Supplementary flat field correction determination for infrared imaging systems and methods

Abstract

Techniques are provided for facilitating assisted flat field correction (SFFC) determination for infrared imaging systems and methods. In one example, a method includes capturing, by a focal plane array (FPA) of an imaging system, a first set of images of a first reference object in a scene while the first reference object is at a temperature associated with a second reference object while the first set of images is captured. The method further includes capturing, by the FPA, a second set of images of a second reference object. The method further includes determining an SFFC value based on the first set of images and the second set of images. Related devices and systems are also provided.

Description

Cross-references to related applications

[0001] This application claims priority and benefit to U.S. Provisional Patent Application No. 63 / 578,560, filed August 24, 2023, entitled “Supplemental Flat Field Correction Determination for Infrared Imaging Systems and Methods,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] One or more embodiments generally relate to imaging, and more specifically, for example, to the determination of supplemental flat field correction (SFFC) for infrared imaging systems and methods. Background Technology

[0003] Imaging systems may include arrays of detectors arranged in rows and columns, each detector serving as a pixel to generate a two-dimensional image. For example, individual detectors in the array capture relevant pixel values. A wide variety of image detectors exist, such as visible light image detectors, infrared image detectors, or other types of image detectors, which can be arranged in an image detector array to capture images. As an example, multiple sensors can be arranged in an image detector array to detect electromagnetic (EM) radiation at a desired wavelength. In some cases, such as for infrared imaging, the readout of image data captured by the detectors can be performed by a readout integrated circuit (ROIC) in a time-division multiplexing manner. The readout image data can be transferred to other circuitry, such as for processing, storage, and / or display. In some cases, the combination of detector arrays and ROICs can be referred to as a focal plane array (FPA). Advances in process technologies used for FPAs and image processing have led to increased capabilities and complexity in the resulting imaging systems. Summary of the Invention

[0004] In one or more embodiments, a method includes: capturing a first set of images of a first reference object in a scene using an imaging system's field-amplifier (FPA), while the first reference object is at a temperature associated with a second reference object during the capture of the first set of images. The method further includes: capturing a second set of images of the second reference object using the FPA. The method also includes: determining an SFFC value based on the first set of images and the second set of images.

[0005] In one or more embodiments, an imaging system includes an image processing unit (FPA) configured to capture a first set of images of a first reference object in a scene, wherein the first reference object is at a temperature associated with a second reference object when the first set of images is captured. The FPA is also configured to capture a second set of images of the second reference object. The imaging system further includes logic devices configured to determine an SFFC value based on the first and second sets of images.

[0006] In one or more embodiments, a method includes: capturing a first set of images of a first reference object in a scene using an imaging system's field-aperture sensor (FPA). The method further includes capturing a second set of images of a second reference object using the FPA, wherein the second reference object is at a temperature associated with the FPA while the second set of images is being captured. The method also includes: determining an SFFC value based on the first and second sets of images.

[0007] The scope of this disclosure is defined by the claims, which are incorporated herein by reference. A more thorough understanding of embodiments of this disclosure will be provided to those skilled in the art, and their other advantages will be recognized, by considering the following detailed description of one or more embodiments. Reference will be made to the accompanying drawings, which will first be briefly described. Attached Figure Description

[0008] Figure 1 An infrared camera according to one or more embodiments of the present disclosure is shown; Figure 2 and Figure 3 A flowchart illustrating an example process for determining an SFFC value according to one or more embodiments of the present disclosure is shown; Figure 4 A flowchart illustrating an example process for applying SFFC values ​​to captured image data according to one or more embodiments of the present disclosure is shown; Figure 5 and Figure 6 An example display screen showing a dialog box is shown for facilitating the calibration of an infrared camera according to one or more embodiments of the present disclosure; Figure 7 A block diagram of an example imaging system according to one or more embodiments of the present disclosure is shown; Figure 8 A block diagram of an example image sensor assembly according to one or more embodiments of the present disclosure is shown.

[0009] The embodiments and advantages of this disclosure are best understood by referring to the following detailed description. It should be noted that the dimensions of the various components and the distances between them in the figures are not drawn at scale. It should be understood that the same reference numerals are used to identify one or more of the same elements shown in the figures. Detailed Implementation

[0010] The detailed description set forth below is intended to describe various configurations of the present technology and is not intended to represent the only configuration in which the present technology may be implemented. The accompanying drawings are incorporated herein and form part of the detailed description. The detailed description contains specific details and is intended to provide a thorough understanding of the present technology. However, it will be clear and apparent to those skilled in the art that the present technology is not limited to the specific details set forth herein and may be implemented using one or more embodiments. In one or more instances, structures and components are shown in block diagram form to avoid obscuring the concept of the present technology. One or more embodiments of this disclosure are illustrated and / or described in conjunction with one or more accompanying drawings and are set forth in the claims.

[0011] Various techniques provide supplemental flat-field correction determinations for infrared imaging systems and methods. Imaging systems can be used to capture image data associated with a scene using image sensor devices (e.g., detector arrays of an FPA). Image sensor devices include detectors (e.g., also referred to as detector pixels, detector elements, or simply pixels). Each detector pixel can detect incident EM radiation and generate infrared image data indicating the detected EM radiation of the scene. In some embodiments, the image sensor array is used to detect infrared radiation (e.g., thermal infrared radiation). For a pixel in an infrared image (e.g., a thermal infrared image), each output value of the pixel can be represented / provided as and / or corresponding to temperature, a digital count value, a percentage of the full temperature range, or any value that can generally be mapped to temperature. For example, a digital count value of 13000 output by a pixel can represent a temperature of 160ºC. Therefore, the captured infrared image data can indicate or be used to determine the temperature of objects, people, and / or other features / aspects in a scene.

[0012] In some cases, infrared imaging systems (e.g., thermal cameras) can represent infrared image data in an image using a color palette. The color palette can provide a mapping from different output levels to visual representation values. The color palette can be applied to image data values ​​output by the image sensor device of the infrared imaging system (e.g., based on detected EM radiation) to generate an image. In this respect, the image can be viewed as a visual representation of the image data values. The visual representation values ​​of the color palette can include color values ​​and / or grayscale values. In some cases, the visual representation values ​​can facilitate scene analysis by one or more users of the infrared imaging system and / or the circuitry of the infrared imaging system (e.g., machine vision) and / or other machines.

[0013] During startup (e.g., initial power-on) or other internal heating processes, the infrared imaging system heats up. As an example, the startup process may end after approximately five minutes (e.g., approximately five minutes after startup begins, a steady state begins). After startup, the temperature and rate of temperature change associated with the components of the infrared imaging system are typically caused by external factors (e.g., temperature changes outside the infrared imaging system) rather than by internal heating of the infrared imaging system. External temperatures may include ambient temperature and / or the temperatures of one or more objects in the scene. As an example of internal heating processes other than startup, internal heating may be caused by changes in the operating mode of the infrared imaging system, such as changes in the frame rate associated with the FPA, which may lead to changes in internal heating. As another example, turning on / off or otherwise altering power-consuming electronics (e.g., electronics near the FPA) may also cause internal heating. For example, changes in image processing on a processor thermally coupled (e.g., tightly thermally coupled) to the FPA may cause internal heating.

[0014] In some embodiments, an infrared imaging system may refer to operation in an activation state / mode (e.g., also referred to as a transient state / mode) and a steady-state state / mode (e.g., also referred to as an equilibrium state / mode). The amount of time the infrared imaging system spends operating in the activation and steady-state modes may be partly based on the ambient temperature (e.g., the temperature of the room where the infrared imaging system is located). For example, an infrared imaging system activated at a colder ambient temperature may operate in activation mode for a longer time compared to being activated at a warmer ambient temperature. During the activation state, the infrared imaging system exhibits significant internal heat generation (e.g., due to the power-on of the various components of the infrared imaging system). To reach a steady-state state, the infrared imaging system may be activated and kept activated until it exhibits steady-state behavior. Once the infrared imaging system transitions from operation in the activation state to operation in the steady-state state, it exhibits steady-state behavior, where the temperature and / or temperature changes of one or more components of the infrared imaging system are primarily caused by external factors (e.g., temperature changes outside the infrared imaging system).

[0015] In some embodiments, an infrared imaging system (e.g., its FPA) can be calibrated by capturing images of one or more reference objects / sources and using these captured images to determine SFFC values. The reference object can be a thermal blackbody, or can be considered a thermal blackbody. Digital imaging can be used to perform SFFC value determination associated with the FPA to eliminate artifacts from images captured by the FPA caused by pixel-to-pixel variations in the FAP's output (e.g., variations between individual detectors) and / or distortions in the optical path. In some aspects, the infrared imaging system may include an internal reference object (e.g., also referred to as an internal structure) that can be used in determining the SFFC value. In some cases, the internal reference object may refer to a reference object within the housing of the infrared imaging system. By way of non-limiting examples, the internal structure may include a shutter, cover, hood, or paddle. For calibration, the FPA of the infrared imaging system may capture a set of images (e.g., infrared images, such as thermal infrared images) of the reference object in a scene (e.g., an external scene), and / or capture a set of images of the internal reference object when it is positioned above the FPA to block the FPA from seeing the scene. By way of non-limiting example, an external source / object may include the housing or sleeve of an imaging system, a lens cover, a shroud, a room wall, or other suitable object / surface.

[0016] Infrared imaging systems can be recalibrated as needed (e.g., runtime / field recalibration) to maintain SFFC values ​​that keep pace with the characteristics of the FPA (e.g., pixel-to-pixel output variations and / or distortions in the optical path) at the time of recalibration. In some cases, the user of an infrared imaging system may recalibrate the system when one or more components are adjusted. By way of non-limiting examples, adjustments to an infrared imaging system may include modifications that significantly alter the thermodynamics of the system, such as: the user attaching thermal mass to the shutter and / or lens; replacing the housing of the infrared imaging system; adjusting the arrangement of one or more elements (e.g., optical elements); cutting in or out one or more elements, etc.

