and the lenses used in the second lens array 1502B may include cylindrical lenses. Although Figure 14C The lens assembly 1502 shown includes two lens arrays, but it should be understood that additional lens arrays, such as three, four, or five lens arrays, may be used. Furthermore, to facilitate a small system size, the diameter of each lens in assembly 1502 may be less than about 0.5”, for example, in the range of about 0.1” to about 0.5”. The f-number of each lens may be less than about 2, for example, in the range of about 0.2 to 2, or more specifically in the range of about 0.5 to 2, or 1.0 to 2, or 1.1 to 2.

[0250] A first lens array 1502A and a second lens array 1502B may be coupled to each other via a mounting plate 1584, the size and shape of which are configured to support or receive each lens array 1502A, 1502B. For example, the first lens array 1502A may be mounted on one side of the mounting plate 1584, and the second lens array 1502B may be mounted on the opposite side of the mounting plate 1584. The mounting plate 1584 may be machined to have a diameter tolerance of approximately + / - 25 micrometers. The lenses of arrays 1502A, 1502B may be fixed to the mounting plate 1584 using a curable epoxy resin. For example, the lenses may fit into opposite sides of holes formed in the mounting plate 1584.

[0251] The optical FPA unit 1508 may include any suitable type of detector array configured to detect, for example, infrared radiation with wavelengths greater than 1 micrometer, or greater than 2 micrometer, or greater than 3 micrometer, or greater than 5 micrometer, or greater than 6 micrometers and possibly less than 20 micrometers, or 15 micrometers, or 13 micrometers, or 12 micrometers, or 10 micrometers, and may be cooled or uncooled. In some embodiments, the optical FPA unit 1508 includes one or more microbolometer arrays, which may be uncooled. For example, one of approximately 1000 × 1000 microbolometer arrays may be used in the embodiments disclosed herein. Microbolometer arrays (such as those manufactured by DRS Technologies, Arlington, Virginia and Sofradir EC, Inc., Fairfield, New Jersey) may be suitable for the embodiments disclosed herein. For example, the DRS U8000 FPA manufactured by DRS Technologies may be used in some embodiments. In some arrangements, the microbolometer array may have a resolution of 1024 × 768 and a pixel pitch of 12 micrometers. Lens arrays may form individual channels, each with an image detection area forming part of the array. For example, 12 channels may be comprised of a 1024 × 768 pixel array on a detector array (microbolometer array), which is, for example, 250 × 250 pixels for each of the 12 channels. Detector arrays with more or fewer pixels may be employed. Similarly, the number of channels may be greater than or less than 12, and the detection area on the detector array for a single channel may be greater than or less than 250 × 250 pixels. For example, the detection area may comprise 100-200 pixels × 100-200 pixels per detection area. For example, the detection area may include 100-200 pixels × 100-200 pixels / detection area, 200-300 pixels × 200-300 pixels / detection area, or 300-400 pixels × 300-400 pixels, or 400-500 pixels × 400-500 pixels. Similarly, the detection area for one channel may have 100-200 pixels on one side, 200-300 pixels on one side, 300-400 pixels on one side, 400-500 pixels on one side, or larger or smaller.

[0252] In some arrangements, the spectral band of the microbolometer can be from about 7.5 micrometers to 14 micrometers, or from about 3 micrometers to 14 micrometers, or from 3 to 8 micrometers. The microbolometer array can operate at a frame rate of about 30 Hz and can operate at an operating temperature of about -40°C to +70°C. In various embodiments, the microbolometer array is an uncooled microbolometer without a cooler. The sensitivity of the microbolometer at F / 1 can be < about 40 mK. The system 1000 disclosed herein can be used to detect wavelengths in the range from about 1 micrometer to about 20 micrometers. For example, the system 1000 disclosed herein can be used to detect wavelengths above about 6 micrometers, such as in the range from 6 micrometers to about 18 micrometers, in the range from about 3 micrometers to about 14 micrometers, or more specifically in the range from about 7 micrometers to about 14 micrometers, or from 3 to 8 micrometers. In various embodiments, the individual detector elements of the microbolometer array can be spaced apart in a relatively close manner to at least partially realize a small, compact system. For example, adjacent detector elements of the array may be spaced apart in the range of about 7 micrometers to about 15 micrometers, or more specifically in the range of about 9 micrometers to about 13 micrometers, for example, a distance of about 11 micrometers. Individual lenses may be spaced apart in the range of about 20 mm to about 35 mm, for example, in the range of about 24 mm to about 30 mm, for example, a distance of about 27.5 mm. Similarly, channels that are spatially and spectrally separated may be physically spaced apart by 20 mm to 35 mm, 24 mm to 30 mm, etc. Although various embodiments of the system are described as including an FPA having, for example, a microbolometer array, some embodiments include multiple FPAs. In some embodiments, a single optical FPA is used. In some embodiments, the detectors of the optical FPA are configured to detect radiation in the same IR wavelength band.

[0253] The onboard processing electronics of the data acquisition and processing module 1020 can process IR optical data to detect and / or identify target substances from IR radiation received at the optical FPA. For example, module 1020 can be configured to acquire multispectral image data and analyze the acquired image data to identify target substances. For example, the mobile imaging system 1000 disclosed herein can be configured to image a 10m × 10m object area at a distance of approximately 17m with a resolution of approximately 0.04m. In this embodiment, system 1000 can detect and / or identify any gas leaks that generate gas clouds of at least approximately 1.5 inches in size. The detection and identification methods can be performed substantially in real time, enabling the user to be alerted upon identification of any leaks.

[0254] As explained above, the infrared image data captured by the imaging system 1000 can be processed on-board at the data acquisition and processing module 1020 of the imaging system 1000. One way to provide a smaller system 1000 is to use one or more field-programmable gate arrays (FPGAs) to process the image data, wherein the one or more FPGAs are configured to perform methods used in the analysis of images captured by the optical system 1015. In some embodiments, one or more application-specific integrated circuits (ASICs) may be used to replace or supplement the FPGA. For example, an ASIC chip may include an FPGA. The FPGA (and / or ASIC) may be mounted to... Figure 14C The substrate 1586 shown is electrically coupled to the substrate and can be physically positioned near the optical system. For example, the FPGA may include logic gates and read-access memory (RAM) blocks designed to rapidly perform calculations for detecting gas types in gas clouds. The small size / weight and high performance of the FPGA enable onboard computing and analysis within the user-worn or carried data acquisition and detection unit 1020. The use of an onboard FPGA (or similar electronics) in system 1000 reduces the costs associated with image analysis calculations using off-site central servers or larger computing devices. Advantageously, the embodiments disclosed herein enable onboard computing, even though implementing complex methods on the limited computing platform provided by an FPGA can be challenging.

[0255] Furthermore, performing computations using one or more FPGA devices onboard the wearable system can prevent or reduce communication bottlenecks associated with wirelessly transmitting large amounts of raw data from System 1000 to a remote server or computer. For example, the infrared optical system 1015 disclosed herein can generate up to approximately 380 Mbps of raw image data at 30 frames per second, and the visible light sensor 1580 can generate approximately 425 Mbps of raw image data at 30 frames per second. The resulting data rate of approximately 800 Mbps is faster than most conventional wireless technologies. While data compression and / or preprocessing can reduce the raw data rate of visible light and IR images, in some embodiments, IR image data may only be compressed at a ratio of approximately 2:1. The resulting total data rate of approximately 192 Mbps may not be efficiently transmitted by conventional wireless communication devices. Therefore, performing image processing computations onboard on System 1000 (e.g., on the data acquisition and processing module 1020) can reduce the need for wireless transmission of raw image data to an off-site central server or avoid the resulting bottlenecks.

[0256] One challenge in implementing a mobile imaging system is the power requirements of each component of the system, including, for example, the IR optics system 1015, the visible light sensor 1580, processing electronics, wireless communication modules, etc. Advantageously, the mobile infrared imaging system 1000 disclosed herein can be configured to operate for extended periods powered by battery without requiring recharging or replacement of the battery 1588. In some arrangements, the one or more batteries 1588 may comprise lithium-ion batteries with relatively high energy density. Furthermore, to help reduce power consumption within the system 1000, the FPGA of the data acquisition and processing module 1020 can be advantageously programmed to consume less power than that used for other types of processing electronics.

[0257] The system 1000 disclosed herein can advantageously operate for 8 to 36 hours without recharging or replacing the battery, or more specifically, for about 10 to 24 hours without recharging or replacing the battery. In some embodiments, the system 1000 can operate for at least about 12 hours without recharging or replacing the battery. Components of the data acquisition and processing module 1020 (including imaging optics, focal plane array, and onboard processing electronics) can be configured to operate at relatively low power levels, for example, in the range of about 3W to about 10W, or more specifically in the range of about 4W to about 7W, or in the range of about 4W to about 6W, for example, at a power level of about 5W in some embodiments. The components of the data acquisition and processing module 1020 (including imaging optics, focal plane array, and airborne processing electronics) can also be configured to operate at a relatively low total energy level of a single charge of the battery 1588, for example, in the range of about 60 watt-hours (Wh) to about 100 Wh, or more specifically in the range of about 80 Wh to about 95 Wh, or in the range of about 85 Wh to about 90 Wh.

[0258] Furthermore, for each embodiment disclosed herein, various motion detection and / or compensation techniques can be implemented to account for relatively large-scale movements caused by a user moving their head during use. For example, when a user visits an oil well site or other facility, the user may continuously walk and observe in different directions (e.g., by rotating their head). Additionally, the user's natural instability can cause vibrations. Such movements can continuously change the system's field of view at a relatively rapid rate, which can affect the accuracy of methods used to determine the type of matter in gas clouds or other objects. Therefore, it may be desirable to provide improved motion detection and / or compensation techniques to reduce errors associated with user movement.

[0259] IV. Additional Examples of Mobile DAISI Systems

[0260] This section provides additional implementations of a mobile segmented aperture infrared spectroscopy imaging (DAISI) system. For example, Figures 15A to 24D The system 1000 shown can be used with any of the embodiments disclosed above, including, for example... Figures 11A to 14C The illustrated implementation scheme of the mobile DAISI system 1000. Furthermore, Figures 15A to 24D The imaging components used can be with Figures 1 to 10C It can be used in combination with any implementation scheme. Advantageously, the system 1000 disclosed herein can provide various improvements that enable the multispectral snapshot mode imaging system to be worn or carried by a person.

[0261] Similar to the implementation plan mentioned above, Figures 15A to 24D The system 1000 may include an optical focal plane array (FPA) and components defining at least two optical channels that are spatially and spectrally distinct from each other. The at least two optical channels may be positioned to redirect infrared (IR) radiation toward the FPA. A processing unit, including a processor and / or processing electronics, may acquire multispectral image data representing a target substance from the received IR radiation. The optical system and processing unit may be included together in a data acquisition and processing module configured to be worn or carried by a person. In some embodiments disclosed in this section, the imaging system may be fixed at a desired location, such as at an oil refinery, oil well site, etc.

[0262] A. System Overview

[0263] Figure 15A This is a schematic perspective view of system 1000 according to various implementation schemes. Figure 15B yes Figure 15A The diagram shows a schematic rear perspective view of system 1000. System 1000 may include a data acquisition and processing module 1020, which may be similar to the data acquisition and processing module described above. For example, data acquisition and processing module 1020 may include a housing 1640 that houses the optical components of system 1000. System 1000 may include an optical window 1606 and a visible light imaging system 1680. Window 1606 may be configured to transmit infrared radiation from an object to internal optical components within housing 1640. In some embodiments, window 1606 comprises germanium. Window 1606 and visible light imaging system 1680 may be the same as or similar to the window and visible light system described above.

[0264] like Figure 15BAs shown, the data acquisition and processing unit 1020 may include any suitable number of power and / or signal connections to the computing device. For example, the data acquisition and processing unit 1020 may include a data connector 1681 to provide data communication between the data acquisition and processing unit 1020 and the computing device. The data acquisition and processing unit 1020 may also include a power connector 1682 to provide electrical power to the data acquisition and processing unit 1020. In some arrangements, the data acquisition and processing unit 1020 may include a communication module 1024 that provides wireless (and / or wired) data communication with external computing devices such as laptop computers, tablet computers, smartphones, etc. Furthermore, the data acquisition and processing unit 1020 may include one or more batteries to power the system 1000.

[0265] The data acquisition and processing unit 1020 can be configured to be worn or carried by a person. The combination of components described herein advantageously allows the optical components and processing electronics to be fitted within a small form factor suitable for human wear or carrying. For example, the data acquisition and processing unit 1020 may have a size and weight (or mass) chosen to allow a human user to easily wear or carry it to any suitable location, such as for infrared imaging and monitoring of potential gas leaks at oil facilities. Figure 15A As shown, the size and shape of the data acquisition and processing unit 1020 can be configured to fit within a frame boundary having dimensions X × height Y × width Z. The volume of the data acquisition and processing unit 1020 can range from 5 cubic inches to 40 cubic inches, from 9 cubic inches to 30 cubic inches, from 10 cubic inches to 30 cubic inches, from 10 cubic inches to 25 cubic inches, from 10 cubic inches to 20 cubic inches, or from 10 cubic inches to 15 cubic inches. In some embodiments, the volume of the data acquisition and processing unit 1020 can range from 15 cubic inches to 25 cubic inches, from 17 cubic inches to 24 cubic inches, or from 19 cubic inches to 23 cubic inches.

[0266] Length X can range from 3 inches to 8 inches, from 3.5 inches to 6 inches, from 4 inches to 6 inches, or from 5 inches to 6 inches. Height Y can range from 1 inch to 5 inches, from 1 inch to 3 inches, from 1.5 inches to 2.5 inches, or from 2 inches to 2.5 inches. Width Z can range from 1 inch to 5 inches, from 1 inch to 3 inches, from 1 inch to 2.5 inches, or from 1 inch to 2 inches. For example, width Z can range from 1.25 inches to 2 inches, from 1.5 inches to 2 inches, or from 1.6 inches to 1.9 inches.

[0267] The data acquisition and processing unit 1020 can weigh between 0.5 lbs and 5 lbs, between 0.5 lbs and 3 lbs, between 0.75 lbs and 2.5 lbs, between 1 lb and 2.5 lbs, between 1 lb and 2 lbs, or between 1.25 lbs and 1.75 lbs.

[0268] Figure 15C This is a schematic front perspective view of system 1000 according to various implementation schemes. Figure 15C The components of System 1000 can be used with Figures 15A to 15B The components are the same. However, Figure 15C Implementations may include enclosure 1640A, configured for use in conjunction with locations classified as Class 1, Zone 1 of the National Electrical Code (NEC) (available at necconnect.org). For example, Figure 15C The housing 1640A can be fully sealed to prevent gas from entering the housing 1640A. As another example, Figure 15C The housing 1640a can be of a type typically considered explosion-proof. The processing electronics and other components within the data acquisition and processing unit 1020 can be passively cooled without requiring external airflow from the external environment (e.g., ambient air) into the data acquisition and processing unit 1020. In some embodiments, the data acquisition and processing unit 1020 may be filled with a gas to cool the internal components. For example, in some embodiments, the data acquisition and processing unit 1020 and the housing 1640A may be filled with nitrogen. Figure 15C The system 1000 shown can be fixed in a permanent location (e.g., an oil well site or other oil facility) or can be configured for use by mobile users (e.g., worn or carried by the user).

[0269] Figure 15D This is a schematic system illustration of a mobile computing device 1600 having a first port 1602 configured for electrical coupling and physical connection to a DAISI system 1000 (such as any mobile DAISI system disclosed herein). The mobile computing device 1600 can be any suitable type of mobile computing device, for example, a computing device configured to be worn or carried by a person. For example, the mobile computing device 1600 may include a mobile smartphone, a tablet computing device, a laptop computer, etc.

[0270] The DAISI system 1000 may include a data acquisition and processing unit 1020 as described herein. The data acquisition and processing unit 1020 may be housed in and / or coupled to a housing 1640B. The DAISI system 1000 may include an optical system 1610 housed in the data acquisition and processing unit 1020 and / or the housing 1640B. The optical system 1610 may include various optical components of the DAISI system that cooperate to acquire multispectral image data, including, for example, optical filters, lenses, and optical detectors. For example, the optical system 1610 may include multiple spectrally and spatially distinct optical channels along which infrared radiation can be transmitted to the detector.

[0271] In some embodiments, the data acquisition and processing unit 1020 and / or housing 1640B may include a processing unit 1611 having a processing circuitry configured to analyze the acquired image data to detect and / or identify target substances. In an illustrated embodiment, the processing unit 1611 for analyzing the acquired image data is disposed within and / or coupled to the data acquisition and processing unit 1020 and / or housing 1640B. However, in other embodiments, the processing unit 1611 may be disposed within the mobile computing device 1600 and may form part of the mobile computing device.

[0272] The data acquisition and processing unit 1020 and / or housing 1640B may include a second port 1603 configured to mate with a first port 1602 of the mobile computing device 1600. Ports 1602 and 1603 may be any suitable type of data and / or power port. For example, ports 1602 and 1603 may include ports used as conventional power ports, audio ports, or other ports on mobile smartphones and / or tablet computing devices. In various embodiments, ports 1602 and 1603 may conform to various industry standards, such as Universal Serial Bus (USB) standards (e.g., USB Type-C, USB 3.1, etc.) available at usb.org. As another example, ports 1602 and 1603 may be wireless communication ports utilizing any desired wireless technology (e.g., via Bluetooth, WiFi, etc.), enabling the mobile computing device 1600 and the DAISI system 1000 to communicate even without a physical connection.

[0273] Advantageously, Figure 15DThe arrangement shown allows a user to obtain a plug-and-play mobile DAISI system 1000 and to removably connect the system 1000 to his or her personal mobile computing device 1600. The system 1000 may be pre-loaded with software instructions that cooperate with the operating system of the mobile computing device 1600 to operate the optical and processing components of the mobile computing device 1600. In other arrangements, the user may download software to the mobile computing device 1600, and the downloaded software instructions may control the operation of the DAISI system 1000. In some embodiments, the DAISI system 1000 includes both optical components and processing electronics (e.g., a data acquisition and processing unit 1020), enabling the system 1000 to perform image acquisition and data processing to detect and / or identify target substances. The system 1000 may transmit data about detected and / or identified substances to the mobile computing device 1600, which may display this information to the user through a suitable user interface (e.g., a display and / or a speaker). In some implementations, the DAISI system 1000 may include a user interface (e.g., a display and / or a speaker) such that the system 1000 can directly alert the user to detected and / or identified substances even when the mobile computing device 1600 is not coupled to the DAISI system 1000. As an example only, the DAISI system 1000 may include a display (such as a flashlight and / or a speaker) that alerts the user (i.e., provides an alarm) when one or more target substances are detected and / or when one or more target substances are detected at concentrations greater than a predetermined threshold concentration.

[0274] In other embodiments, the DAISI system 1000 may include only optical components (e.g., optical windows, multiple optical filters, multiple lenses, and optical detectors), and processing electronics may be housed within a mobile computing device 1600. In such an arrangement, the DAISI system 1000 may be configured to acquire image data from a scene (with or without preprocessing techniques) and may transmit the acquired image data to the mobile computing device 1600. The processing electronics of the mobile computing device 1600 may be configured with software instructions that, when executed by the processing electronics, process the acquired image data to detect and / or identify one or more target substances. The detected and / or identified target substances may be transmitted to a user via a user interface (e.g., a display and / or a speaker). In some embodiments, the housing may include an optical system and a processing unit with a processing circuitry configured to analyze the acquired image data to detect and / or identify target substances.

[0275] Therefore, in various embodiments, the DAISI system 1000 may include a housing 1640B in which the optical system 1610 is disposed. The optical system 1610 may include the optical components described herein, including, for example, an optical detector and optical components (such as multiple filters and multiple lenses spaced apart from the filters) defining multiple optical channels that are spectrally and spatially distinct. Each of these multiple optical channels may be positioned to deflect IR radiation incident on the optical system 1610 toward the optical detector, as explained herein. A second port 1603 may be in data communication with the optical detector and is configured to be electrically and physically connected to the mobile computing device 1600 to transmit image data acquired by the optical detector to the mobile computing device 1600. Additionally, the housing 1640B may include an electronic circuitry system 1616 in communication with the second port 1603. The electronic circuit system 1616 can be configured to receive instructions from or transmit instructions to the mobile computing device 1600, thereby instructing the mobile computing device 1600 to be electrically and physically connected, for example, via a first port 1602 and a port 1603.

[0276] The electronic circuitry system 1616 of the housing can be configured to verify an identifier transmitted from the mobile computing device 1600 to authenticate that the mobile computing device 1600 is authorized to receive the acquired image data. For example, when a user connects the second port 1603 to the first port 1602, the corresponding circuitry system in the mobile computing device 1600 can send an identifier to the electronic circuitry system of the housing to request access to the captured image data and verify the authenticity of the user associated with the mobile computing device 1600. If the electronic circuitry system 1616 verifies the mobile computing device 1600, the electronic circuitry system 1616 may include a switching circuitry system that allows the acquired image data to be passed to the mobile computing device 1600 through the port. In some embodiments, the electronic circuitry system 1616 may be part of a processing unit 1611.

[0277] therefore, Figure 15D The system 1000 shown can be sufficiently miniaturized for use in small mobile computing devices, such as mobile smartphones and tablet computers. In various embodiments, for example, the volume of the housing 1640B, in which the optical system 1610 and the processing unit 1611 are disposed, can range from 0.25 cubic inches to 10 cubic inches, from 0.25 cubic inches to 8 cubic inches, from 0.5 cubic inches to 8 cubic inches, from 0.5 cubic inches to 5 cubic inches, from 0.5 cubic inches to 3 cubic inches, or from 0.5 cubic inches to 2 cubic inches.

[0278] System 1000 can be miniaturized in various ways. In some embodiments, the optical system and / or processing unit can be fabricated using wafer-level or chip-level processing techniques. For example, as explained in Section IV.E.1 herein, the filter array of the optical system can be patterned using semiconductor processing techniques such as deposition, lithography, and etching. In some embodiments, the lens array and detector array can also be fabricated using such wafer-level or chip-level techniques.

[0279] Figure 15E This is a schematic system diagram of a mobile computing device 1600 according to another embodiment. Figure 15E In this case, the DAISI system 1000 is integrated within a housing 1640C, which defines the main body of the mobile computing device 1600. Figure 15E The mobile computing device 1600 may include any suitable type of mobile computing device, such as a mobile smartphone or tablet computer. The DAISI system 1000 and the mobile computing electronics 1601 may be housed together within the housing 1640C of the mobile computing device 1600. The DAISI system 1000 may include any mobile DAISI system disclosed herein. The mobile computing electronics 1601 may include processing electronics configured to control the operation of the conventional mobile computing device 1600. For example, the mobile computing electronics 1601 may include various communication platforms, including circuit systems configured to transmit and receive cellular data (e.g., voice data and / or multimedia data), wireless data packets, etc. The mobile computing electronics 1601 may include various other applications used in mobile devices such as mobile smartphones and / or tablet computers.

[0280] Figure 16A This is a schematic diagram of a DAISI system 1000 that can be used according to any implementation disclosed herein. Figure 16A The system 1000 may include an optical system 1610 electrically connected to the processing unit 1611. Figure 16A A single optical channel 1626 is shown; however, system 1000 may include multiple optical channels 1626 that are spectrally and spatially different from each other, as explained herein. Optical system 1610 may include a filter 1620, a lens 1622 including multiple lens elements L1, L2, L3, an optical window 1623, and an optical detector 1624. Filter 1620 may include any filter described herein, which may be an infrared filter. Although in Figure 16A Only a single filter 1620 is shown in the document, but the DAISI system 1000 may include multiple filters that are spatially and spectrally different, and these filters may be arranged in a two-dimensional array as described herein.

[0281] The lens 1622 of the illustrated optical channel 1626 may include a plurality of lens elements L1, L2, L3, which are arranged adjacent to or relative to each other along the optical axis, for example, between the object 1625 (e.g., a cloud of gas) and the detector 1624. As explained herein, the dimensions of the lens elements L1, L2, L3 may be selectively set to improve the sensitivity of the optical system 1610 and improve image quality. Like the filter 1620, the plurality of lenses 1622 may be arranged in a two-dimensional array and may be arranged relative to or spaced apart from the filter along the optical axis. An optical window 1623 may be disposed behind the lens 1622, and the detector 1624 may be disposed behind the optical window 1623 and may be configured to convert acquired infrared image data into an electrical current. The detector 1624 may be any suitable type of detector, including those disclosed herein, such as an optical focal plane array (FPA). As an example, the detector 1624 may include one or more microbolometers. The detector 1624 may be electrically connected to the processing unit 1611. Variations in optical design are possible. For example, additional elements such as baffles and / or apertures may be included. Filters such as filter 1620 and other filters may be combined with lenses and / or windows.