[0017] In some aspects, the infrared imaging system may include audio and / or visual devices (e.g., a display, one or more indicator lights) for providing audio and / or visual feedback to prompt or otherwise facilitate recalibration of the infrared imaging system. In some cases, the infrared imaging system may be coupled to a user device (e.g., via an app installed on the user device), such as a mobile device, desktop computer, etc., which has audio and / or visual devices for providing audio and / or visual feedback. In some cases, feedback may be manually triggered by the user (e.g., the user presses a button to initiate a calibration process), and / or autonomously triggered by the infrared imaging system in response to: by a non-limiting example, the amount of time since the previous calibration exceeds a threshold time (e.g., set by the manufacturer or user); changes in the operating conditions of the infrared imaging system (e.g., ambient temperature); and / or user alterations to components of the infrared imaging system (e.g., removing or adding lenses) and / or changes to functional parameters (e.g., changing the frame rate or gain mode).

[0018] In some embodiments, to facilitate calibration / recalibration, a user interface may be presented on the display device of the infrared imaging system or on a display device otherwise connected to the infrared imaging system to provide guidance / instructions and / or data to the user. For example, the user interface may indicate the temperature of the FPA of the infrared imaging system and instruct the user to set the temperature of a reference object to the temperature of the FPA (e.g., for calibration / recalibration purposes).

[0019] In some respects, calibration can be performed at the factory (e.g., as part of the manufacturing process before delivery to the customer) to determine the SFFC values ​​of an initial group associated with the FPA of the infrared imaging system, and the SFFC values ​​of this initial group can be stored in the infrared imaging system's memory or in memory otherwise accessible to the infrared imaging system. For example, the SFFC values ​​of the initial group may be associated with the factory / default settings of the infrared imaging system. Runtime / field calibration can be performed (e.g., performed by the operator of the infrared imaging system) to adjust / update or overwrite the SFFC values ​​of the initial group and / or the SFFC values ​​of one or more previous groups determined during the runtime / field calibration. In some cases, the SFFC values ​​of the initial group and / or the SFFC values ​​of one or more other groups may remain stored in memory, for example, to allow the user of the infrared imaging system to revert to previous settings of the infrared imaging system. For example, the SFFC values ​​of the initial group may remain stored in memory to allow the user of the infrared imaging system to revert to factory settings (e.g., at least in terms of SFFC values).

[0020] While various embodiments have been described primarily with respect to infrared imaging (e.g., thermal infrared imaging), the methods and systems disclosed herein can be used in conjunction with devices and systems such as imaging systems with visible and infrared imaging capabilities, shortwave infrared (SWIR) imaging systems, light detection and ranging (LIDAR) imaging systems, radar detection and ranging (RADAR) imaging systems, millimeter-wave (MMW) imaging systems, ultrasound imaging systems, X-ray imaging systems, microscope systems, mobile digital cameras, video surveillance systems, video processing systems, or other systems or devices that may require image data in one or more portions of the EM spectrum.

[0021] Now refer to the attached diagram, Figure 1 An infrared camera 100 according to one or more embodiments of the present disclosure is shown. The infrared camera 100 includes an infrared detector package 106, a motor 108, a shutter 110, a power supply block 114, an optics block 116, a processing and control block 120, one or more temperature sensors 128, and an optional window 170.

[0022] In one example, infrared camera 100 can represent any type of infrared camera or thermal imaging system, not limited to any specific embodiment disclosed herein, and can be implemented according to the needs of a particular application. Therefore, in one embodiment, Figure 1 The component shown can be implemented as a stand-alone infrared camera. In another embodiment, Figure 1 The components can be distributed across multiple different devices. For example, the processing and control block 120 can be implemented by one or more external computer systems connected to the infrared camera 100 (e.g., via a network or other suitable communication medium). In another embodiment, the infrared camera 100 can be suitably used for a specific application. Figure 1 The components shown can be implemented with more, fewer, and / or different components.

[0023] Infrared energy received from scene 180 in front of infrared camera 100 travels along optical path 150 through optical element block 116 (e.g., optics containing one or more elements for guiding and / or focusing infrared radiation onto infrared detector package 106) to infrared detector package 106 (e.g., a vacuum-sealed assembly). In one embodiment, infrared detector package 106 and optical element block 116 may be sealed within a chamber (not shown) including a window 170 (e.g., a heated or temperature-controlled protective window) located between optical element block 116 and scene 180. Optical element block 116 may include one or more windows, lenses, mirrors, beam splitters, beam couplers, and / or other components. In this respect, optical element block 116 may include components made of various materials, and these components are designed according to desired transmission characteristics (e.g., desired transmission wavelengths (e.g., at least...). Figure 1 The infrared wavelength and / or ray transmission matrix characteristics are appropriately arranged.

[0024] Infrared detector package 106 includes an array detector array (FPA) 104 to detect infrared radiation passing through window 105 (e.g., a vacuum-sealed window) and, in response, provide thermal image data. FPA 104 includes a detector array and readout circuitry. The detector array can be implemented using various types of infrared detectors (e.g., quantum wells, microbolometers, or other types) depending on the specific implementation requirements. Optical component block 116 can receive electromagnetic radiation from scene 180 and direct (e.g., guide and / or focus) that electromagnetic radiation to FPA 104. In some cases, optical component block 116 can receive electromagnetic radiation from scene 180 through the aperture of infrared camera 100. FPA 104 can receive electromagnetic radiation from optical component block 116 and generate image data based on that electromagnetic radiation (e.g., the infrared component of the electromagnetic radiation).

[0025] The image data may include infrared data values ​​(e.g., thermal infrared data values). As an example, FPA 104 may include or be coupled to an analog-to-digital converter (ADC) circuitry that generates infrared data values ​​based on infrared radiation. For example, a 16-bit ADC circuitry may generate infrared data values ​​ranging from 0 to 65535. The infrared data values ​​can provide the temperature of different parts of a scene, such as the temperature of objects, people, and / or other aspects in scene 180. In some cases, the infrared image data may be presented in the image according to a color palette, such that the visual representation value (e.g., color value or grayscale value) of each pixel in the image indicates the temperature associated with that pixel. For example, the temperature associated with an object in scene 180 may be represented in the pixels (e.g., a subset of pixels) corresponding to that object in the infrared image (e.g., a thermal infrared image). The infrared image data may be displayed (e.g., shown to a user), stored, and / or processed.

[0026] To calibrate FPA 104, a thermal blackbody 126 can be positioned in scene 180 such that the thermal blackbody 126 is aligned (e.g., covering, overlapping) with the field of view (FOV) of the infrared camera 100. The thermal blackbody 126 can be completely aligned with the FOV of the infrared camera 100. In some cases, by operating the infrared camera 100 in a thermally stable environment (e.g., corresponding to a thermally stable state such as room temperature) and capturing a thermal image of the thermal blackbody 126, an FFC value can be determined, which can be applied to the thermal image data received from FPA 104 to correct for non-uniformities (e.g., thermal load or optical irregularities) present in the optical path 150. As further described herein, alternative or additional steps can be performed to calibrate FPA 104.

[0027] In some cases, infrared camera 100 may reach its steady-state state after being powered on for a period of time (e.g., two minutes, three minutes, ten minutes, etc.). In this regard, for example, the steady-state temperature of a component may refer to the temperature at which the component exhibits no further self-heating or exhibits negligible further self-heating. Different components of infrared camera 100 may be associated with different steady-state temperatures. Infrared cameras with higher heat capacity (e.g., those with larger elements, such as larger lenses) may be associated with different steady-state temperatures for various components (e.g., lower average steady-state temperatures). In some cases, during a power switch where infrared camera 100 is turned off and then quickly turned back on, infrared camera 100 may reach (e.g., return to) its associated steady-state temperature(s) faster than in cases where infrared camera 100 is turned off for a relatively long period (e.g., 20 minutes, 1 hour, or other amounts of time allowing infrared camera 100 sufficient cooling) and then turned back on.

[0028] By operating the motor 108, the shutter 110 can be selectively inserted into the optical path 150 to facilitate the calibration of the FPA 104. For example, in Figure 1 In the illustrated embodiment, shutter 110 is shown inserted into optical path 150. When inserted into optical path 150, shutter 110 substantially blocks infrared radiation from scene 180 from reaching FPA 104. In this case, FPA 104 instead detects infrared radiation received from shutter 110 along optical path 140, excluding infrared radiation received along optical path 160. In one embodiment, shutter 110 may be implemented as a hot blackbody proximal to the front of infrared detector package 106. By calibrating FPA 104 with shutter 110, an FFC value can be determined, which can be applied to the infrared detector of FPA 104 to correct for non-uniformity present in optical path 140 and for non-uniformity in the infrared detector of FPA 104 itself.

[0029] In some cases, one or more elements of the optical component block 116 (e.g., lenses, mirrors, and / or other components) may be selectively inserted into the optical path 150. Therefore, the infrared camera 100 can operate at various focal lengths (e.g., 25mm, 35mm, 50mm, 140mm, or other focal lengths) as needed for a particular application. Different types of optical configurations (e.g., elements, element arrangement, element focal length, etc.) may contribute to different nonuniformities in infrared radiation propagating along the optical path 150. In this regard, in some embodiments, the user of the infrared camera 100 can recalibrate the infrared camera 100 whenever the optical component block 116 is adjusted, such as when one or more elements are removed from, added / inserted into, and / or repositioned in the infrared camera 100. In some aspects, such recalibration can be performed to determine the SFFC value associated with the optical component block 116 after one or more adjustments have been made. In one scenario, the infrared camera 100 may perform recalibration by providing audio and / or visual feedback via an audio device (e.g., a buzzer, speaker) or a visual device (e.g., a display, one or more indicator lights) connected to or otherwise communicatively linked to the infrared camera 100. Such feedback may be manually triggered by the user (e.g., the user presses a button to initiate the calibration process) and / or may be autonomously triggered by the infrared camera 100 in response to detecting a change in the learning device block 116.

[0030] Power block 114 may include a circuit board power subsystem (e.g., a power board) for infrared camera 100. For example, power block 114 may provide various power conversion operations and desired power supply voltages, power-on / power-off switches (e.g., also referred to as on / off switches), and various other operations (e.g., shutter driver for motor 108), including an interface with a battery or external power source, as those skilled in the art will understand.