[0282] Figure 16B This is a schematic front perspective view of the DAISI System 1000, with the housing removed for illustrative purposes only. Figure 16C yes Figure 16B A schematic rear perspective view of System 1000. (See diagram below.) Figure 16B and Figure 16C As shown, shutter 1621 may be located behind optical window 1606. As described below, shutter 1621 may include a rotary shutter that rotates to switch between one or more calibration modes and operational imaging modes. Optical system 1610 may be located behind shutter 1621, and processing unit 1611 may be located behind optical system 1610. Optical system 1610 may include the optical components described herein that enable the acquisition of multispectral infrared image data. Processing unit 1611 includes processing electronics that can be configured to process the acquired multispectral infrared image data to detect and / or identify target substances. For example, processing unit 1611 may include or resemble... Figure 12 And related publicly available content processing unit 1021.

[0283] exist Figure 16B as well as Figure 15CIn the example, the visible light imaging system 1680 is shown positioned close to (e.g., just above) the split aperture infrared spectroscopy imaging (DAISI) system. Other suitable arrangements may be provided if desired. As an example, the visible light imaging system 1680 may be omitted entirely. As another example, housing 1640A (see...) Figure 15C The system 1000 can be divided into two or more sections, one section of which may contain a visible light imaging system module, and another section of which may contain a DAISI system. This arrangement facilitates the maintenance of the system 1000, including the replacement of the visible light imaging system 1680 with another visible light imaging system according to the user's needs and expectations. As an example, the system 1000 can be provided to allow the user to replace at least a portion of the visible light imaging system 1680 with a system having a zoom lens. The system 1000 can facilitate this replacement by providing the visible light imaging system 1680, which is relatively separate from the DAISI system and / or contained in a separate section of the housing 1640A.

[0284] The visible light imaging system 1680 may include any desired focal length lens, including a zoom lens with a variable focal length. The zoom lens in the visible light imaging system 1680 may include actuators, motors, or other similar devices that drive lens elements within the zoom lens in response to control signals (typically generated locally by the circuitry in system 1000 or remotely by an external device and received by system 1000 via a communication channel) to adjust the focal length (e.g., magnification) of the lens.

[0285] Figure 16D This is a schematic front perspective view of the optical system 1610. (See attached image.) Figure 16D As shown, the optical system 1610 may include a shutter 1621, a support body 1626, and an optical detector 1624. Figure 16D In this structure, optical components such as filter 1620 and lens 1622 can be disposed in the support body 1626. Figure 16E This is a schematic perspective cross-sectional view of the optical system 1610, in which the shutter is omitted for illustrative purposes. Figure 16E The diagram shows an array of filters 1620 supported by a support body 1626 and lens elements L1, L2, and L3 of lenses 1622. (See diagram for reference.) Figure 16E As shown, the array of filters 1620 can be mounted within the aperture of the lens retainer 1627. Additional features of the optical system 1610 will be described in detail below.

[0286] like Figure 16EAs shown, lens element L1 can typically be located within a common plane. Similarly, lens elements L2, L3, and filter 1620 can typically be located within their own common plane. If desired, some or all of the optical components associated with one or more spectral channels (e.g., lens elements L1, L2, and L3, and filter 1620) can be offset from the optical components of the remaining spectral channels in a direction along the optical axis of system 1000 (i.e., in a direction perpendicular to the common plane). Generally, any channel can be offset by any amount in any direction (towards or away from the detector) as needed. As an example, the optical components of one or more channels can be offset closer to detector 1624 by approximately 10 micrometers, approximately 10-20 micrometers, approximately 20 micrometers, approximately 20-30 micrometers, approximately 30 micrometers, approximately 10-30 micrometers, approximately 10-50 micrometers, approximately 10-100 micrometers, greater than approximately 100 micrometers, less than 100 micrometers, less than 50 micrometers, less than 30 micrometers, greater than 30 micrometers, greater than 50 micrometers, etc. The optical components of one or more channels can also be offset from detector 1624 by a similar amount.

[0287] In at least some arrangements, the position of filter 1620 relative to lens elements L1, L2, and L3 can also be varied on a per-channel basis. As an example, for some channels, the first set of filters 1620 may be positioned after one or more of the lens elements L1, L2, and L3, while in other channels, the second set of filters 1620 may be positioned before the lens elements L2, L2, and L3.

[0288] Moving the optics of at least one spectral channel closer (or further away) from detector 1624 facilitates imaging of a wider or specific range of infrared wavelengths. In some embodiments, lenses for one or more spectral channels may be oriented approximately 20 micrometers toward detector 1624. Displacement of the lens position by approximately 20 micrometers allows these channels to be properly focused on incident IR radiation with wavelengths between 3 and 8 micrometers. The remaining (i.e., undisplaced) lenses can be properly focused on incident IR radiation with longer wavelengths of approximately 8 to 14 micrometers.

[0289] As an example, the four channels in the corner of System 1000 ( Figure 19The lens elements L1, L2, and L3 of channels 1, 4, 9, and 12 in the perspective view can be offset by approximately 20 micrometers from the other channels toward the infrared detector 1624. This offset of the four channels at the corners allows the offset channels to image objects with wavelengths different from the other channels (e.g., shorter). In particular, the offset channels can propagate shorter wavelengths of light. The refractive index of the materials used in L1, L2, and L3 may vary with wavelength. Therefore, the focal length of the imaging optics in these channels can be shorter. Without reducing the distance between the imaging optics and the detector array, the image will be out of focus. Similarly, by reducing this distance to the detector array, the image can be more focused. Therefore, this distance can be reduced by moving the lenses (e.g., L1, L2, L3) closer to the detector array, thereby providing better focus for shorter wavelengths such as those extending from 8 micrometers to 3 micrometers (e.g., compared to wavelengths from 8 micrometers to 14 micrometers). Thus, the offset along the optical axis can provide enhanced focusing for different wavelengths of infrared radiation incident on the detector 1624. Therefore, offsetting along the optical axis can reduce the focusing differences of channels operating at different wavelengths.

[0290] B. Rotary shutter

[0291] As mentioned above Figures 1 to 4 As explained above, providing one or more reference surfaces for the calibration of the DAISI system can be important. For example, as explained above, in some embodiments, the system disclosed herein can utilize one or more shutters having known and / or measured temperatures. To calibrate the system, one or more shutters (or other reference surfaces) can be positioned along the optical axis of the system, and an optical detector array can acquire infrared image data from the shutters. Measurements at the detector array can be used to estimate pixel gain and / or offset in order to accurately estimate the concentration of an object (such as a gas cloud). In some embodiments, as explained above, the system can utilize multiple shutters or surfaces at corresponding known and / or measured temperatures. The absolute temperature difference between the shutters or surfaces can be measured at the detector array, and as explained herein, the measured temperature difference can be used to measure the temperature at the object.

[0292] Figure 17A yes Figure 16B and Figure 16DThe illustrated shutter 1621 is a front plan view. The illustrated shutter 1621 may include a rotary shutter assembly configured to rotate about an axis parallel to the system's optical axis. The shutter 1621 (or shutter assembly) may include a shutter frame 1706 and a shutter body 1701 rotatably mounted to the shutter frame 1706. For example, the shutter 1621 may include a shaft 1705 disposed within a bore in the shutter frame 1706. A shutter drive system 1708 may be activated such that the shaft 1705 rotates about an axis parallel to the system's optical axis. The drive system 1708 may include any suitable drive components for imparting rotation to the shaft 1705. For example, the drive system 1708 may include a drive motor and one or more gears (or other clutch mechanisms) for imparting rotation to the shaft 1705. The shaft 1705 may be fixed to the shutter body 1701 such that rotation of the shaft 1705 imparts rotation to the shutter body 1701.

[0293] The shutter body 1701 may include a plurality of separate and distinct regions 1702, 1703, 1704, and 1710 circumferentially spaced apart from each other. In an illustrated embodiment, for example, the shutter body 1701 may include a first reference region 1702, a second reference region 1703, an infrared imaging region 1704, and a visible light imaging region 1710. In some embodiments, the first reference region 1702 and / or the second reference region 1703 may be opaque to infrared radiation. The system 1000 may include an infrared imaging aperture 1709, which may correspond to the front aperture of the system 1000. For example, during operation of the system 1000, infrared radiation from at least an object may pass through the infrared imaging aperture 1709 and reach the optical elements of the system 1000 (e.g., filters, lenses, etc.). The system 1000 may also include a visible light imaging aperture 1711 through which visible light from at least an object passes. The visible light imaging aperture 1711 may be at least transparent to visible light, allowing visible light from an object to pass through the aperture 1711 and reach the visible light imaging system 1680, which may include a visible light sensor to capture visible light image data from the object.

[0294] Processing electronics may be provided in processing unit 1611 to control the operation of drive system 1708. The processing electronics may include one or more processors programmed to instruct a motor to rotate shaft 1705 about its axis of rotation. Rotation of shaft 1705 and shutter body 1701 causes regions 1702, 1703, 1704, and 1710 to also rotate. To calibrate system 1000, drive system 1708 may rotate shutter body 1701 such that first reference region 1702 is substantially aligned with infrared imaging aperture 1709. First reference region 1702 may be at a known or measured first temperature. For example, in some embodiments, first reference region 1702 may be actively maintained at a predetermined temperature by one or more heating or cooling elements. In some embodiments, the first temperature of first reference region 1702 may be monitored by one or more temperature sensors (e.g., thermocouples, etc.) (with or without active heating or cooling). Thus, system 1000 may accurately measure or otherwise store an approximate temperature of first reference region 1702. When the first reference region 1702 is aligned with the infrared imaging aperture 1709, the optical detector can acquire first calibration image data representing the first temperature of the first reference region 1702.

[0295] Similarly, the drive system 1708 can be activated to rotate the shutter body 1701, causing the second reference region 1703 to be substantially aligned with the infrared imaging aperture 1709. Like the first reference region 1702, the second reference region 1703 can be actively maintained at a second predetermined temperature by one or more heating or cooling elements. In some embodiments, the second temperature of the second reference region 1703 can be monitored by one or more temperature sensors (e.g., thermocouples, etc.) (with or without active heating or cooling). Therefore, the system 1000 can accurately measure or otherwise store an approximate temperature of the second reference region 1703. When the second reference region 1703 is aligned with the infrared imaging aperture 1709, the optical detector can acquire second calibration image data representing the second temperature of the first reference region 1703, which may differ from the first temperature of the first reference region 1702 by a known and / or predetermined amount.

[0296] During operation (e.g., when calibration is complete and the user wishes to acquire image data of the object), the drive system 1708 can rotate the shutter body 1701 so that the infrared imaging region 1704 is substantially aligned with the infrared imaging aperture 1709 of the DAISI system 1000. The visible light imaging region 1710 of the shutter body 1701 can be spaced relative to the infrared imaging region 1704 of the shutter body 1701 such that when the infrared imaging region 1704 is aligned with the infrared imaging aperture 1709 of the system 1000, the visible light imaging region 1710 is also aligned with the visible light imaging aperture 1711 of the system 1000. When the infrared imaging region 1704 and the visible light imaging region 1710 are aligned with the corresponding apertures 1709 and 1711, infrared radiation from the object can pass through the infrared imaging region 1704 and the infrared imaging aperture 1709 and reach the infrared imaging optics. Similarly, when the infrared imaging region 1704 and the visible light imaging region 1710 are aligned with the corresponding apertures 1709 and 1711, visible light radiation from the object can pass through the visible light imaging region 1710 and the visible light imaging aperture 1711 and reach the visible light imaging system 1680.

[0297] The shutter body 1701 may include any suitable number of reference areas, and the reference areas may be set at any suitable location on the body 1701. Furthermore, the shutter body 1701 may include embedded processing electronics for controlling the operation of various components such as temperature sensors, drive systems 1708, active heating elements, and / or cooling elements. Advantageously, Figure 17A The implementation scheme enables the DAISI system 1000 disclosed herein to be calibrated effectively by rotating a single rotary shutter wheel.

[0298] C. Dual shutter

[0299] Figure 17B This is a schematic exploded perspective view of shutter 1621A according to some implementation schemes. Figure 17C This is a front view of the shutter 1621A in its closed configuration. Figure 17D This is a front view of the shutter 1621A in its open configuration. The shutter 1621A can be used with any DAISI System 1000 disclosed herein.