[0031] Processing and control block 120 includes processor 122 and memory 124. Processor 122 may be configured with suitable software (e.g., one or more computer programs executable by processor 122), stored on machine-readable medium 130 (e.g., CD-ROM or other suitable medium) and / or memory 124, to instruct processor 122 to perform one or more operations described herein. Processor 122 and memory 124 may be implemented according to any desired combination of one or more processors and / or one or more memories, depending on the needs of a particular implementation.

[0032] The processing and control block 120 can receive thermal image data captured by the infrared detector of the FPA 104 and process the thermal image data to perform flat-field correction on the data, thereby taking into account the non-uniformity associated with the infrared detector of the FPA 104 as well as other non-uniformities associated with other parts of the optical path 150 (e.g., non-uniformities associated with the optical component block 116 and / or other parts of the infrared camera 100). The corrected thermal image data can be used to provide a corrected thermal image that takes into account aberrations in the compensated optical path 150.

[0033] The processing and control block 120 can also be connected to the motor 108 to control the insertion and removal of the shutter 110 from the optical path 150. Advantageously, the processing and control block 120 can receive thermal image data captured by the FPA 104 when the shutter 110 is inserted into or removed from the optical path 150. The shutter 110 can be used to provide / present a uniform scene to the detector of the FPA 104. When the shutter 110 is inserted into the optical path 150, the detector of the FPA 104 is effectively blocked from seeing the scene 180. As a result, the processing and control block 120 can selectively calibrate the FPA 104 along the optical path 140 (e.g., when the shutter 110 is inserted into the optical path 150) or along the optical path 150 (when the shutter 110 is removed from the optical path 150). For example, in one embodiment, processing and control block 120 may determine flat-field correction values ​​(e.g., gain and offset values) associated with the individual infrared detectors of FPA 104 to correct for non-uniformity associated with the infrared detectors for optical path 140 or optical path 150. The flat-field correction values ​​may be further processed to determine supplementary FFC values, thereby correcting for non-uniformity associated with optical path 160.

[0034] In some embodiments, the processing and control block 120 may perform operations such as non-uniformity correction (NUC) (e.g., FFC or other calibration techniques), spatial and / or temporal filtering, and / or radiometric conversion on pixel values. As an example, an FFC calibration procedure (e.g., also referred to as an FFC event) may generally refer to a calibration technique performed in digital imaging to eliminate frame artifacts from the frame caused by pixel-to-pixel output variations of the FPA 104 (e.g., variations between individual detectors of the FPA 104) and / or distortions in the optical path.

[0035] The processing and control block 120 may also be connected to one or more temperature sensors 128 to determine the temperature and rate of temperature change of the surrounding environment in which the infrared camera 100 is located and / or one or more components of the infrared camera 100 (e.g., FPA 104, infrared detector package 106, motor 108, shutter 110, power supply block 114, optics block 116, processing and control block 120, window 170, and / or other components). The processing and control block 120 may be configured, in certain circumstances, to scale supplementary FFC values ​​based on temperature readings obtained from the one or more temperature sensors 128.

[0036] One or more temperature sensors 128 may be located at any desired location of the infrared camera 100 (e.g., optical component block 116, FPA 104, mechanical components near optical path 150 (e.g., shutter 110 and / or window 170) and / or other locations of the infrared camera 100), and / or in the surrounding environment where the infrared camera 100 is located. For example, in one embodiment, one or more of the temperature sensors 128 are located on the housing of the infrared camera 100, FPA 104, window 105, window 170 and / or shutter 110 (e.g., shutter lever). In this respect, the temperature sensors 128 may be positioned to appropriately measure and provide temperature readings of various internal components of the infrared camera 100, the exterior of the infrared camera 100 and / or components externally coupled to the infrared camera 100, the surrounding environment, etc. Each temperature sensor may be a thermistor, thermocouple and / or other thermal sensor for measuring temperature. As an example, the infrared camera 100 may be a small camera module containing a single temperature sensor for measuring the temperature of FPA 104. As another example, the infrared camera 100 may include a temperature sensor for measuring the temperature of the FPA 104 and a temperature sensor for measuring the temperature of the lens of the optical component block 116.

[0037] Therefore, for some of these components, the temperature of the component can be directly measured using one or more of the temperature sensors 128. Other components may not have a temperature sensor to measure their temperature. In some cases, the temperature of one or more of these other components can be determined (e.g., estimated, modeled) in part based on temperature data (e.g., temperature measurements) from the temperature sensors 128. For example, a temperature sensor can be placed on FPA 104 to measure the temperature of FPA 104, while no temperature sensor is placed on shutter 110. Due to the proximity between shutter 110 and FPA 104 in infrared camera 100, the temperature of shutter 110 can be determined based on the measured temperature of FPA 104. In some cases, due to space considerations (e.g., limited space around and / or within the housing, placing a temperature sensor on the component may block the light path to FPA 104, etc.), power considerations (e.g., each set of temperature sensors requires power to operate), and / or other considerations (e.g., equipment cost, maintenance, and / or recalibration, etc.), it may not be possible to place one or more temperature sensors on each component itself.

[0038] Figure 2 A flowchart illustrating an example process 200 for determining SFFC values ​​(e.g., SFFC graphs) according to one or more embodiments of the present disclosure is shown. While this document primarily refers to... Figure 1 The infrared camera 100 describes process 200, but process 200 can also be performed with respect to other systems to determine SFFC values. Please note that... Figure 2 One or more operations can be combined, omitted, and / or performed in different orders as needed.

[0039] In one example Figure 2 Process 200 can be performed by the provider of infrared camera 100 (e.g., manufacturer, designer, and / or other party using infrared camera 100). In this example, the SFFC value can be generated by the provider and stored by infrared camera 100 for subsequent use by the user during operation of infrared camera 100. In another example, in addition to the provider performing process 200, or as an alternative to the provider performing process 200, Figure 2 The process 200 can be performed by the user of the infrared camera 100. In this example, the user can perform calibration (e.g., field calibration) to generate an SFFC value. Such an SFFC value can be considered an updated SFFC value relative to the SFFC value generated by the provider. In yet another example, Figure 2 The execution of process 200 can be distributed between the provider of infrared camera 100 and the user of infrared camera 100.

[0040] At box 205, the infrared camera 100 is powered on. At box 210, one or more temperature sensors 128 monitor temperature characteristics associated with one or more components of the infrared camera 100. By way of non-limiting example, one or more components may include FPA 104, processor 122, memory 124, motor 108, shutter 110, optics block 116 (e.g., one or more optical components of optics block 116), window 170, lens barrel, housing / enclosure, and / or other components of the infrared camera 100. The temperature characteristics associated with the components may include the temperature associated with the components and / or the rate of change of the temperature associated with the components. At box 215, processor 122 determines whether the infrared camera 100 has reached a steady state based on the monitored temperature characteristics. In one aspect, at box 210, one or more temperature sensors 128 may monitor the rate of change of the temperature associated with FPA 104 (e.g., which may be expressed as dT). FPA / dt); and at block 215, processor 122 can determine whether infrared camera 100 has reached steady state based on the rate of temperature change associated with FPA 104. More generally, since different components of infrared camera 100 may reach steady state at different times and at different temperatures, processor 122 can determine at block 215 whether one or more components of infrared camera 100 associated with the SFFC diagram have reached steady state. For illustrative purposes regarding process 200, infrared camera 100 is confirmed / considered to have reached steady state when it is determined that FPA 104 has reached steady state.

[0041] If the processor 122 determines at block 215 that the infrared camera 100 has not yet reached a steady state, the process 200 returns from block 215 to block 210 to continue monitoring the temperature characteristics associated with one or more components (e.g., FPA 104) of the infrared camera 100.

[0042] If processor 122 determines at block 215 that infrared camera 100 has reached a steady state, process 200 proceeds from block 215 to block 220. In this respect, when a steady state is reached, the temperature of one or more components of infrared camera 100 (e.g., FPA 104 and shutter 110, etc.) is at and remains near its respective steady-state temperature. At block 220, FPA 104 captures a first set of images, while shutter 110 does not obstruct FPA 104, and the FOV associated with infrared camera 100 (e.g., the FOV of optical component block 116) is aligned (e.g., covered, overlapped) with a reference object in scene 180 (e.g., also referred to as the scene outside infrared camera 100 or the external scene). The FOV associated with infrared camera 100 may be completely aligned with a reference object. Figure 1In this context, the reference object may be a thermal blackbody 126. The first set of images may include a single image or multiple images (e.g., a sequence of images). In this respect, the FPA 104 can capture images of the reference object(s) outside the infrared camera 100 by receiving electromagnetic radiation (e.g., infrared radiation) associated with the reference object received via optical path 150 and generating one or more images based on that electromagnetic radiation. In some cases, any electromagnetic radiation detected by the FPA 104 may contain non-uniformity associated with shutter 110, the infrared detector of the FPA 104, optics block 116, and / or other components of the infrared camera 100 that may contribute electromagnetic radiation along optical path 150. During block 220, the processing and control block 120 may control the motor 108 so that shutter 110 does not obstruct optical path 150. In one aspect, the reference object may be referred to as an external thermal blackbody or simply an external blackbody, and block 220 may be referred to as an external FFC process or part of an external FFC process.