[0300] The shutter 1621A may include a drive system 1708, which includes a first drive element 1708A and a second drive element 1708B. The first drive element 1708A and the second drive element 1708B may include a motor configured to impart rotation to the corresponding first shutter body 1701A and second shutter body 1701B. The first drive element 1708A and the second drive element 1708B may be spaced apart from each other in a laterally direction. The first drive element 1708A and the second drive element 1708B may have a drive shaft connected to a corresponding drive gear 1721A, 1721B, each drive gear may have multiple gear teeth. The drive shaft of the motor (not shown) to which gears 1721A, 1721B are connected may be disposed in a corresponding recess 1725 of the frame 1720. Figure 17C and Figure 17D As shown, drive gears 1721A and 1721B can be positioned above shutter bodies 1701A and 1701B. Drive gears 1721A and 1721B can be separated from drive elements 1708A and 1708B via frame 1720.

[0301] Slip rings 1722A and 1722B can be disposed in corresponding holes 1726 of frame 1720. In some embodiments, slip rings 1722A and 1722B can be configured to rotate within holes 1726. Corresponding gear shafts 1727A and 1727B can be mounted to corresponding flanges of slip rings 1722A and 1722B. First shutter body 1701A and second shutter body 1701B can be fixed to corresponding shutter gears 1723A and 1723B. Retaining washers 1724A and 1724B can be provided to secure shutter bodies 1701A and 1701B and gears 1723A and 1723B to gear shafts 1727A and 1727B.

[0302] like Figure 17C and Figure 17D As shown, drive gears 1721A and 1721B can be operatively engaged with shutter gears 1723A and 1723B. To rotate shutter bodies 1701A and 1701B, drive elements 1708A and 1708B can be activated to rotate drive gears 1721A and 1721B, which in turn causes shutter gears 1723A and 1723B to rotate. For example, the gear teeth of drive gears 1721A and 1721B can mesh or interlock with corresponding gear teeth of shutter gears 1723A and 1723B. Rotation of shutter gears 1723A and 1723B causes shutter bodies 1701A and 1701B to rotate about corresponding axes parallel to the optical axis of the DAISI system 1000. For example, in some arrangements, rotation of shutter bodies 1701A and 1701B can cause slip rings 1722A and 1722B to rotate within hole 1726.

[0303] as Figure 17A The implementation plan, in Figures 17B to 17D In some embodiments, shutter 1621A can be used to calibrate DAISI system 1000. For example, the first shutter body 1701A can be at a known or measured first temperature. For example, in some embodiments, the first shutter body 1701A can be actively maintained at a predetermined temperature by one or more heating or cooling elements. In some embodiments, the first temperature of the first shutter body 1701A can be monitored by one or more temperature sensors (e.g., thermocouples, etc.) (with or without active heating or cooling). Thus, system 1000 can accurately measure or otherwise store an approximate temperature of the first shutter body 1701A. When the first shutter body 1701A is aligned with infrared imaging aperture 1709, an optical detector can acquire first calibration image data representing the first temperature of the first shutter body 1701A.

[0304] Similarly, the second shutter body 1701B can be at a known or measured second temperature. For example, in some embodiments, the second shutter body 1701B can be actively maintained at a predetermined temperature by one or more heating or cooling elements. In some embodiments, the second temperature of the second shutter body 1701B can be monitored by one or more temperature sensors (e.g., thermocouples, etc.) (with or without active heating or cooling). Thus, system 1000 can accurately measure or otherwise store an approximate temperature of the second shutter body 1701B. When the second shutter body 1701B is aligned with the infrared imaging aperture 1709, the optical detector can acquire second calibration image data representing the second temperature of the second shutter body 1701B.

[0305] exist Figure 17C In the diagram, shutter 1621A is shown in a closed configuration, with one or more shutter bodies 1701A and 1701B aligned with the infrared imaging aperture 1709. In the closed configuration, shutter body 1701A can be positioned in a lateral region between two axes of rotation along the lateral direction. In the illustrated arrangement, both shutter bodies 1701A and 1701B are aligned with aperture 1709. In other arrangements, drive system 1708 can independently align each of shutter bodies 1701A and 1701B with aperture 1709. For example, system 1000 can rotate the first shutter body 1701A to align with aperture 1709, thereby acquiring a first calibration measurement result, such as... Figure 17DAs shown. Simultaneously, the system 1000 can rotate the second shutter body 1701B to its closed position (i.e., aligned with aperture 1709), or it can rotate the second shutter body 1701B to its open position. To acquire the second calibration measurement result, the system 1000 can rotate the first shutter body 1701A to expose aperture 1709, and can rotate the second shutter body 1701B to align with aperture 1709. In its closed configuration, the shutter body 1701B can be positioned in the lateral region between the two rotation axes along the lateral direction. When calibration is complete, the drive system 1708 can rotate both shutter bodies 1701A and 1701B to their respective open positions to expose the infrared imaging aperture 1709, as shown. Figure 17D As shown. As explained above, infrared radiation from an object (such as a cloud of gas) can enter aperture 1709 and illuminate imaging optics such as filter 1620, lens, etc.

[0306] D. Lens array

[0307] The aperture-splitting infrared spectroscopy imaging (DAISI) system described herein (including the DAISI system disclosed in Part II above and the mobile DAISI system disclosed in Part III above) may include features such as lens arrays formed with a monolithic lens substrate, lens arrays formed with separate lens substrates, patterned optical filters, separate optical filter arrays, and cooling modules coupled to components such as optical focal plane array (FPA) units and lens assemblies.

[0308] As described herein, the DAISI system may include a lens assembly 1502, which includes a lens array 1002. (In conjunction with...) Figure 18A As disclosed, each lens in the lens array 1002 may at least partially define or be included in the optical channel to be imaged by the FPA unit 1008.

[0309] In at least some embodiments, a baffle 2500 may be provided (e.g., in mounting plate 1584) to reduce or block stray light. The baffle 2500 may reduce or block light entering via one optical channel (which may be associated with a lens) from exiting the lens assembly 1502 via another optical channel (which may be associated with another lens). The baffle 2500 may be formed of any desired material and using any desired technique. As an example, the baffle 2500 may comprise a sheet of metal having lens openings formed by mechanical or laser cutting. If desired, the baffle 2500 may be formed of a material with a coefficient of thermal expansion (CTE) similar to or matching that of the substrate 2501. By having a similar or matching CTE, the baffle 2500 and the substrate 2501 can maintain optical performance over a wide temperature range.

[0310] 1. Monolithic substrate for lenses

[0311] like Figure 18A and Figure 18B As shown, the lens array 1002 can be formed from one or more monolithic substrates 2501. In other words, multiple lenses in the lens array 1002 (i.e., some or all of the lenses) can share a single common substrate. The monolithic substrate can be formed in a manner that provides lenses associated with multiple optical channels. Figure 18B As shown, all lenses of the lens array 1002 can be formed from a single monolithic substrate 2501. In this way, the monolithic lens substrate 2501 can include a portion of a lens corresponding to each optical channel in the DAISI system. For example, the monolithic substrate 2501 can include a lens portion 2502A corresponding to the first optical channel, a lens portion 2502B corresponding to the second optical channel, and so on.

[0312] Although Figure 18B A monolithic lens substrate 2501 is shown having multiple lens portions formed by corresponding shaped (e.g., spherical) portions of the substrate. However, the monolithic lens substrate 2501 can also be an optical substrate based on a gradient index (i.e., the lens substrate 2501 can form a GRIN lens). In such an arrangement, the monolithic substrate 2501 can be formed to have a flat surface, but with a variation in the refractive index of the substrate material forming the lens, focusing light through each lens portion 2502A, 2502B, etc., in the same manner as conventionally shaped lenses. The lens substrate (such as the monolithic substrate 2501) can also be formed by a combination of lens-forming shaped portions and lens-forming variations in the refractive index of the substrate material.

[0313] Lens substrate 2501 can be formed from any suitable material, including but not limited to silicon, germanium, chalcogenide glass, calcium fluoride, zinc selenide, zinc sulfide, gallium arsenide, cadmium telluride, and BLACK DIAMOND-2. TM (Chalcogenides made from an amorphous mixture of germanium, antimony, and selenium), AMTIR TM (Amorphous materials that transmit infrared radiation), thallium bromide, IR fused silica, sodium chloride, potassium bromide, potassium chloride, sapphire, quartz crystal, UV fused silica, barium fluoride, calcium fluoride, magnesium fluoride, lithium fluoride, etc. The lens substrate 2501 can preferably be formed of a material transparent to the infrared wavelength and / or other wavelengths to which the system 1000 is configured for detection, and can be formed of glass, crystalline materials, and / or other suitable materials.

[0314] The lens substrate 2501 can be molded into a desired shape (i.e., individual lens portions 2502A, 2502B, etc., can be formed by molding processes). Molding processes may be particularly suitable when the lens substrate 2501 is formed of glass or other amorphous materials. The lens substrate 2501 can also be ground or cut into a desired shape (i.e., individual lens portions 2502A, 2502B, etc., can be formed by diamond cutting or other methods). Grinding and cutting processes may be particularly suitable when the lens substrate 2501 is formed of crystalline or other similar materials. Generally, combinations of molding, grinding, cutting, and other similar processes can be used to shape the lens substrate 2501, regardless of whether the lens substrate 2501 is formed of amorphous, crystalline, or other materials.

[0315] 2. Separate lens substrate

[0316] like Figure 18C as well as Figures 18D to 18E As shown, the lens array 1002 can be formed from an array of individual lens substrates (also referred to herein as individual lenses), such as lens substrates 2504A, 2504B, etc. By forming the lens array 1002 from an array of individual lenses, the manufacturing of the lens array 1002 can be simplified (i.e., in at least some scenarios, producing multiple individual lenses can be simpler compared to a monolithic substrate comprising multiple lens portions). The individual lenses 2504A, 2504B, etc. in the lens array 1002 can be formed from any suitable material, including those described herein in conjunction with the monolithic lens substrate 2501. The individual lenses 2504A, 2504B, etc. in the lens array 1002 can be formed using any suitable technique, including those described herein in conjunction with the monolithic lens substrate 2501.

[0317] Whether formed from a single lens substrate or a monolithic lens substrate, the lens array 1002 can be mounted in the lens holder 1584 (also referred to herein as a mounting plate). The lens holder 1584 can be formed from any desired material and using any desired technique. As an example, the lens holder 1584 can be formed of metal with lens openings formed by mechanical or laser cutting. In at least some embodiments, the lens holder 1584 can be formed of a material with a coefficient of thermal expansion (CTE) similar to or matching the CTE of the lenses in the lens array 1002. With a similar or matching CTE, the lens holder 1584 and the lenses in the lens array 1002 can maintain optical performance over a wide temperature range. In other words, with a similar or matching CTE, the lens holder is able to maintain the optical alignment of lens portions 2502A, 2502B, etc., or individual lenses 2504A, 2504B, etc., even if the temperature of the entire system changes. As a specific example, the lens holder 1584 can be formed from... (A nickel-cobalt-iron alloy with CTE properties that are essentially similar to those of germanium) is formed. It can have approximately 5.5 × 10 -6 The CTE is approximately 3 × 10⁻⁶ K (at temperatures below 200°C), while borosilicate glass can have a CTE of approximately 3 × 10⁻⁶ K. -6 / degree K up to 6×10 -6 CTE at / degrees K (at temperatures below 200°C).

[0318] Figure 18D It shows Figure 18C An exploded perspective view of the imaging system. Figure 18E It shows Figure 18C A cross-sectional view of the imaging system. For example... Figure 18D and Figure 18E As shown, the lens array 1002 may include multiple optical layers, such as front lenses 2504A, 2504B, etc.; intermediate lenses 2506A, 2506B, etc.; and rear lenses 2508a, 2508B, etc. Additionally, the lens array 1002 may include gaskets or other mounting structures 2514 and 2516 that hold the front, intermediate, and rear lenses together when the lens array 1002 is assembled with the lens holder 1584. Furthermore, the imaging system may include a filter housing 2510 comprising an array of filters 2512A, 2512B, each filter corresponding to a specific optical channel and a corresponding group of front, intermediate, and rear lenses. In at least some embodiments, the front, intermediate, and rear lenses may be recessed into the front portion of the lens holder 1584 and secured by the filter housing 2510. Figure 18D The arrangement can reduce the possibility of stray light (i.e., light that enters the first optical channel and is flipped across to the second optical channel). In other words, when the lens is recessed into the lens holder 1584, the lens holder 1584 can operate as a stray light blocking baffle.