[0043] In one embodiment, a reference object (e.g., thermal blackbody 126) is at approximately the same steady-state temperature as the shutter 110 when the first set of images of the reference object is captured by the FPA 104. For example, if the shutter 110 is at 30ºC at execution box 220 (e.g., the steady-state temperature of the shutter 110 is 30ºC), the temperature of the reference object is set to 30ºC to track the temperature of the shutter 110. In one aspect, the temperature sensor 128 can measure the temperature of the shutter 110. In another aspect, the temperature sensor 128 can measure the temperature of one or more components in the infrared camera 100 that are relatively close to the shutter 110, and the processor 122 can determine (e.g., estimate) the temperature of the shutter 110 based on the measured temperature of the components(s). Therefore, in some cases, the temperature associated with the shutter 110 can be based on one or more direct temperature measurements of the shutter 110. In some cases, temperature measurements of one or more components (e.g., FPA 104 or lenses of optical element block 116 in some configurations) relatively close to shutter 110 can be used as the temperature of shutter 110, or used to derive (e.g., using relationships) the temperature of shutter 110. In some cases, a relationship (e.g., equations, lookup tables, etc.) between the temperature of shutter 110 and the temperatures of one or more components relatively close to shutter 110 can be determined during the calibration of infrared camera 100. In various embodiments, temperature sensor 128 monitors the temperature of FPA 104, and FPA 104 is close to shutter 110 (e.g., therefore can be considered to be at the same or similar temperature as shutter 110). In such embodiments, due to the proximity between shutter 110 and FPA 104, the temperature associated with shutter 110 can be the temperature of FPA 104, or can be derived from the temperature of FPA 104.

[0044] At frame 225, FPA 104 captures a second set of images while shutter 110 is positioned to block FPA 104, and the field of view (FOV) associated with infrared camera 100 continues to be oriented towards a reference object (e.g., fully oriented). In one embodiment, the reference object is at approximately the same temperature as shutter 110 when FPA 104 captures the second set of images. In this respect, since infrared camera 100 remains in a steady state, the temperatures of the reference object and shutter 110 are approximately at the steady-state temperature of shutter 110. The second set of images may include a single image or multiple images (e.g., a sequence of images). In this respect, FPA 104 can capture one or more images of shutter 110 by receiving electromagnetic radiation via optical path 140 and generating one or more images based on that electromagnetic radiation. In some cases, any electromagnetic radiation detected by FPA 104 may contain non-uniformity associated with shutter 110, the infrared detector of FPA 104, and / or other components of infrared camera 100 that may contribute electromagnetic radiation along optical path 140. During frame 225, processing and control block 120 can control motor 108 to position shutter 110 in optical path 150, causing FPA 104 to capture an image along optical path 140. In one aspect, shutter 110 may be referred to as an internal thermal blackbody or simply an internal blackbody, and frame 225 may be referred to as an internal FFC process or part of an internal FFC process. It should be noted that in some cases, frame 225 may be executed before or after frame 220.

[0045] At box 230, processor 122 determines SFFC values ​​based on the first set of images and the second set of images. SFFC values ​​may be stored (e.g., stored in memory 124 and / or in infrared camera 100 and / or other memory accessible to infrared camera 100) and / or further processed. SFFC values ​​may be provided as an SFFC graph (e.g., stored as an SFFC graph). In this respect, an SFFC graph is a data structure containing SFFC values. SFFC values / graphs may be applied to images. In some aspects, SFFC values ​​may be based on the differences between the first set of images and the second set of images. When the first set of images and / or the second set of images contains multiple images, processor 122 may determine an average of a set of images to obtain an average image. For a given set of images, the value of each pixel in the average image can be obtained by averaging the values ​​of the same pixel in that set of images. For example, when the first set of images and the second set of images contain a first sequence of images and a second sequence of images, respectively, processor 122 may determine the time average of the first sequence and the time average of the second sequence, and subtract the time average of the second sequence from the time average of the first sequence to obtain the differences between the first set of images and the second set of images. In some cases, when determining the average image, one or more pixel values ​​from one or more images in the sequence can be ignored when they are considered outliers (e.g., falling outside the value range) compared to the same pixels in other images.

[0046] In one aspect, the first set of images, or its average, may be, can indicate (e.g., for derivation), and / or can be considered as FFC values ​​associated with optical path 150 (e.g., from external scene 180 to FPA 104), while the second set of images, or its average, may be, can indicate, and / or can be considered as FFC values ​​associated with optical path 140 (e.g., from shutter 110 to FPA 104). Therefore, the difference between the first set of images and the second set of images (e.g., the difference between their averages) may be, can indicate (e.g., for derivation), and / or can be considered as the difference between the FFC values ​​associated with optical path 140 and the FFC values ​​associated with optical path 150. In one aspect, the difference between the first set of images and the second set of images is or indicates the difference between near-zero out-of-field irradiance conditions and steady-state out-of-field irradiance conditions.

[0047] In some embodiments, external FFC operation and capturing the first and second sets of images when the reference object (e.g., a thermal blackbody) is at or near the same temperature as shutter 110 when capturing the corresponding sets of images allow for minimization (e.g., reduction or avoidance) of the in-field signal / component (e.g., the influence of the in-field signal / component) at the steady-state SFFC value compared to conventional methods that perform external and internal FFC when the camera's FOV is covered by a blackbody with ambient room temperature. This is achieved by substantially eliminating the pedestal caused by the in-field signal / component. In this respect, in some aspects, the SFFC value determined according to various embodiments herein can be associated with reduced radiometric measurement errors (e.g., by reducing or eliminating the in-field signal) compared to the SFFC value determined if the reference object of the opposing infrared camera 100 is at ambient room temperature when FPA 104 captures the first and / or second sets of images. Therefore, the SFFC value determined according to various embodiments herein can be a closer representation of only out-of-field signal / component (e.g., substantially no in-field signal / component) at the steady state compared to conventional methods.

[0048] Although Figure 2 The process 200 for determining the SFFC value involves using the shutter 110 as a blackbody (e.g., when performing an internal FFC), but in some embodiments, the SFFC value can be determined without using a shutter or other internal blackbody. Such embodiments can be performed, for example, when the infrared imaging system has no shutter or the shutter is not functioning, and / or when the provider or user does not wish to use a shutter to determine the SFFC value.

[0049] Figure 3 A flowchart illustrating an example process 300 for determining SFFC values ​​(e.g., SFFC plots) without using an internal blackbody, according to one or more embodiments of the present disclosure, is shown. While this document is for illustrative purposes, reference is primarily made to... Figure 1 The infrared camera 100 in the middle is not in use Figure 1 The process 300 is described in the case of shutter 110 shown, but the SFFC value can be determined by performing process 300 on other systems. Please note that Figure 3 One or more operations can be combined, omitted, and / or performed in different orders as needed.

[0050] In one example Figure 3 Process 300 can be performed by the provider of infrared camera 100 (e.g., manufacturer, designer, and / or other party using infrared camera 100). In this example, the SFFC value can be generated by the provider and stored by infrared camera 100 for subsequent use by the user during operation of infrared camera 100. In another example, alternatively, or in addition to the provider performing process 300, Figure 3 The process 300 can be performed by the user of the infrared camera 100. In this example, the user can perform calibration (e.g., field calibration) to generate an SFFC value. Such an SFFC value can be considered an updated SFFC value relative to the SFFC value generated by the provider. In yet another example, Figure 3 The execution of process 300 can be distributed between the provider of infrared camera 100 and the user of infrared camera 100.

[0051] At box 305, infrared camera 100 is powered on. At box 310, FPA 104 captures a first set of images while the field of view (FOV) associated with infrared camera 100 (e.g., the FOV of optical element block 116) is aligned (fully aligned) with a reference object (e.g., thermal blackbody 126) in scene 180. The first set of images may include a single image or multiple images (e.g., a sequence of images). In this respect, FPA 104 can capture images of the reference object(s) outside infrared camera 100 by receiving electromagnetic radiation (e.g., infrared radiation) associated with the reference object received via optical path 150 and generating one or more images based on that electromagnetic radiation.

[0052] FPA 104 can be used to capture the first set of images immediately (e.g., as soon as possible) after the infrared camera 100 is powered on. For example, FPA 104, along with any other components needed to assist or otherwise acquire images, can be used to capture the first set of images once powered on. Typically, when the infrared camera 100 is initially powered on, FPA 104 is at or approximately at room temperature (e.g., also referred to as room temperature or ambient temperature). In this respect, FPA 104 is above the temperature of the environment in which the infrared camera 100 is located (e.g., a room). As an example, room temperature may be between 18ºC and 26ºC. In some cases, FPA 104 may self-heat by about 10ºC or 15ºC upon power-on to reach a steady-state temperature. In such cases, FPA 104 may self-heat from its initial room temperature of about 22ºC to a steady-state temperature between about 32ºC and about 37ºC. In some cases, the infrared camera 100 may be in normal operation before transitioning to calibration operation to perform process 300 (e.g., for capturing images not used for calibration purposes). In some cases, the infrared camera 100 may have been turned off for a sufficient amount of time before block 305 of process 300 to allow the FPA 104 to reach approximately room temperature.

[0053] In one embodiment, the reference object (e.g., thermal blackbody 126) is at room temperature, and thus may be referred to as a room environment thermal blackbody. In this respect, at block 310, both the reference object and FPA 104 are approximately at room temperature. In some cases, the temperature of the reference object is not controlled, and the reference object is at room temperature simply because it exists in an environment at room temperature (e.g., a room). In other cases, the temperature of the reference object is controlled (e.g., using appropriate heating elements(one or more) and / or cooling elements(one or more)) to set the temperature of the reference object to room temperature.

[0054] At block 315, one or more temperature sensors 128 monitor temperature characteristics associated with one or more components of the infrared camera 100. The temperature characteristics associated with the components may include the temperature associated with the component and / or the rate of change of the temperature associated with the component. At block 320, processor 122 determines whether the infrared camera 100 has reached a steady state based on the monitored temperature characteristics. In one aspect, at block 315, the one or more temperature sensors 128 may monitor the rate of change of temperature associated with the FPA 104 (e.g., which may be expressed as dT). FPA At block 320, processor 122 can determine whether infrared camera 100 has reached steady state based on the rate of temperature change associated with FPA 104. Since different components of infrared camera 100 may reach steady state at different times and temperatures, processor 122 can determine at block 320 whether one or more components of infrared camera 100 associated with the SFFC diagram have reached steady state. For illustrative purposes regarding process 300, infrared camera 100 is considered to have reached steady state when it is determined that FPA 104 has reached steady state.

[0055] If the processor 122 determines at block 320 that the infrared camera 100 has not yet reached a steady state, the process 300 returns from block 320 to block 315 to continue monitoring the temperature characteristics associated with one or more components (e.g., FPA 104) of the infrared camera 100.