[0319] Figure 18D The intermediate lens 2506 and rear lens 2508 shown herein can be formed using materials similar to those described herein in conjunction with lens 2504. Additionally, the intermediate lens 2506 and rear lens 2508 can be formed using manufacturing techniques similar to those described herein in conjunction with lens 2504. In at least some embodiments, the intermediate lens 2506 may have relatively flat front and rear surfaces, while the front lens 2504 and rear lens 2508 have curved front and rear surfaces. In at least some other embodiments, some or all of the front, intermediate, and rear lenses are formed from GRIN lenses.

[0320] E. Filter array

[0321] As discussed herein, gas and chemical imaging systems may include an array 2550 of optical filters, such as Figure 19 The array 2550 shown defines different sub-images in the spectrum. These optical filters can each pass through different wavelengths, wavelength ranges, bands, or sets of wavelengths or wavelength ranges or bands of incident light. In at least some embodiments, some or all of the optical filters include filters that allow different wavelengths or sets of wavelengths of incident light in the infrared range (e.g., typically extending from about 1 micrometer to about 20 micrometers) to pass through. Figure 6A , Figure 6B , Figure 6C and Figure 6D Theoretical graphs illustrating the transmission characteristics of optical filters that can be used in gas and chemical imaging systems of the type described herein are presented and described. Figure 6A , Figure 6B , Figure 6C and Figure 6D The optical filters shown and described are merely illustrative.

[0322] Although the filter and filter array 2550 are generally described herein as separate from the optical lens array 1002 (and lenses 2502, 2504, 2506, or 2508), the filter may be incorporated into or on some or all of the lenses of the optical lens array 1002 if desired. In particular, the filter array 2550 may be disposed as a coating on some or all of the lenses of the lens array 1002. In an arrangement where the lens array 1002 is formed from a monolithic substrate, the filter array 2550 may be formed from a patterned filter array (as described herein) coated on or integrated within the monolithic substrate. In an arrangement where the lens array 1002 is formed from individual lenses, the filter array 2550 may be formed from individual filters coated on or integrated into some or all of the individual lenses.

[0323] 1. Patterned filter array

[0324] like Figure 19 As shown, a filter array 2550 can be provided, which includes patterned elements to form individual optical filters 2512A, 2512B, etc. (in...) Figure 19The substrate 2501 (also labeled 1, 2, ..., 12) is provided with infrared blocking material 2558 between the individual filters. Filter array 2550 may also be referred to herein as filter array 454. Each individual optical filter 2512A, 2512B, etc., can only transmit the infrared radiation required by its respective optical channel and its respective infrared detector. In at least some embodiments, the individual optical filters selectively transmit at least one wavelength or wavelength range or band or set of wavelengths or wavelength ranges or bands in the infrared range of approximately 1 micrometer to 20 micrometers, in the infrared range of approximately 7 micrometers to 14 micrometers, or in the infrared range of approximately 3 micrometers to 14 micrometers or 3 micrometers to 8.5 micrometers. As an example, one or more spectral channels in system 1000 may have infrared filters (which may be formed by multiple filters) that transmit infrared light in both the 3 micrometer to 4 micrometer range and the 6 micrometer to 8 micrometer range (or the 7 micrometer to 8.5 micrometer range, or the 7 micrometer to 8 micrometer range, or other suitable ranges). In other words, system 1000 may include a dual-notch infrared filter in at least one spectral channel. This dual-notch filter is particularly useful for detecting the infrared signature of specific gases, such as methane, even without information from other spectral channels in system 1000. Notch filters typically attenuate wavelengths that fall outside their pass range. As an example, a dual-notch filter passing infrared light in both the 3-4 μm and 6-8.5 μm ranges can attenuate wavelengths shorter than 3 μm, wavelengths between 4 and 6 μm, and wavelengths longer than 8.5 μm. Infrared blocking material 2258 can help reduce optical crosstalk, or stray light that enters the first optical channel but undesirably flips across to the second optical channel.

[0325] Individual optical filters 2512A, 2512B, etc., can be formed on substrate 2501 using any suitable technique or combination of techniques. For example, the optical transmission characteristics of individual optical filters can be tuned by changing the type of one or more materials deposited at each optical filter location, the thickness of one or more materials formed at each optical filter location, the number of layers of one or more materials at each optical filter location, etc. In at least some embodiments, the optical filters can be interference filters, and can be bandpass, high-pass, low-pass, or bandstop filters. In at least some embodiments, the optical filters can be formed from one or more thin film layers that determine the optical transmission characteristics of the filter. Interference coatings with different designs (e.g., different numbers or arrangements of layers, different materials, different thicknesses of layers, etc.) can be used. Forming individual optical filters 2512A, 2512B, etc., may involve processing steps such as masking, etching, deposition, planarization, doping, and stripping of mask materials. In this way, one or more optical filters can be selectively processed while protecting one or more other optical filters.

[0326] Infrared blocking material 2558 can be used as a baffle, aperture stop, or field stop, and can be patterned onto substrate 2501 in the space between filters 2512. Infrared blocking material 2558 can be formed of any suitable material, such as chromium, that blocks light, including stray light between filters 2512. In at least some embodiments, infrared blocking material 2558 can be formed to implement apodization (i.e., a smoothly varying transmission distribution, a smoothly varying transmission distribution as a function of position in the filter array, etc.). In particular, infrared blocking material 2558 can provide a slowly varying gradient baffle, aperture stop, or field stop, having maximum transmittance near the center of the filter, minimum or zero transmittance in the space between filters, and some intermediate transmittance near the edges of the filters. Infrared blocking material 2258 can be formed in this way using suitable patterning and processing techniques.

[0327] 2. Individual or Diced Filters

[0328] Figures 20A to 20CAn alternative arrangement of filter array 2550 is shown, wherein filter array 2550 is formed from individual filters. In this arrangement, batches of filters are produced using suitable processing steps (as described in conjunction with patterned filters herein). Each batch may include multiple copies of a particular filter (i.e., one of filters 2512A, 2512B, etc.). After batch formation, the multiple copies of that particular filter may be separated or diced to produce individual copies of that particular filter. The individual copies of each filter in filter array 2550 that have been separated or diced from their respective batches may then be assembled into filter array 2550. With this type of arrangement, processing each batch can be slightly simplified because each substrate being processed includes only a single type of filter. The benefits of simplified batch processing may outweigh any additional complexity involved in separating or dicing and subsequently assembling the individual filters into filter array 2550.

[0329] like Figure 20B and Figure 20C As shown in the rear view, the filter housing 2510 may include alignment structures 2560A, 2560B, etc., in which individual filters 2512A, 2512B, etc., are mounted and aligned. Alignment structures 2560A, 2560B may be formed by recesses, registration features, posts, other suitable elements, or combinations of these and other elements in the filter housing 2510. In at least some embodiments, individual filters can be pressure-secured to the housing 2510 when assembled to the mounting plate 1584. If desired, individual filters may also be secured to the housing 2510 by pressure (i.e., by snapping into appropriate positions in recesses of the housing 2510), adhesive, screws, clamps, or other fastening elements.

[0330] F. Detector array

[0331] As discussed herein, gas and chemical imaging systems may include detectors such as an optical focal plane array (FPA) 1508. The FPA 1508 can receive light from multiple optical channels that are spatially separated, and the light may be spectrally different, for example, by means of a filter array 2550. In at least some embodiments, the FPA 1508 may be formed by one or more arrays of microbolometers configured to detect infrared radiation, as discussed in more detail herein. In at least some embodiments, individual lenses 2502, 2504, etc., and filters 2512 may be laterally spaced within a range of approximately 2 mm to approximately 20 mm, approximately 3 m to approximately 10 mm, approximately 4 mm to approximately 8 mm, approximately 4.3 mm, or some other suitable distance. Similarly, the spatially and spectrally spaced channels of the FPA 1508 may be physically spaced between approximately 2 mm to 20 mm, 3 mm to 10 mm, 4 mm to 8 mm, approximately 4.3 mm, etc.

[0332] Figure 21 The imaging system is also shown to include components such as FPGA board 2590, signal conditioning board 2592, and data communication board 2594. FPGA board 2590 and signal conditioning board 2592 can be configured to perform methods used in analyzing images captured by the optical system, as discussed herein (see, for example, [reference to...]). Figure 12 (See discussion of processing unit 1021). Data communication board 2594 can be configured to communicate with at least one device physically separated from the imaging system (e.g., via a wired or wireless connection), as discussed herein (see example...). Figure 12 (Discussion of communication module 1024).

[0333] 1.TEC cooling

[0334] like Figure 21As shown, the FPA 1508 can be actively cooled, heated, temperature-stabilized, and / or actively thermally controlled using a thermoelectric cooling (TEC) device 2570 utilizing the Peltier effect (which can also operate as a heater) or using another cooling and / or heating device. The TEC device 2570 can be coupled to a heat sink 2572 and a heat sink fan 2574. In operation, the TEC device 2570 can transfer heat from the FPA 1508 to the heat sink 2572, and the heat sink fan 2574 can transfer heat to the surrounding environment. If needed, the heat sink 2572 can be cooled by liquid cooling in addition to or instead of the heat sink fan 2574. The imaging system may include a temperature sensor thermally coupled to the FPA 1508 or the TEC device 2570. The temperature sensor may be integrated into the FPA 1508, integrated into the TEC device 2570, or may be a separate device. The TEC device 2570 can be configured to monitor the temperature of the FPA 1508 using a temperature sensor and, in response, maintain the FPA 1508 at a target temperature. By maintaining a relatively constant temperature for the FPA 1508, the calibration of the FPA 1508 can be improved or optimized. Specifically, after the TEC device 2570 cools the FPA 1508 to a desired operating temperature, the FPA 1508 can be calibrated, and then the TEC device 2570 can maintain the FPA 1508 at that operating temperature to maintain the calibration. The TEC device 2570 can optionally operate at maximum or other preset cooling power to maintain the FPA 1508 at the lowest possible temperature. The TEC 2570 can optionally maintain the temperature of the FPA 1508 within a desired range, such as below a first temperature, above a second temperature, etc. In some embodiments, the TEC 2570 can cryogenically cool the FPA 1508. In other implementations, the TEC 2570 can cool the FPA 1508 to non-cryogenic temperatures, such as ambient temperature, 10°C, 20°C, or 30°C below ambient temperature, or temperatures independent of the environment, such as -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, and any range within any combination of these temperatures. The TEC device 2570 can be a single-stage TEC cooler or can include multiple stages (e.g., a first TEC stage has a "hot side" cooled by a larger second TEC stage, which itself has a hot side cooled by a radiator). The temperature (absolute temperature or relative to ambient temperature) to which the TEC unit 2570 cools the FPA 1508 can be pre-configured, can be set by the user, or can be determined as part of a calibration process.As an example, the calibration process may include determining that the FPA 1508 needs to be cooled to a certain temperature (either absolute or relative to ambient temperature) to achieve the desired performance level. In response, the cooling controller in the imaging system can configure itself based on the calibration results to maintain the FPA 1508 at that temperature. In this way, the accuracy of gas and chemical detection by the FPA 1508 can be improved.

[0335] The imaging system may include one or more controllers that control the operation of cooling units such as TEC units 2570 and 2580. The controllers may receive input from thermometers (i.e., temperature sensors) coupled to the element being cooled, thermometers determining the ambient temperature, other processors and controllers in the imaging system, feedback from the TEC units or other cooling units, etc. The controllers may adjust the operation of the TEC units in real time to maintain cooling performance and the desired temperature of the element being cooled.

[0336] 2. TEC cooling for optical devices

[0337] If desired, the lens assembly 1502, including elements such as the lens array 1002, mounting plate 1584, and filter housing 2510, can be actively cooled and / or heated using a thermoelectric cooling (TEC) device 2580 utilizing the Peltier effect or using another cooling and / or heating device. The TEC device 2580 can be coupled to a heat sink 2582 and a heat sink fan 2584. In operation, the TEC device 2580 can transfer heat from the lens assembly 1502 to the heat sink 2582, and the heat sink fan 2584 can transfer heat to the surrounding environment. If desired, the heat sink 2582 can be cooled by liquid cooling in addition to or instead of the heat sink fan 2584. The TEC device 2580 can be provided with any features and can operate using any of the techniques discussed herein in conjunction with the TEC device 2570. As an example, the TEC device 2580 can actively cool the lens assembly 1502 to a cryogenic or non-cryogenic temperature. The temperature of the lens assembly 1502 can be monitored using a thermometer. It can be a single-stage or multi-stage TEC device, facilitating calibration and maintenance of calibration performance. Actively cooling the lens assembly 1502 improves the accuracy of gas and chemical detection by the FPA 1508.

[0338] As schematically shown with thermal connector 2586, lens assembly 1502 can optionally be actively cooled by TEC device 2570. Thermal connector 2586 can be heat pipe 2582 or other devices. In other words, TEC device 2570 can provide primary cooling to FPA 1508 and secondary cooling to lens assembly 1502 via heat pipe 2586, by mounting lens assembly 1502 to FPA 1508 and / or TEC device 2570, or via other devices.

[0339] G. Reduce crosstalk

[0340] DAISI systems (whether fixed or mobile) can include lens arrays for imaging objects (such as gas clouds) using optical detectors. For example, as described herein... Figures 18A to 18E The DAISI system may include a lens assembly 1502 comprising lens arrays 2504, 2506, and 2508 that at least partially define or include in the optical channels to be imaged by the FPA unit 1008. In some embodiments described throughout this application, the DAISI system is configured as an infrared (IR) imaging system for imaging an object. FPAs configured to image IR radiation can be expensive, and therefore, positioning the optical channels close together or as close as possible physically may be advantageous to increase or maximize the usable area of ​​the FPA unit 1008. However, positioning the optical channels close together can cause unwanted stray light from one optical channel to flip across to adjacent optical channels, also referred to herein as "optical crosstalk." In various embodiments, the lenses may be edge-to-edge spaced apart by distances ranging from 0 mm to 2 mm, 0 mm to 1 mm, 0 mm to 0.5 mm, or 0.05 mm to 0.5 mm, for example, approximately 0.1 mm.

[0341] For example, Figure 22A It is shown Figure 18D A ray trajectory diagram illustrating an example of optical crosstalk between the optical channels of lens assembly 1502. Unless otherwise stated, Figure 22A The same reference numerals in the figures indicate the same as Figures 18A to 18E Components with the same number are identical or similar components. Figure 22A Combining Figures 18A to 18E The various optical elements described are illustrated as a collection of optical surfaces (in...) Figure 22A (Represented as a plane). For example, lens assembly 1502 may include lens 2504, lens 2506, lens 2508, filter 2512, and optical window 2607. Figure 22AThe front and rear surfaces of each of lenses 2504, 2506, and 2508, as well as the optical window 2607, are schematically shown. Lens assembly 1502 can be used to image an object 2601 spaced apart from lens assembly 1502 along axis 2680 of optical detector 2610. Figure 22A Lenses 2504A, 2506A, and 2508A corresponding to the optical channel 2602A arranged along axis 2680A are depicted. Although Figure 22A Nine different optical channels 2602 are depicted, but any number (two, three, four, five, six, seven, eight, nine, twelve or more) of optical channels 2602 is possible.

[0342] Each optical channel 2602 is configured to collect light from object 2601 and transmit the light (denoted as ray 2605) along its corresponding axis 2680 to optical detector 2610. Optical detector 2610 can generate data representing an image corresponding to the light received by each optical channel 2602. However, as... Figure 22A As shown, due to the angle of incidence of light on the optical surface and the refractive properties of the lens, some light may cross between adjacent optical channels. For example, light rays 2605A and 2605B are refracted by lens 2504 into adjacent optical channels and leave the desired optical channel 2605 (in Figure 22A In the case of a central optical channel, a portion of the light incident on one optical channel can cross into an adjacent optical channel (e.g., optical channel 2602A) and be added to the light from the object 2601 as it is transmitted from the adjacent optical channel to the optical detector 2610. The additional light from the adjacent optical channel may distort, damage, or otherwise interfere with the data corresponding to a given optical channel 2602.

[0343] Therefore, in DAISI systems comprising lens arrays with densely packed optical channels, controlling stray light is crucial. The various embodiments disclosed herein employ various techniques that can provide such control to increase, improve, or optimize the illumination of the optical detector while reducing the impact of stray light on the resulting image. For example, a DAISI system can be configured to provide vignetting of the image of the optical channels at the optical detector to eliminate or at least partially reduce optical crosstalk between optical channels. Vignetting in a DAISI system can be caused by at least a partial reduction in the brightness or illuminance of light at the periphery or edge of the optical channels. For example, a DAISI system may include one or more baffles or aperture elements configured to at least partially block stray light from crossing between optical channels while allowing light incident on the optical channels to pass through. These baffles or aperture elements can also be configured to at least partially block stray light that has already crossed between optical channels from reaching the optical detector. In densely packed lens array systems, reducing optical crosstalk between optical channels can be important because as optical channels are placed more closely together, optical crosstalk between them can increase, thereby reducing the quality of the acquired data.

[0344] In various embodiments, each of the systems disclosed herein can be used to monitor potential gas leaks at any suitable installation site, including but not limited to drilling rigs, refineries, pipelines, transportation systems, ships, or other vessels (such as offshore oil rigs, trains, tanker trucks, petrochemical plants, chemical plants, etc.). Furthermore, each of the systems disclosed herein can also be used with any mobile DAISI system, including but not limited to systems worn or carried by a user. Additionally, this document, for example, relates to… Figures 22A to 22G Each disclosed and illustrated embodiment and aspect may be used in combination with any or any combination of the features disclosed and illustrated in this application.

[0345] Figure 22B This is an exploded perspective view of a lens assembly 2702 configured to at least partially reduce optical crosstalk, which can be used in conjunction with a DAISI system. Lens assembly 2702 is substantially similar to... Figures 18A to 18E Lens assembly 1502. Unless otherwise specified, Figure 22B The same reference numerals in the figures indicate the same as Figures 18A to 18E Components with the same number are identical or similar components. Although lens assembly 2702 is described in conjunction with lens assembly 1502, the various features described herein can be used in conjunction with any other suitable type of optical system. For example, in conjunction with Figures 18A to 18E Described Figure 22BVarious lenses and lens arrays, as well as components, are shown. However, lens assembly 2702 may include any number or combination of lenses and optical elements that may correspond to multiple spatially and spectrally different optical channels as described herein.

[0346] Lens assembly 2702 can be designed to block stray light that has traveled between one optical channel and another. In some embodiments, lens assembly 2702 can also be configured to allow light incident on a given optical channel to be transmitted by that optical channel to a corresponding area of ​​the optical detector (e.g., as combined below). Figure 22D (The detection area is mentioned above). In various embodiments, the optical detector may include a single focal plane array. In various other embodiments, the optical detector may include multiple focal plane arrays. For example, lens assembly 2702 may include at least one baffle 2630 configured to control stray light to provide at least partial vignetting of the image at the optical detector. In some embodiments, lens assembly 2702 may include two baffles 2620 and 2630. Unless otherwise stated, baffles 2620 and 2630 may be substantially similar to Figures 18A to 18E Baffle 2500 is configured to at least partially block light from crossing between optical channels. Baffles 2620 and 2630 may be configured to at least partially block stray light passing through adjacent optical channels from being transmitted to the optical detector. In various embodiments, the baffles are configured to substantially cause vignetting of the image at or a portion of the optical detector array.

[0347] For example, baffle 2620 can be configured to reduce or at least partially block light entering through one optical channel from exiting through another optical channel from the lens assembly 2702. In some embodiments, baffle 2620 is configured to significantly reduce light crossing between optical channels. Baffle 2620 can be positioned in front of optical channel 2602. In some embodiments, baffle 2620 can be disposed near lens 2504 and / or between lens 2504 and object. Figure 22B (Not shown in the image). In another embodiment, alternatively or in combination, baffle 2620 may be disposed between filter housing 2510 and the object. In some embodiments, baffle 2620 may be formed as part of filter housing 2510, or integrated into a recess in filter housing 2510 (e.g., ...). Figure 18D (As shown). In one embodiment, the baffle 2620 is positioned as close as possible to the filter housing 2510 within manufacturing tolerances.

[0348] Such as combination Figures 18A to 18EThe baffle 2620 may include a light-attenuating or light-blocking surface, such as a sheet or plate comprising a light-attenuating or light-blocking material (e.g., metal or plastic), the light-attenuating or light-blocking surface having a plurality of openings 2622 (e.g., also referred to as apertures) formed, for example, by mechanical or laser cutting. Each opening 2622a, 2622b, etc., may be along the axis of a corresponding optical channel (e.g., Figure 22A The axis 2680 is provided. The opening 2622 can be configured to control the light incident on the optical channel by modifying the light path entering the optical channel. For example, each opening 2622 can be configured to block stray light that would otherwise be incident on the outer edge of the corresponding optical channel. The opening 2622 can also be configured to allow light incident on the central region of the optical channel to be transmitted to the optical detector via the optical channel onto which the light is incident. Figure 22B (Not shown in the image). Therefore, the light is at least partially or substantially blocked, so that stray light does not cross into the adjacent optical channel.

[0349] Despite multiple openings 2622 Figure 22B The opening 2622 is shown as having a circular shape, but it should be understood that the opening 2622 can have any suitable shape (e.g., oval, rectangular, square, etc.) to cause vignetting of the image at the optical detector. The shape, size, and position of the opening 2622 can be based on the optical characteristics and arrangement of the elements in the lens assembly 2702. For example, the lens assembly 2702 may include an optical stop layer 2650, which includes a plurality of optical stops 2655a, 2655b, etc., corresponding to each optical channel. In one embodiment, the optical stop layer 2650 may be disposed between lenses 2504 and 2506. The size of the plurality of openings 2622 may be based at least in part on the position of the optical stop layer 2650 within the lens assembly 2702. For example, for Figure 22B In the illustrated embodiments, each opening 2622 has a lateral dimension (e.g., diameter, side length, etc.) in the range of 3 mm to 6 mm, or 4 mm to 5 mm, for example, about 4.4 mm, with a tolerance of about + / - 0.010. The thickness of the baffle can be in the range of 0.05 mm to 0.5 mm, or in the range of 0.1 mm to 0.3 mm, for example, about 0.2 mm. Although the openings 2622 are described herein as each having the same dimensions, it should be understood that this is not intended to be limiting, and each opening 2622 can have different dimensions and / or shapes. In some embodiments, the structure and position of the baffle 2620 can be based on an optical system already optimized for any suitable application.

[0350] In some embodiments, a baffle 2630 is provided, which may be similar to baffle 2620 and is also configured to provide at least a partial vignetting of the image of the object. Baffle 2630 may be positioned at the rear of the optical path, closer to the optical detector array than to the front elements of the lens assembly. In some embodiments, baffle 2630 may be positioned adjacent to lens 2508 and between lens 2508 and the optical detector. In another embodiment, alternatively or in combination, baffle 2630 may be positioned... Figure 18D Between lens 2508 and lens holder 1584. In some embodiments, baffle 2630 may be formed as part of or attached to lens holder 1584. In one embodiment, within manufacturing tolerances, baffle 2630 is positioned as close as possible to the optical detector.

[0351] Similar to baffle 2620, baffle 2630 may include a light-attenuating or light-blocking surface, such as a metal or plastic sheet or plate, having a plurality of openings 2632 formed, for example, by mechanical or laser cutting. Each opening 2632a, 2632b, etc. (e.g., also referred to as a field stop) may be positioned along the axis of the optical channel of lens assembly 2702. The openings 2632 may be configured to control the light transmitted through the optical channel by modifying the light path to the optical channel. For example, each opening 2632 may be configured to block stray light that has already crossed between optical channels, so that such stray light is not transmitted to the optical detector. The openings 2632 may also be configured to allow light incident on a given optical channel to be transmitted by the given optical channel to reach the associated optical detector. For example, baffle 2630 may not affect light incident in the central region of a given optical channel and / or have an angle of incidence that allows light to be transmitted through the given optical channel. Thus, the light is blocked so that it does not interfere with the image formed by adjacent optical channels.

[0352] Despite multiple openings 2632 Figure 22B The opening 2632 is shown as having a rectangular shape, but it should be understood that the opening 2632 can have any suitable shape (e.g., oval, circular, square, etc.) to cause vignetting of the image at the optical detector. As described above in conjunction with baffle 2620, the shape, size, and position of the opening 2632 can be based on the optical characteristics and arrangement of the optical elements in lens assembly 2702. Therefore, the dimensions of the plurality of openings 2632 can be at least partially based on the position and size of optical stop layer 2650. For example, for Figure 22BIn the illustrated embodiments, each opening 2632 has a lateral dimension (e.g., diameter, side length, etc.) ranging from 1 mm to 5 mm, 2 mm to 5 mm, or 3 mm to 4 mm, for example, about 3.2 mm. In various arrangements, the opening 2632 can be polygonal (e.g., square or rectangular) or circular (e.g., elliptical or circular). Although the openings 2632 are described herein as each having the same dimensions, this is not intended to be limiting, and each opening 2632 can have different dimensions and / or shapes. In some embodiments, the baffle 2630 can be configured for any suitable application-designed or optimized optical system and has a component design based on the optical system.