[0056] If the processor 122 determines at block 320 that the infrared camera 100 has reached a steady state, process 300 proceeds from block 320 to block 325. In this respect, when a steady state has been reached, one or more components of the infrared camera 100 (e.g., FPA 104, etc.) are at their respective steady-state temperatures and remain approximately at their respective steady-state temperatures. At block 325, the FPA 104 captures a second set of images, while the field of view associated with the infrared camera 100 is oriented (e.g., fully oriented) towards a reference object at a temperature approximately the same as the temperature of the FPA 104 at the time the second set of images is captured. The second set of images may comprise a single image or multiple images (e.g., a sequence of images). In this respect, the FPA 104 can capture one or more images of a thermal blackbody by receiving electromagnetic radiation via optical path 150 and generating one or more images based on that electromagnetic radiation.

[0057] In some respects, the reference object used at frame 325 is the same as the reference object used at frame 310. When the same reference object is used at frames 310 and 325, the reference object can be heated to track the heat generation (e.g., self-heating) of FPA 104, such that the temperature change of FPA 104 between frames 310 and 325 (e.g., FPA 104 warming from room temperature to steady-state temperature) is the same as or similar to the temperature change of the reference object between frames 310 and 325. In other respects, the reference object used at frame 325 is different from the reference object used at frame 310. In such respects, when capturing the second set of images, the temperature of the reference object used at frame 325 is set to the temperature of FPA 104, while when capturing the first set of images, the reference object used at frame 310 is at approximately room temperature.

[0058] At box 330, processor 122 determines SFFC values ​​based on the first set of images and the second set of images. SFFC values ​​may be stored (e.g., stored in memory 124 and / or in infrared camera 100 and / or other memory accessible to infrared camera 100) and / or further processed. SFFC values ​​may be provided as SFFC maps (e.g., stored as SFFC maps). In some aspects, SFFC values ​​may be based on the differences between the first set of images and the second set of images. When the first set of images and / or the second set of images contains multiple images, processor 122 may determine an average of the set of images to obtain an average image. For a given set of images, the value of each pixel in the average image can be obtained by averaging the values ​​of the same pixel in that set of images. For example, when the first set of images and the second set of images contain a first sequence of images and a second sequence of images, respectively, processor 122 may determine the time average of the first sequence and the time average of the second sequence, and subtract the time average of the second sequence from the time average of the first sequence to obtain the difference between the first set of images and the second set of images. In some cases, when determining the average image, a pixel value(s) in one or more images of a sequence may be ignored if it is considered an outlier (e.g., falling outside the value range) compared to the same pixel in other images. In one aspect, the difference between the first set of images and the second set of images is, or indicates, the difference between near-zero off-field irradiance conditions and steady-state off-field irradiance conditions.

[0059] In some embodiments, capturing a second set of images when the reference object (e.g., a thermal blackbody) is at or near the same temperature as FPA 104 allows for minimization (e.g., reduction or avoidance) of the in-field signal / component (e.g., the influence of the in-field signal / component) at the steady-state SFFC value compared to conventional methods that capture images of a blackbody at room temperature after the camera has reached steady state (e.g., by substantially eliminating the base caused by the in-field signal / component). In this respect, in some aspects, the SFFC value determined according to the various embodiments herein can be associated with reduced radiometric measurement errors (e.g., by reducing or eliminating the in-field signal) relative to the SFFC value determined if the reference object of the opposing infrared camera 100 is at room temperature when FPA 104 captures the second set of images. Therefore, the SFFC value determined according to the various embodiments herein can be a closer representation of only out-of-field signals / components (e.g., substantially no in-field signals / components) at steady state compared to conventional methods.

[0060] SFFC values ​​(e.g., SFFC values ​​determined by execution process 200 or 300) can be provided (e.g., stored) as an SFFC graph. In this respect, an SFFC graph is a data structure containing SFFC values. SFFC values / graphs can be applied to images. SFFC values ​​can be, can be assumed, and / or can be derived from the differences between a first set of images and a second set of images. In some cases, the differences can be processed to obtain SFFC values. As an example, processor 122 can optionally apply smoothing to the differences (e.g., to minimize high-frequency noise in previously acquired image data). Such smoothing can utilize kernel smoothing techniques, high-frequency noise suppression techniques, pixel value blurring techniques, and / or other suitable techniques known to those skilled in the art. For example, kernel smoothing can be applied using any desired density and / or any desired number of repetitions. In some cases, processor 122 can scale the difference values ​​or smoothed differences to correspond to -2. N +1 to +2 N The SFFC value is obtained by scaling to an N-bit resolution within a range between -127 and 128 (e.g., for storage, application to image data, and / or further processing). As an example, an SFFC value scaled to 8-bit resolution can be in the range between -127 and 128 (e.g., using 7 data bits and 1 sign bit), while an SFFC value scaled to 15-bit resolution can be in the range between -16383 and 16384 (e.g., using 14 data bits and 1 sign bit). The value of N can be chosen depending on the application to allow efficient use of memory during processing (e.g., memory 124) while providing sufficient resolution to mitigate potential non-uniformity in the image data captured by the FPA 104. In some cases, instead of processing the difference between the first and second sets of images, such processing can be performed on both sets, and then the difference between the processed first and second sets of images can be determined to determine the SFFC value.

[0061] In some embodiments, different sets of SFFC values ​​may be determined and stored. Calibration may be performed by the manufacturer of the infrared camera 100 (e.g., factory calibration) or by the user (e.g., field calibration) to determine one or more sets of SFFC values. Each set of SFFC values ​​may be associated with different configurations of the infrared camera 100, such as different optical blocks in the optical path 150 (e.g., the arrangement of one or more optical elements), housings / enclosures, mounting hardware, and / or other components of the infrared camera 100. For example, if a user replaces the lens of optical block 116 with another lens, the user may perform calibration on the infrared camera 100 to determine a new / updated set of SFFC values. A new set of SFFC values ​​associated with a new / current configuration of optical block 116 may overwrite a previous set of SFFC values ​​associated with a previous configuration of optical block 116, or may be stored separately from a previous set of SFFC values ​​(e.g., a previous set of SFFC values ​​may continue to be stored and retrieved, for example, if the current configuration of optical block 116 is restored to a previous configuration).

[0062] The SFFC values ​​determined at boxes 230 and / or 330 can be applied to subsequent images captured by the FPA 104 (e.g., images captured not for calibration purposes to determine SFFC values). In some cases, the SFFC values ​​can be further processed before being applied to the image. As an example, as further described herein, a scaling factor (e.g., also referred to as a scaling term) (e.g., determined by processor 122) can be determined and applied to the SFFC values ​​to obtain a set of scaled SFFC values. This set of scaled SFFC values ​​can be applied to the image (e.g., applied by processor 122). In some cases, the scaling factor can be based on captured image data, such as the temperature and / or temperature changes over time of one or more objects in the scene. Since the SFFC map determined according to embodiments herein may have substantially no in-field signal / component, and therefore substantially no base due to in-field signal / component, the base is not scaled when the SFFC map is scaled during real-time operation. Scaled SFFC maps with bases complicate radiometric processing. U.S. Patent No. 10,986,288 and U.S. Patent Application Publication No. 2022 / 0261964 provide examples of systems and methods for determining scaling factors that can be applied to SFFC values ​​(such as SFFC values ​​generated according to various embodiments herein), the entire contents of which are incorporated herein by reference.

[0063] Figure 4 A flowchart illustrating an example process 400 for applying SFFC values ​​to captured image data according to one or more embodiments of the present disclosure is shown. While this document is for illustrative purposes, reference is primarily made to... Figure 1The infrared camera 100 described in process 400 can be used to apply SFFC values ​​by performing process 300 on other systems. Please note that Figure 4 One or more operations can be combined, omitted, and / or performed in different orders as needed.

[0064] At block 405, processor 122 determines a scaling factor / item to be applied to the SFFC graph (e.g., the SFFC values ​​of the SFFC graph). Processor 122 may retrieve the SFFC graph from memory 124, other internal memory of infrared camera 100, and / or external memory of infrared camera 100. In some embodiments, the SFFC graph may be generated by executing process 200 or 300. In some cases, the scaling factor may be adjusted / updated in real-time or near real-time, periodically, and / or upon user request. In some cases, the scaling factor may be adjusted / updated in real-time or near real-time in response to changes in temperature and / or rate of temperature change (e.g., measured by one or more temperature sensors) of one or more components of infrared camera 100 (e.g., FPA 104).

[0065] At block 410, processor 122 applies a scaling factor to the SFFC map to obtain a scaled SFFC map. At block 415, processor 122 applies the scaled SFFC map to the thermal image data. The thermal image data may be a thermal image captured by FPA 104, or it may be a processed version of a thermal image captured by FPA 104. Processor 122 may apply the scaled SFFC map to the thermal image data in real time as FPA 104 captures the thermal image data, or it may be applied to thermal image data associated with a thermal image previously captured by FPA 104 and stored for subsequent acquisition / processing. It should be noted that in some applications, the scaling factor is not determined / applied. In this regard, referring to process 400, the scaling factor may be considered to be set to 1, such that the SFFC map (e.g., determined by process 200, process 300, or other processes) is applied directly to the thermal image data.

[0066] In some embodiments, a user interface may be presented to an operator (e.g., a manufacturer and / or a user) to facilitate the calibration of the infrared camera 100 (e.g., to determine SFFC values). In some cases, the user interface may provide prompts or instructions to the operator to perform calibration on the infrared camera 100. As an example, Figure 5 An example display screen 500 is shown, on which a dialog box 505 is displayed to facilitate calibration of the infrared camera 100 according to one or more embodiments of this disclosure. The display screen 500 may be provided by a display device integrated as part of the infrared camera 100 and / or a display device separate from but communicatively connected to the infrared camera 100. Figure 5As shown, dialog box 505 provides text indicating the reason for suggesting calibration and asking the user whether they wish to begin calibration by interacting with interface element 510 (i.e., the "Calibrate Now" button) or wait until a later time by interacting with interface element 515 (i.e., the "Remind Me Later" button) (e.g., the user can set a reminder time). Other non-limiting examples of reasons for suggesting calibration may include: the amount of time since the last calibration exceeds a threshold time (e.g., set by the manufacturer or user); changes in the operating conditions of infrared camera 100 (e.g., ambient temperature); and / or user changes functional parameters (e.g., changing the frame rate or gain mode). Display screen 500 may allow user input (e.g., interaction with dialog box 505) via mouse (e.g., user input including mouse movement and mouse click), keyboard input, and / or touch input interacting with interface elements 510 and 515.