[0353] Lens assembly 2702 can be used in conjunction with an optical system comprising any suitable optical arrangement, such as one or more lenses (e.g., multiple lenses) and / or one or more filters (e.g., multiple filters) for transmitting light to an optical detector. Lens assembly 2702 is one embodiment of a design described in conjunction with various DAISI systems, which may vary in design characteristics (e.g., the DAISI system may be movable or fixed). However, the optical components and their positions within lens assembly 2702 can be modified as needed for any suitable type of imaging application. For example, lens assembly 2702 can be used with any suitable type of infrared imaging system or camera to control stray light to maintain the system's optical performance. Based on the desired application, lens assembly 2702 can be optimized for any specific application with any combination or arrangement of elements. Therefore, the various optical elements of lens assembly 2702 can be modified, moved, removed, etc., for any suitable application. For example, the position of optical stop 2650 can be changed, or the optical power and / or position of lenses 2504, 2506, and / or 2508 can be modified, for example, for a specific application.

[0354] In some implementations, for a given application, controlling stray light and increasing the sensitivity of lens assembly 2702 can be inversely related (e.g., blocking a beam can conversely affect the total amount of light received at the optical detector). Therefore, in some implementations, it may be advantageous to design lens assembly 2702 such that the baffle is configured to block light at the edges of the image or reduce it to approximately 0.1% of the incident light amount at the optical detector at the center of the image (e.g., as described below). Figure 22F and Figure 22G (As described). In another embodiment, alternatively or in combination, it may be advantageous to configure the lens assembly 2702 such that at least about 50% or at least about 60% of the light from the object is delivered to the optical detector (e.g., in combination as follows). Figure 22GAlthough lens assembly 2702 is described as including two baffles 2620 and 2630, it should be understood that lens assembly 2702 may include any number of baffles adapted to cause vignetting of the image at the optical detector for a suitable application.

[0355] Figure 22C This is a forward schematic diagram of optical detector 2610, depicting another example of optical crosstalk between adjacent optical channels, and the potential non-uniformity of the available image size due to crosstalk. Detector 2610 may include a plurality of illumination regions 2616, each of which may correspond to an optical channel 2602 and associated components (such as lenses or lens elements 2504, 2506, 2508). For example, each illumination region 2616 may represent the area of ​​detector 2610 where light entering the first element of the associated optical channel 2602 is incident. In some embodiments, the width of the optical channel 2602 at different locations (e.g., lenses) may be smaller than the corresponding width of the illumination region 2616. Figure 22C In the arrangement shown, optical channels 2602 (including lenses, for example, a lens array) can be spaced apart at approximately uniform intervals in a two-dimensional array. For example, the spacing between adjacent optical channels in the vertical direction can be approximately uniform, and the spacing between adjacent optical channels in the horizontal direction can also be approximately uniform.

[0356] because Figure 22C The spacing of the optical channels, and the overlapping of illumination areas 2616, such as... Figure 22C The overlapping region 2618 is shown in the diagram. Because the image produced by the lens in illumination region 2616 is typically larger than the corresponding area of ​​the associated lens and other optical elements in the optical channel, the overlapping region 2618 may occur. The overlapping region 2618 can indicate optical crosstalk between adjacent optical channels and can introduce a non-uniform image region that reduces the effective size of the usable image not contaminated by crosstalk from other channels. For example, Figure 22C Rectangular regions of different sizes are depicted, with overlapping regions 2618 set around each rectangular region. The rectangular regions can define a usable image area 2615 for imaging objects (such as gas clouds).

[0357] For example, the first optical channel transmits light to the portion of the optical detector 2610 corresponding to illumination region 2616A. Adjacent optical channels also transmit light within illumination regions 2616B, 2616C, and 2616D. However, because the optical channels are very close together, light from illumination regions 2616B and 2616D can enter the adjacent illumination region 2616A, and vice versa. This results in... Figure 22C The multiple overlapping regions 2618 shown.

[0358] exist Figure 22C In the illustrated arrangement, each optical channel 2602 further defines a detection area 2612 of the optical detector 2610. Each detection area 2612 comprises a square, the center of which may coincide with the optical axis or central axis passing through the lens assembly corresponding to the optical channel. The detection areas 2612 may include multiple pixels and may be spatially separated from each other. For example, in the illustrated arrangement, the detection areas 2612 may be separated by approximately 0.136 mm and may have a size of 4.25 mm by 4.25 mm. In some embodiments, the illumination area 2616 may have a diameter of 6.01 mm.

[0359] Therefore, the illumination area 2616 of a particular channel can extend beyond the detection area 2612 of that channel and into the detection area 2612 of an adjacent channel, thereby creating an overlapping area 2618. The overlapping area 2618 can thus indicate optical crosstalk between optical channels 2602. While specific example dimensions have been described above, these dimensions are not limiting and are merely one example of the optical detector 2610. For example, the detection area 2612 can have a width or height in the range of approximately 3 mm to approximately 6 mm, or in the range of 3.5 mm to 5 mm, for example, approximately 4.250 mm in the illustrated embodiment. The usable image area 2615 can have a height in the range of approximately 2 mm to 6 mm, for example, in the range of 2 mm to 5 mm, or in the range of 2 mm to 4 mm. The usable image area 2615 can have a width in the range of approximately 2 mm to 5 mm, for example, in the range of 2 mm to 4 mm. However, the design of the lens assembly 2702 can be modified to provide a larger (or smaller) surface area for each usable area 2615.

[0360] like Figure 22CAs shown, in some arrangements, the available image region 2615 at the detector 2610 may be non-uniform. For example, for an illumination region 2616 (such as illumination region 2616A) in an inner region of the detector 2610, the overlapping region 2618 may reduce the available image region 2615A to a greater extent than adjacent available image regions 2615B, 2615C, and 2615D. In other words, image regions 2615B-2615D may be larger than image region 2615A. Furthermore, image region 2615C may be larger than image regions 2615B and 2615D, because image region 2615C is disposed at a corner of the detector 2610, such that image overlap 2618 is only present on two sides of the detection region 2612. In comparison, image regions 2615B and 2615D have a size that is reduced by image overlap 2618 on three sides of the detection region 2612, and image region 2615A has a size that is reduced by image overlap 2618 on four sides of the detection region 2612.

[0361] Accordingly, different shapes and contours of image regions 2615A-2615D produce non-uniform image regions at the detector 2610. In Figure 22C arrangements, the maximum image size at the detector 2610 may be limited by the smallest available image region 2615 on the detector 2610, for example, the image region 2615A of the detector 2610. For example, in the illustrated arrangement, the available image region 2615A may be 162 pixels along the x-direction and 162 pixels along the y-direction, which can represent the maximum available area for imaging on the detector 2610. To improve the image quality and gas detection capability of the system 1000, it may be important to increase the available image region 2515 of the detector 2610.

[0362] Figure 22D depicts an illumination region 2616 that indicates light transmitted from an object to an optical detector, wherein a lens assembly may be configured to increase the available image region at the optical detector 2610 with reduced vignetting. Figure 22E is a front plan view of an exemplary lens assembly 2702, the lens assembly being sized to transmit radiation to Figure 22D the illustrated illumination region 2616. Similar to the arrangement of Figure 22C , Figure 22D each illumination region 2616 may represent a region at the optical detector 2610 that receives light from a corresponding optical channel and associated lens. The illumination region 2616 may be larger than a corresponding lens in the optical channel 2602. As explained above, due to the spacing of the optical channels 2602, the illumination regions 2616 overlap, as indicated by overlapping region 2618. The overlapping region 2618 may indicate optical crosstalk between adjacent optical channels. As with Figure 22CThe overlapping region 2618 can define the usable image region 2615, which is in Figure 22D The middle part is rectangular (e.g., approximately square). In Figure 22D In the illustrated implementation, these available image regions 2615 have approximately the same size, unlike in... Figure 22C In the illustrated implementation, the detection area towards the center of the focal plane array is smaller than the detection area around the periphery of the focal plane array.

[0363] exist Figure 22D and Figure 22E In the implementation plan, with Figure 22C Compared to the previous arrangement, the lens assembly 2702 can be designed to increase the usable image area 2615. The optical characteristics and positions of the various optical elements in the lens assembly 2702 influence each other and affect the resulting usable area 2615. For example, with Figure 22C Compared to the optical channel 2602 that forms a usable image region 2615, Figure 22E The optical channels 2602 (e.g., lenses 2504, 2506, 2508) can be spaced further apart. For example, the horizontal (center-to-center) spacing dx between adjacent lenses in lens assembly 2702 can be in the range of 2 mm to 6 mm. The vertical (center-to-center) spacing dy between adjacent lenses in lens assembly 2702 can be in the range of 2 mm to 6 mm. The horizontal spacing dx can be the same as or different from the vertical spacing dy. In some embodiments, the spacings dx and dy can be smaller near the center of detector 2610 and can gradually increase near the edges of detector 2610. This arrangement can shift the available image area 2615 further apart to reduce optical crosstalk and increase the area of ​​each available area 2615. In other arrangements, the spacings dx and dy can be substantially uniform across lens assembly 2702. In other arrangements, the spacings dx and dy can be larger near the center of detector 2610 and gradually decrease near the edges of detector 2610, which can reduce optical crosstalk and / or increase the area of ​​each available area 2615. Figure 22D The available image area 2615 may have a width in the range of 2.5mm to 5mm, in the range of 3mm to 4mm, in the range of 3mm to 3.5mm, for example, approximately 3.357mm. Figure 22D The available image area 2615 can have a height in the range of 3mm to 4mm, for example, about 3.523mm. Figure 22D Image area 2615 can be 9mm 2 Up to 16mm 2 Within the range, or within 9mm 2 Up to 13mm 2 Within the range.

[0364] Furthermore, the optical detector 2610 may include an effective imaging region 2610A, which includes effective imaging elements or pixels for acquiring image data from IR radiation transmitted to the detector 2610. For example, the effective imaging region 2610A may include a region on the detector 2610 comprising effective pixels for sensing an image processed by processing electronics to detect a target substance. In some embodiments, the effective imaging region 2610A may include all or substantially all of the area of ​​the detector 2610. In other embodiments, the effective imaging region 2610A may be significantly smaller than the total area of ​​the front surface of the detector 2610. Figure 22E In the illustrated embodiment, the effective imaging region 2610A of the detector may include a total effective imaging area A. I The total effective imaging area can be determined by the horizontal width D of the effective imaging region 2610A. x and vertical height D y Limitations (e.g., A) I =D x *D y Similarly, lens assembly 2702 can define an optical coverage area A representing the approximate lateral coverage of lens assembly 2702. O In the illustrated implementation, the optical coverage area A O The horizontal coverage of L can be achieved by lens assembly 2702 x and vertical coverage L y Limitations (e.g., A) O =L x *L y ).like Figure 22E As shown, the horizontal coverage L can be defined based on the outermost lateral extent of the lens assembly 2702. x Similarly, vertical coverage L y It can be defined based on the vertical outermost range of the lens assembly 2702, such as Figure 22E As shown.

[0365] exist Figure 22E In the implementation plan, the optical coverage area A O It can be larger than the effective imaging area A I Furthermore, the lens assembly 2702 may define N optical channels 2602, each channel 2602 imaging a beam or spot size area A on the detector 2610 that is slightly larger than the diameter or lateral dimension of the associated lens. b .exist Figure 22E In the middle, the area of ​​the light spot is A b It is shown as extending together with optical channel 2602, but it should be understood that the spot size area A b This can differ due to factors such as diffraction. The total beam area A of the light striking the detector.T It can be calculated based on the portion of each beam or channel impacting the effective area of ​​detector 2610. Total beam area A T It can be smaller than the effective imaging area A I In other words, there may be an effective imaging area A that does not receive light from lens assembly 2702. I The region. Total beam area A T It can be smaller than the total effective imaging area A I 98%. In various implementation schemes, the total beam area A T It can be smaller than the total effective imaging area A I 95%, less than the total effective imaging area A I 90% or less than the total effective imaging area A I 75%. In some implementations, the total beam area A T In total effective imaging area A I Within the range of 50% to 98% of the total effective imaging area A I Within the range of 55% to 75%, or within the range of 57% to 67% of the total effective imaging area, for example, the total effective imaging area A I Approximately 62%. In some implementations, the effective imaging area A I It can be smaller than the optical coverage area A O 98%, less than the optical coverage area A O 95%, less than the optical coverage area A O 90%, less than the optical coverage area A O 85%, less than the optical coverage area A O 80% or less than the optical coverage area A O 75%. In some implementations, the effective imaging area A I It can be used in optical coverage area A O Within the range of 50% to 98%, in optical coverage area A O Within the range of 65% to 95%, or in the optical coverage area A O The range is between 55% and 65% (e.g., approximately 62%).

[0366] exist Figure 22D and Figure 22E In the illustrated embodiment, the optical channels are spaced apart, causing the detector regions 2612 to be spatially close together (e.g., spaced approximately 0.136 mm apart in some embodiments), while also increasing or maximizing the size of the available area 2615. Figure 22D and Figure 22EAs shown, optical channel 2602 can be configured such that available areas 2615 are spaced apart in a non-uniform spatial arrangement, but have a generally uniform size. For example, starting from the central available area 2615A, available areas 2615 can be designed to move progressively closer to one or more edges of their detector area 2612 and progressively further away from adjacent available areas 2615. Advantageously, Figure 22E The size design of the lens assembly 2702 can increase the effective usable imaging area 2615 by reducing the overlap area 2618 and crosstalk.

[0367] For example, based on the location of each available area 2615 as described above and / or the positioning of baffles 2620 and 2630, the available area 2615 may have a width and length in the range of approximately 3 mm to 4 mm, for example, approximately 3.523 mm by 3.357 mm, such as... Figure 22D The implementation scheme is shown. This can correspond to the number of available pixels within each available area 2615, for example, 207 pixels multiplied by 197 pixels, which is greater than... Figure 22C The usable area 2615 is approximately 55%. Although specific examples of the usable area 2615 and lens assembly 2702 have been described herein, the usable area 2615 and lens assembly 2702 can be modified and / or optimized for any suitable application. The lens assembly 2702 described above is merely one embodiment, and the optical characteristics of the components within the lens assembly 2702 can be modified as needed for any other suitable type of imaging application.

[0368] In some implementations, baffles 2620 and 2630 (as described above) are included. Figure 22B The aforementioned ( ) may be advantageous, as the baffle can be at least partially based on Figure 22D The available area 2615. For example, baffles 2620 and 2630 can be configured such that light is transmitted to optical detector 2610 within the available area 2615 while substantially blocking stray light that would otherwise be transmitted to optical detector 2618 within the overlapping area. In various embodiments, baffles 2620, 2630 can remove light from the overlapping area such that the irradiance at or near the edges of the image area is close to zero (or otherwise negligible). In various embodiments, the baffles can define the overlapping area. For example, baffles 2620 and 2630 can be configured such that at the center 2617A of the available area 2615 (see...) Figure 22D The amount of light received is relatively greater than at the edge 2617B (see Figure 22D The amount of light received. Therefore, baffles 2620 and 2630 can be configured to cause the relative intensity of light on the available area 2615 to decrease as a function of distance from the center 2617A (e.g., as...). Figure 22F(As shown), hereinafter referred to as "intensity roll-off". In some embodiments, the intensity roll-off can be a relative roll-off, where the amount of light at the edge 2617B is controlled relative to the amount of light at the center 2617A. For example, the amount of light at the center can be considered 100%, and the amount of light at the edge 2617B can be designed to roll off to approximately 0%. Thus, each available area 2615 can indicate an image corresponding to an optical channel that is substantially independent of or unaffected by the light crossing between adjacent optical channels.

[0369] In various embodiments, the optical detector 2601 may include a detector array comprising a single FPA or an array of FPAs. In various embodiments, the optical detector 2601 may include multiple photosensitive devices. In some embodiments, the multiple photosensitive devices may include a two-dimensional imaging sensor array that is sensitive to radiation having wavelengths between 1 μm and 20 μm (e.g., in the near-infrared, mid-infrared, or long-infrared wavelength range). In various embodiments, the multiple photosensitive devices may include CCD or CMOS sensors, calorimeters, microbolometers, or other detectors sensitive to infrared radiation.

[0370] Although they have combined Figures 22B to 22G A specific embodiment of lens assembly 2702 has been described; however, it should be understood that lens assembly 2702 can be designed for any suitable application. Lens assembly 2702 and the usable area 2615 created therefrom are one embodiment described in conjunction with various DAISI systems (e.g., DAISI systems can be mobile or fixed). However, the optical components within lens assembly 2702 and the positions of these components (e.g., the number, size, and position of apertures and stops) can be modified as needed in conjunction with any other suitable type of imaging application. For example, lens assembly 2702 can be used with any suitable type of infrared imaging system or camera to control stray light to maintain the optical performance of the system. Based on the desired application, the lens assembly can be configured or optimized for any specific application with any desired components.

[0371] Figure 22F yes Figure 22D Example simulation of intensity roll-off over available region 2615. Figure 22FThe relative illumination (e.g., intensity) at optical detector 2610 is shown as a function of position on the available area 2615 (denoted as line 2695). For example, the horizontal axis represents the position from center 2617A in mm. Line 2695 can represent any line extending between center 2617A and edge 2617B (e.g., along a horizontal or vertical line, or along a line at an angle to a horizontal or vertical line). In some embodiments, line 2695 represents the intensity roll-off of image vignetting based on optical detector 2610. In some embodiments, image vignetting can be caused by baffles 2620 and / or 2630 in lens assembly 2702. Simulation results can be obtained using optical simulation software (e.g., FRED). TM Software) obtained.

[0372] Figure 22F This shows the combination above. Figure 22D and Figure 22E In the described implementation, the light received at the edge of the usable area 2615 decreases to 0 relative to the maximum detection intensity or illuminance. For example, at the center 2617A of the usable area 2615A (0 mm on graph 2690), the photodetector 2610 receives a certain amount of light. The amount of light can be normalized to provide a maximum value of 1.0 (or 100%). Although Figure 22F The example shown depicts the maximum value at center 2617A, but normalization does not need to be at center 2617A and can be located elsewhere on the available area 2615.

[0373] As described above, the simulated measurement is the amount of light received in the available area 2615 relative to the amount of light received at the center 2617A. Figure 22F It is shown that the amount of light received at edge 2617B can be reduced to approximately 0.01% (or 0.1%) of the amount of light received at center 2617A. The reduction of stray light at edge 2617B can be based on implementing one or more baffles in baffles 2620 and / or 2630 and optimizing lens assembly 2702, as described above. Figure 22D and Figure 22C As described above. For example, a quality factor can be evaluated when various parameters of the lens assembly, including the selection of lens surface curvature, lens position, lens thickness, and the number, size, and position of apertures / stops, are varied to determine a suitable design with appropriate vignetting. The quality factor may, for example, take into account vignetting and / or its effects. In some embodiments, stray light can be substantially blocked from crossing between optical channels, at least in part based on baffles 2620 and / or 2630.

[0374] Figure 22G An exemplary vignetting of an image of scene 2720 is shown. Figure 22GThe simulated available area 2715 (denoted as a square) is shown, which is essentially similar to... Figures 22D to 22E Available area 2615. For example... Figure 22G As shown, the image contained within the usable area appears sharper and clearer, while the portion of the image outside the usable area 2715, 2720, is darker. The darkening of the image 2720 at the edges indicates that the image is vignetted to reduce or block light received at the edge 2715b of the image without sacrificing the sharpness or performance of the lens assembly 2702 at the center 2715a of the image 2720.

[0375] In the embodiments disclosed herein, the lens assembly 2702 comprises lenses or lens elements 2504, 2506, 2508 (see herein) Figure 18D The lens assembly 2702 can be manufactured to meet precise tolerances, which can significantly improve the performance of system 1000. The lens assembly disclosed herein can be advantageously designed by selecting the tolerances for each individual lens in the assembly, and by selecting tolerances that are considered as a whole for the lens assembly 2702 (e.g., by taking into account lens manufacturing errors, baffle dimensional errors, etc.). For example, the embodiments disclosed herein can utilize one or more of the square root of the sum of squares (RSS) and Monte Carlo techniques to select lens tolerances. Tolerances can be selected such that a root mean square (rms) spot size greater than or equal to 90% is smaller than the diffraction-limited Airy disk of the imaging spot. Such relatively conservative standards can ensure improved system performance, which can also be achieved using the manufacturing techniques disclosed herein.

[0376] The lens assembly 2702 disclosed herein can be designed and manufactured to have a very low f-number (f / #) for each optical channel. The low f-number system disclosed herein can advantageously and significantly improve the system sensitivity for each optical channel (e.g., by at least about 44%). For example, in some embodiments, the lens can be designed for system 1000 to achieve an f / 1 for each channel, wher...

Claims

1. A thermal imaging system, comprising: An infrared (IR) imager comprising an array of focal plane arrays (FPAs), the IR imager being configured to acquire IR image data of the field of view of the IR imager; A video analysis circuitry system, operatively coupled to the IR imager, wherein the video analysis circuitry system is configured to: Receive first temperature data of a first field reference within the field of view of the IR imager; Receive second temperature data of a second field reference within the field of view of the IR imager; IR image data is received from the IR imager, the IR image data including first IR image data of the first field reference and second IR image data of the second field reference; and The IR imager is calibrated based on the first temperature data, the second temperature data, and the IR image data, wherein, for calibrating the IR imager, the video analysis circuitry is further configured to: The uncertainty of the IR imager is determined based on a first comparison between the first temperature data and the first IR image data of the first field reference, and a second comparison between the second temperature data and the second IR image data of the second field reference, wherein the first field reference and the second field reference are used to reference and stabilize the first IR image data and the second IR image data from the IR imager by providing spectrally known and time-stable objects in each scene, thereby achieving dynamic compensation in the system; as well as The first and second field references are set to different temperatures to record the absolute value of the difference between the arrays of the FPA of the IR imager at a temperature, and how the difference changes with temperature, thereby providing more information for calibration. One or more temperature control elements are thermally coupled to the IR imager and configured to modify the operating temperature of the IR imager based on uncertainties in the IR imager.

2. The thermal imaging system of claim 1 further includes a temperature control chamber, the temperature control chamber enclosing the IR imager and configured to thermally isolate the IR imager.

3. The thermal imaging system according to claim 2 further includes a lens of the IR imager, the lens forming an interface between the temperature control chamber housing the IR imager and the external environment.

4. The thermal imaging system according to claim 3 further includes a thermally conductive mechanical gasket supporting the lens.

5. The thermal imaging system of claim 1, wherein the video analysis circuit system is configured as follows: The detection confirms that neither the first field reference nor the second field reference exists within the field of view of the IR imager; and Generate a user notification requesting repositioning of the IR imager.

6. The thermal imaging system of claim 1, further comprising one or more temperature sensors thermally coupled to the IR imager, wherein the video analysis circuitry is further configured to: Receive operating temperature data from the one or more temperature sensors; and The operating temperature based on the said operating temperature data will be compared with one or more operating thresholds; and If the operating temperature does not meet one or more operating thresholds, the operating temperature of the IR imager is modified.

7. The thermal imaging system of claim 1, further comprising a remote video sensor supporting the IR imager and the visible light imager, the visible light imager being configured to acquire visible light image (VIS) data of the field of view of the remote video sensor, wherein the video analysis circuitry is further configured to: Receive the VIS data from the visible light imager; Receive the IR image data from the IR imager; Analyze VIS data to determine one or more target indication identifiers associated with one or more faces within the field of view of the remote video sensor; Map the one or more target indication identifiers onto the IR image data to generate a target-modified IR image; Analyze the modified IR image of the target to determine the facial temperature associated with each of the one or more faces within the field of view; and Generate an IR image including the one or more target indication identifiers and the target and temperature modifications of the facial temperature.

8. The thermal imaging system of claim 7, wherein the VIS data from the visible light imager further includes VIS time data, and the IR image data from the IR imager further includes IR time data, such that the video analysis circuitry is further configured to correlate the VIS data and the IR image data based on the VIS time data and the IR time data.

9. The thermal imaging system of claim 7, wherein determining the one or more target indication identifiers of the VIS data further comprises determining one or more facial attributes of the one or more faces within the field of view of the remote video sensor.

10. The thermal imaging system of claim 9, wherein analyzing the target-modified IR image to determine the facial temperature further includes determining a facial temperature associated with or defined by the one or more facial attributes.

11. The thermal imaging system of claim 7, wherein the video analysis circuitry is further configured to display the target and a temperature-modified IR image.

12. The thermal imaging system of claim 9, wherein the one or more facial attributes include at least one of the mouth, nose, eyes, or tear ducts of the one or more faces within the field of view of the remote video sensor.

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