[0067] While dialog box 505 provides the user with the option to perform calibration at a later time, in some applications, such as those requiring constant minimization of radiometric measurement errors, and / or other applications where the use of infrared camera 100 is not permitted when previous calibration results may be outdated, calibration may be necessary before infrared camera 100 can be used to capture images in normal operation. The user may be provided with an option to indicate when infrared camera 100 should begin calibration, or a countdown (e.g., a few seconds) may be provided before infrared camera 100 automatically begins calibration (unless manually postponed by the user). In some cases, as an alternative to a display with a graphical user interface window, or in addition, infrared camera 100 may have indicator lights (e.g., flashing light-emitting diodes (LEDs)) to indicate when calibration is recommended or required (e.g., before infrared camera 100 can be used to capture images in normal operation).

[0068] In some cases, the user interface can provide users with an overview, instructions, and / or guidance to facilitate calibration. As an example, Figure 6 A display screen 500 is shown, on which a dialog box 605 is displayed to facilitate calibration of the infrared camera 100 according to one or more embodiments of the present disclosure. The display screen 500 may be provided by a display device integrated as part of the infrared camera 100 and / or a display device separate from but communicatively connected to the infrared camera 100. In one case, when interface element 510 (i.e., the "Calibrate Now" button) in the dialog box 505 is selected, the display screen 500 can be accessed from... Figure 5 The dialog box 505 has been changed to Figure 6 Dialog box 605. As shown in dialog box 605, it provides the user with an overview of the steps associated with calibration. Different sections of the calibration overview can be scrolled up and down using slider 610, navigation buttons 615 and 620, swipe gestures, keyboard input, and / or other means.

[0069] As an alternative to or in addition to the overview displayed in dialog box 600, display screen 500 may show the user one step at a time and request the user's confirmation that the step has been performed before proceeding to the next step. For example, display screen 500 may instruct the user to "set the temperature of the reference object to the FPA temperature" and provide a button for user interaction to indicate this after the user has completed setting the reference object to the FPA temperature. After the user provides confirmation that the reference object has been set to the FPA temperature, display screen 500 may proceed to the next step to instruct the user on the location of the reference object and provide a button for user interaction to indicate this after the user has completed placing the reference object. After the user provides confirmation that the reference object has been correctly placed, display screen 500 may proceed to the next step to instruct the user that the infrared camera 100 will capture images and provide a button for user interaction to cause the infrared camera 100 to begin capturing images (e.g., a predetermined number of images set by the manufacturer or user).

[0070] Therefore, using various embodiments, an infrared imaging system (e.g., infrared camera 100) can be calibrated and calibrated by itself to generate SFFC values ​​(e.g., SFFC maps) that minimize the in-field signal / component, which is essentially entirely represented by the out-of-field irradiance at steady state. When calibration is performed using an internal reference object / structure (e.g., shutter lever), for example in process 200, the in-field signal / component can be reduced or avoided by performing an external FFC operation and acquiring a set of images of the reference object at approximately the same temperature as the internal structure under steady-state conditions. Without using a shutter or other internal structure, for example in process 300, the in-field signal / component can be reduced or avoided by acquiring a set of images of the reference object after steady state has been reached, at approximately the same temperature as the FPA at the time of image acquisition. Using such methods reduces or avoids the signal caused by the in-field irradiance from the scene, thereby essentially eliminating the base caused by the in-field signal / component and providing an SFFC map as a closer representation of only the out-of-field signal / component at steady state. The SFFC values ​​generated according to various embodiments can better reduce or eliminate radiometric measurement errors, such as those caused by off-field irradiance, thereby mitigating the non-uniformity caused by off-field irradiance. When the SFFC map is scaled during real-time operation, the substrate is not scaled. If such a substrate is not eliminated or at least not reduced, it will complicate the radiometric measurement process.

[0071] Figure 7A block diagram of an example imaging system 700 according to one or more embodiments of the present disclosure is shown. However, not all components shown are essential, and one or more embodiments may include other components not shown in the figures. Changes may be made to the arrangement and type of components without departing from the spirit or scope set forth in the claims herein. Additional components, different components, and / or fewer components may be provided. In one embodiment, the imaging system 700 may be Figure 1 Infrared camera 100, may include Figure 1 Infrared camera 100 or can be Figure 1 It is part of the infrared camera 100.

[0072] According to one embodiment of this disclosure, imaging system 700 can be used to capture and process images. Imaging system 700 can represent any type of imaging system that detects one or more ranges (e.g., bands) of EM radiation and provides representative data (e.g., one or more still image frames or video image frames). Imaging system 700 may include imaging device 705. By way of non-limiting example, imaging device 705 may be, can include, an infrared camera (e.g., a thermal infrared camera), a visible light camera, a tablet computer, a laptop computer, a personal digital assistant (PDA), a mobile device, a desktop computer, or other electronic device, or may be part of such devices. Imaging device 705 may include a housing (e.g., a camera body) that at least partially surrounds the components of imaging device 705, for example, to promote the compactness and protection of imaging device 705. Figure 7 The solid-line frame marked 705 represents the housing of the imaging device 705. This housing may include components that are larger than... Figure 7 The solid lines within the image show more, fewer, and / or different components of the imaging device 705. In one embodiment, the imaging system 700 may include a portable device and may be incorporated, for example, into a vehicle or a non-mobile device that needs to store and / or display images. The vehicle may be a land-based vehicle (e.g., a car, truck), a sea-based vehicle, an air vehicle (e.g., an unmanned aerial vehicle (UAV)), a space vehicle, or generally any type of vehicle in which the imaging system 700 can be integrated (e.g., mounted within, on, etc.). In another example, the imaging system 700 may be coupled to various types of fixed locations (e.g., home security mounts, campsite or outdoor mounts, or other locations) via one or more types of mounts.

[0073] According to one embodiment, imaging device 705 includes logic device 710 (e.g., also referred to as processing unit), memory unit 715, image capture unit 720 (e.g., imager, image sensor device), image interface 725, control unit 730, display unit 735, sensing unit 740, and / or network interface 745. According to various embodiments, logic device 710 includes one or more of the following: processor, microprocessor, central processing unit (CPU), graphics processing unit (GPU), single-core processor, multi-core processor, microcontroller, programmable logic device (PLD) (e.g., field-programmable gate array (FPGA)), application-specific integrated circuit (ASIC), digital signal processing (DSP) device, or other logic device; one or more memories for storing executable instructions (e.g., software, firmware, or other instructions); and / or any other suitable combination of processing device and / or memory for executing instructions to perform any of the various operations described herein. Logic device 710 can be configured to perform the various operations discussed herein with respect to embodiments of this disclosure by hard-wiring, executing software instructions, or a combination of both. Logic device 710 may be configured to connect and communicate with various other components of imaging system 700 (e.g., 715, 720, 725, 730, 735, 740, 745, etc.) to perform operations such as those described above. For example, logic device 710 may be configured to process captured image data received from imaging capture unit 720, store image data in memory unit 715, and / or retrieve stored image data from memory unit 715. In one aspect, logic device 710 may be configured to perform various system control operations (e.g., to control the communication and operation of various components of imaging system 700), calibration operations (e.g., processes 200 and / or 300), and other image processing operations (e.g., process 400, de-Bayering, sharpening, color correction, offset correction, data conversion, data transformation, data compression, video analysis, etc.). In one embodiment, logic device 710 may be, may include, or may be part of processor 122.

[0074] In one embodiment, memory component 715 includes one or more memory devices configured to store data and information, including infrared image data and information. Memory component 715 may include one or more different types of memory devices, including volatile and non-volatile memory devices, such as random access memory (RAM), dynamic random access memory (DRAM), static RAM (SRAM), non-volatile random access memory (NVRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, hard disk drive, and / or other types of memory. As described above, logic device 710 may be configured to execute software instructions stored in memory component 715 to perform method and process steps and / or operations. Logic device 710 and / or image interface 725 may be configured to store image or digital image data captured by image capture component 720 in memory component 715. In one or more embodiments, such instructions, when executed by logic device 710, cause imaging system 700 to perform operations to generate SFFC values ​​(e.g., procedures 200 and / or 300) and apply SFFC values ​​(e.g., procedure 400). In some embodiments, memory component 715 may store various SFFC values ​​from factory calibration and / or runtime / field calibration. In one embodiment, memory component 715 may be, may include, or may be a portion of memory 124.

[0075] In some embodiments, a separate machine-readable medium 750 (e.g., memory, such as a hard disk drive, compact disk, digital video optical disc, or flash memory) may store software instructions and / or configuration data that a computer (e.g., a logic device or processor-based system) can execute or access to perform various methods and operations, such as those related to processing image data. In one aspect, the machine-readable medium 750 may be portable and / or located separately from the imaging device 705, wherein the stored software instructions and / or data are provided to the imaging device 705 by coupling the machine-readable medium 750 to the imaging device 705, and / or by downloading from the machine-readable medium 750 to the imaging device 705 via (e.g., via a wired link and / or a wireless link). It should be understood that various modules may be integrated into the software and / or hardware as part of the logic device 710, wherein code for the module (e.g., software or configuration data) is stored, for example, in a memory component 715.

[0076] Imaging device 705 may be a video and / or still camera that captures and processes images and / or videos of scene 775. In this regard, image capture component 720 of imaging device 705 may be configured to capture images (e.g., still images and / or video images) of scene 775 in a specific spectrum or mode. In one embodiment, image capture component 720 may be, may include, or may be part of FPA 104. Image capture component 720 includes image detector circuitry 765 (e.g., visible light detector circuitry, thermal infrared detector circuitry) and readout circuitry 770 (e.g., ROIC). For example, image capture component 720 may include an IR imaging sensor (e.g., an IR imaging sensor array) configured to detect IR radiation in the near-infrared, mid-infrared, and / or far-infrared spectra and provide an IR image (e.g., IR image data or signal) representing the IR radiation from scene 775. For example, image detector circuitry 765 may capture (e.g., detect, sense) IR radiation in a wavelength range from about 700 nm to about 2 mm or a portion thereof. For example, in some aspects, the image detector circuit 765 may be sensitive to SWIR radiation, mid-wave IR (MWIR) radiation (e.g., EM radiation with wavelengths from 2µm to 5µm), and / or long-wave IR (LWIR) radiation (e.g., EM radiation with wavelengths from 7µm to 14µm), or to any desired IR wavelength (e.g., typically in the range of 0.7µm to 14µm) (e.g., for better detection). In other aspects, the image detector circuit 765 may capture radiation from one or more other bands in the EM spectrum, such as visible light, ultraviolet light, etc.

[0077] Image detector circuit 765 can capture image data (e.g., infrared image data) associated with scene 775. To capture an image, image detector circuit 765 can detect image data (e.g., in the form of EM radiation) of scene 775 received through aperture 780 of imaging device 705 and generate pixel values ​​for the image based on scene 775. The image can be referred to as a frame or image frame. In some cases, image detector circuit 765 may include a detector array (e.g., also referred to as a pixel array) that can detect radiation in a specific band, convert the detected radiation into electrical signals (e.g., voltage, current, etc.), and generate pixel values ​​based on the electrical signals. Each detector in the array can capture a corresponding portion of the image data and generate pixel values ​​based on the corresponding portion captured by the detector. The pixel values ​​generated by the detector can be referred to as the detector output. By way of non-limiting example, each detector can be a photodetector, such as an avalanche photodiode, an infrared photodetector, a quantum well infrared photodetector, a microbolometer, or other detector capable of converting EM radiation (e.g., EM radiation at a specific wavelength) into pixel values. The detector array can be arranged in rows and columns.

[0078] An image can be, or can be considered, a data structure containing pixels and a representation of image data associated with scene 775, wherein each pixel has a pixel value representing EM radiation emitted or reflected from a portion of scene 775 and received by a detector that generates the pixel value. Depending on the context, a pixel can refer to a detector in image detector circuit 765 that generates the associated pixel value, or it can refer to a pixel in the image formed by the generated pixel values ​​(e.g., pixel location, pixel coordinates). In one embodiment, the image can be a thermal infrared image (e.g., also called a thermal image) based on thermal infrared image data. Each pixel value of the thermal infrared image represents the temperature of the corresponding portion of scene 775.

[0079] In one aspect, the pixel value generated by the image detector circuit 765 can be represented as a digital count value generated based on an electrical signal obtained from the radiation detected by the conversion. For example, where the image detector circuit 765 includes or is otherwise coupled to an ADC circuit, the ADC circuit can generate a digital count value based on the electrical signal. For an ADC circuit capable of using 14 bits to represent the electrical signal, the range of the digital count value can be from 0 to 16383. In such a case, the pixel value of the detector can be a digital count value output from the ADC circuit. In other cases (e.g., in the absence of an ADC circuit), the pixel value can be essentially analog, with a value equal to or indicating the value of the electrical signal. As an example, for infrared imaging, a larger amount of infrared radiation incident on and detected by the image detector circuit 765 (e.g., an IR image detector circuit) is associated with a higher digital count value and a higher temperature.

[0080] The readout circuit 770 serves as an interface between the image detector circuit 765, which detects image data, and the logic device 710, which processes the detected image data read out by the readout circuit 770. The image interface 725 facilitates the transfer of data from the readout circuit 770 to the logic device 710. The image capture frame rate can refer to the rate at which images are sequentially detected / output by the image detector circuit 765 and provided to the logic device 710 by the readout circuit 770 (e.g., images output per second by the detector). The readout circuit 770 can read out the pixel values ​​generated by the image detector circuit 765 according to the integration time (e.g., also referred to as the integration period).

[0081] In various embodiments, the combination of image detector circuitry 765 and readout circuitry 770 may be, may include, or may be provided together as an FPA (e.g., FPA 104). In some aspects, image detector circuitry 765 may be a thermal image detector circuit comprising a microbolometer array, and the combination of image detector circuitry 765 and readout circuitry 770 may be referred to as a microbolometer FPA. In some cases, the microbolometer array may be arranged in rows and columns. The microbolometers may detect IR radiation and generate pixel values ​​based on the detected IR radiation. For example, in some cases, the microbolometer may be a thermal IR detector that detects IR radiation in the form of thermal energy and generates pixel values ​​based on the amount of detected thermal energy. The microbolometers may absorb incident IR radiation and generate a corresponding temperature change within the microbolometer. The temperature change is associated with a corresponding change in the resistance of the microbolometer. Each microbolometer serves as a pixel, and a two-dimensional image or picture representation of the incident IR radiation can be generated by converting the resistance change of each microbolometer into a time-division multiplexed electrical signal. This conversion may be performed by a ROIC. Microbolometers (FPAs) may include IR detection materials such as amorphous silicon (a-Si) and vanadium oxide (VO₂O₃). x ( ), combinations thereof, and / or (one or more) other detection materials. In one aspect, for a microbolometer FPA, the integration time can be or may indicate the time interval during which the microbolometer is biased. In this case, a longer integration time may be associated with a higher IR signal gain, but without collecting more IR radiation. IR radiation can be collected by the microbolometer in the form of thermal energy.

[0082] In some cases, the image capture component 720 may include one or more optical components and / or one or more filters. The optical components may include one or more windows, lenses, mirrors, beam splitters, beam couplers, and / or other components that guide and / or focus radiation to the image detector circuitry 765. The optical components may include components formed from various materials and appropriately arranged according to desired transmission characteristics (e.g., desired transmission wavelengths and / or light transmission matrix characteristics). The filters may be adapted to allow radiation of certain wavelengths to pass through while substantially blocking radiation of other wavelengths. For example, the image capture component 720 may be an IR imaging device that includes one or more filters adapted to allow IR radiation of certain wavelengths to pass through while substantially blocking IR radiation of other wavelengths (e.g., MWIR filters, thermal IR filters, and narrowband filters). In this example, such filters can be used to customize the image capture component 720 to increase sensitivity to desired bands of IR wavelengths. In one aspect, when an IR imaging device is customized for capturing thermal IR images, it may be referred to as a thermal imaging device. Other imaging devices, including IR imaging devices customized for capturing infrared IR images outside the thermal range, may be referred to as non-thermal imaging devices. In one embodiment, one or more optical components and, in some cases, one or more filters may form an optical device block 116 or a portion thereof.

[0083] In one particular non-limiting example, the image capture component 720 may include an IR imaging sensor having an FPA that detects IR radiation including near-infrared (NIR), SWIR, MWIR, LWIR, and / or very long wave IR (VLWIR) radiation. In other embodiments, alternatively or additionally, the image capture component 720 may include a complementary metal-oxide-semiconductor (CMOS) sensor or a charge-coupled device (CCD) sensor, which can be found in any consumer-grade camera (e.g., a visible light camera).

[0084] In some embodiments, the imaging system 700 includes a shutter 785. The shutter 785 is operable to selectively insert itself into the optical path between the scene 775 and the image capture component 720, thereby exposing or blocking the aperture 780. While the shutter 785 is shown as an internal shutter (e.g., a shutter within the housing of the imaging device 705), the shutter 785 may also be located externally to the housing. In some cases, the shutter 785 may be movable either inside or outside the housing. In other cases, the shutter 785 is designed to be located only inside or only outside the housing. In some cases, the shutter 785 may be manually moved (e.g., sliding, rotating, etc.) (e.g., manually moved by a user of the imaging system 700) and / or moved by an actuator (e.g., by logic device 710 in response to user input or autonomously controllable, e.g., logic device 710 autonomously decides to perform calibration on the imaging device 705).

[0085] When shutter 785 is outside the optical path exposing aperture 780, electromagnetic radiation from scene 775 can be received by image detector circuit 765 (e.g., through one or more optical components and / or one or more filters). Therefore, image detector circuit 765 captures an image of scene 775. Shutter 785 may be referred to as being in the open position, or simply as open. When shutter 785 is inserted into the optical path to block aperture 780, electromagnetic radiation from scene 775 is blocked and cannot reach image detector circuit 765. Therefore, image detector circuit 765 captures an image of shutter 785. Shutter 785 may be referred to as being in the closed position, or simply as closed. In some cases, shutter 785 can block aperture 780 during calibration, where shutter 785 can be used as a uniform blackbody (e.g., a substantially uniform blackbody). For example, in some cases, the surface of shutter 785 imaged by image detector circuit 765 can be achieved through a uniform blackbody coating. In some cases, such as for imaging devices without a shutter or with a damaged shutter, or as an alternative to shutter 785, a housing or sleeve of imaging device 705, a lens cover, a shroud, a room wall, or other suitable object / surface can be used to provide a uniform blackbody (e.g., a substantially uniform blackbody). In one embodiment, shutter 785 may be shutter 110.

[0086] Other imaging sensors that may be included in the image capture unit 720 include photon mixer device (PMD) imaging sensors or other time-of-flight (ToF) imaging sensors, LiDAR imaging devices, RADAR imaging devices, millimeter-scale imaging devices, positron emission tomography (PET) scanners, single-photon emission computed tomography (SPECT) scanners, ultrasound imaging devices, or other imaging devices that operate in a specific modality and / or spectrum. It should be noted that some of these imaging sensors configured to capture images in a specific modality and / or spectrum (e.g., infrared spectroscopy, etc.) are more likely to produce images with low-frequency shadows compared to general CMOS-based or CCD-based imaging sensors or other imaging sensors, imaging scanners, or imaging devices of different modalities.

[0087] The image or corresponding digital image data provided by the image capture unit 720 can be associated with a corresponding image size (also known as pixel size). Image size or pixel size typically refers to the number of pixels in an image; for example, for a two-dimensional image, it can be represented by width multiplied by height, or in other ways appropriate for the relevant size or image shape. Therefore, an image size with its native resolution can be resized to a smaller size (e.g., with a smaller pixel size) to, for example, reduce the cost of processing and analyzing the image. Filters (e.g., non-uniformity estimations) can be generated based on the analysis of the resized image. The filter size can then be resized to the image's native resolution and size before being applied to the image.

[0088] In some embodiments, the image interface 725 may include suitable input ports, connectors, switches, and / or circuitry configured to connect to an external device (e.g., remote device 755 and / or other devices) to receive images (e.g., digital image data) generated at or otherwise stored at the external device. In one aspect, the image interface 725 may include a serial interface and telemetry lines for providing metadata associated with the image data. The received image or image data may be provided to the logic device 710. In this respect, the received image or image data may be converted into signals or data suitable for processing by the logic device 710. For example, in one embodiment, the image interface 725 may be configured to receive analog video data and convert it into suitable digital data for provision to the logic device 710.

[0089] The image interface 725 may include various standard video ports that can be connected to a video player, camera, or other device capable of generating standard video signals, and can convert received video signals into digital video / image data suitable for processing by the logic device 710. In some embodiments, the image interface 725 may also be configured to connect to and receive images (e.g., image data) from the image capture unit 720. In other embodiments, the image capture unit 720 may be directly connected to the logic device 710.

[0090] In one embodiment, control unit 730 includes user input and / or interface devices, such as rotary knobs (e.g., potentiometers), buttons, sliders, keyboards, and / or other devices adapted to generate user input control signals. Logic device 710 is configured to detect control input signals from the user through control unit 730 and respond to any detected control input signals received therefrom. Logic device 710 is configured to interpret such control input signals as values ​​generally understood by those skilled in the art. In one embodiment, control unit 730 may include a control unit (e.g., a wired or wireless handheld control unit) having buttons adapted to interact with the user and receive user input control values. In one embodiment, the buttons and / or other input mechanisms of the control unit can be used to control various functions of imaging device 705, such as calibration initiation and / or related control, shutter control, autofocus, menu activation and selection, field of view, brightness, contrast, noise filtering, image enhancement, and / or other various functions.

[0091] In one embodiment, display component 735 includes an image display device (e.g., a liquid crystal display (LCD)) or various other types of generally known video displays or monitors. Logic device 710 is configured to display image data and information on display component 735. Logic device 710 is configured to acquire image data and information from memory component 715 and display any acquired image data and information on display component 735. Display component 735 may include display circuitry that logic device 710 can utilize to display image data and information. Display component 735 may be adapted to receive image data and information directly from image capture component 720, logic device 710, and / or image interface 725, or image data and information may be transferred from memory component 715 via logic device 710. In some cases, a user interface may be presented through display component 735 to facilitate calibration of imaging system 700 (e.g., one or more components of imaging system 700). In some aspects, control component 730 may be implemented as part of display component 735. For example, the touchscreen of the imaging device 705 can provide a control unit 730 (e.g., for receiving user input via clicks and / or other gestures) and a display unit 735 for the imaging device 705. In one embodiment, Figure 5 and Figure 6 The display screen 500 can be implemented by the display component 735, and / or the interaction with the display screen 500 can be implemented by the control component 730.

[0092] In one embodiment, sensing component 740 includes one or more sensors of various types, the specific type depending on application or implementation requirements, as understood by those skilled in the art. The sensors of sensing component 740 provide data and / or information to at least logic device 710. In one aspect, logic device 710 may be configured to communicate with sensing component 740. In various embodiments, sensing component 740 may provide information about environmental conditions, such as external temperature, lighting conditions (e.g., daytime, nighttime, dusk, and / or dawn), humidity levels, specific weather conditions (e.g., sunny, rainy, and / or snowy), distance (e.g., laser rangefinder or time-of-flight camera), and / or whether one has entered or exited a tunnel or other type of enclosed space. Sensing component 740 may represent conventional sensors commonly known to those skilled in the art, used to monitor various conditions (e.g., environmental conditions) that may affect (e.g., affect the appearance of the image) provided by image capture component 720.

[0093] In some implementations, sensing component 740 (e.g., one or more sensors) may include a device that transmits information to logic device 710 via wired and / or wireless communication. For example, sensing component 740 may be adapted to receive information from satellites, via local broadcast (e.g., radio frequency (RF)) transmission, via mobile or cellular networks and / or via information beacons in infrastructure (e.g., traffic or highway information beacon infrastructure), or via various other wired and / or wireless technologies. In some embodiments, logic device 710 may use information acquired from sensing component 740 (e.g., sensing data) to modify the configuration of image capture component 720 (e.g., adjust the light sensitivity level, adjust the orientation or angle of image capture component 720, adjust the aperture, etc.).

[0094] In one embodiment, the sensing component 740 may be or may include Figure 1 The imaging device 705 may include one or more temperature sensors 128. The sensing component 740 may include a temperature sensing component to provide temperature data (e.g., one or more measured temperature values) of various components of the imaging device 705 (e.g., image detector circuitry 765 and / or shutter 785). By way of non-limiting example, the temperature sensor may include a thermistor, thermocouple, thermopile, pyrometer, and / or other suitable sensors for providing temperature data.

[0095] In some embodiments, various components of the imaging system 700 may be distributed on and communicate with each other via a network 760. In this regard, the imaging device 705 may include a network interface 745 configured to facilitate wired and / or wireless communication between the various components of the imaging system 700 via the network 760. In such embodiments, components may be duplicated if required for a specific application of the imaging system 700. That is, components configured for the same or similar operations may be distributed on the network. Furthermore, if desired, all or part of any of the various components may be implemented using appropriate components of a remote device 755 (e.g., a conventional digital video recorder (DVR), a computer configured for image processing, and / or other devices) that communicates with the various components of the imaging system 700 via the network interface 745 through the network 760. Thus, for example, all or part of the logic device 710, all or part of the memory component 715, and / or all or part of the display component 735 may be implemented or duplicated at the remote device 755. In some embodiments, the imaging system 700 may not include an imaging sensor (e.g., an image capture component 720), but instead receive images or image data from an imaging sensor located separately from and remote from the logic device 710 and / or other components of the imaging system 700. It should be understood that many other combinations of distributed implementations of the imaging system 700 are possible without departing from the scope and spirit of this disclosure.

[0096] Furthermore, in various embodiments, the various components of the imaging system 700 may be combined and / or implemented as needed or depending on the application or requirements, or may not be combined and / or implemented. In one example, the logic device 710 may be combined with the memory device 715, the image capture device 720, the image interface 725, the display device 735, the sensing device 740, and / or the network interface 745. In another example, the logic device 710 may be combined with the image capture device 720 such that certain functions of the logic device 710 are performed by circuitry (e.g., a processor, microprocessor, logic device, microcontroller, etc.) within the image capture device 720.

[0097] Figure 8 A block diagram of an example image sensor assembly 800 according to one or more embodiments of the present disclosure is shown. However, not all components shown are necessary, and one or more embodiments may include other components not shown in the figures. Changes may be made to the arrangement and type of components without departing from the spirit or scope set forth in the claims herein. Additional components, different components, and / or fewer components may be provided. In one embodiment, the image sensor assembly 800 may be an FPA, for example, implemented as Figure 1 FPA 104 and / or Figure 7 Image capture component 720 in the middle.

[0098] Image sensor assembly 800 includes a unit cell array 805, column multiplexers 810 and 815, column amplifiers 820 and 825, a row multiplexer 830, control bias and timing circuitry 835, a digital-to-analog converter (DAC) 840, and a data output buffer 845. In some aspects, operation of the unit cell array 805 and other components, and / or operation related to the unit cell array 805 and other components, can be performed according to a system clock and / or a synchronization signal (e.g., a line synchronization (LSYNC) signal). The unit cell array 805 comprises an array of unit cells. In one aspect, each unit cell may include a detector (e.g., a pixel) and interface circuitry. The interface circuitry of each unit cell may provide an output signal, such as an output voltage or an output current, in response to a detection signal (e.g., a detection current, a detection voltage) provided by the detector of the unit cell. The output signal may indicate the magnitude of EM radiation received by the detector and may be referred to as image pixel data or simply image data. Column multiplexer 815, column amplifier 820, row multiplexer 830, and data output buffer 845 are used to provide the output signal from the unit cell array 805 as a data output signal on data output line 850. The output signal on data output line 850 can be provided to components downstream of the image sensor assembly 800, such as processing circuitry (e.g., ...). Figure 7 Logic device 710 in the memory (e.g., memory) Figure 7 The memory component 715 in the middle), and the display device (e.g., Figure 7 The display component 735 and / or other components facilitate the processing, storage, and / or display of the output signal. The data output signal may be an image formed from pixel values ​​of the image sensor assembly 800. In this regard, column multiplexer 815, column amplifier 820, row multiplexer 830, and data output buffer 845 may collectively provide the ROIC (or a portion thereof) of the image sensor assembly 800. In one aspect, interface circuitry may be considered as part of the ROIC, or as an interface between the detector and the ROIC. In some embodiments, components of the image sensor assembly 800 may be implemented such that the unit cell array 805 and the ROIC are part of a single die.

[0099] Column amplifier 825 can generally represent any column processing circuit suitable for a given application (analog and / or digital), and is not limited to amplifier circuitry for analog signals. In this respect, column amplifier 825 can more generally be referred to as a column processor. Signals received by column amplifier 825, such as analog signals on an analog bus and / or digital signals on a digital bus, can be processed according to the analog or digital characteristics of the signals. As an example, column amplifier 825 may include circuitry for processing digital signals. As another example, column amplifier 825 may be the path (e.g., without processing) taken by digital signals from unit cell array 805 to column multiplexer 815. As yet another example, column amplifier 825 may include an ADC for converting analog signals to digital signals (e.g., to obtain digital count values). These digital signals can be provided to column multiplexer 815.

[0100] Each unit cell can receive a bias signal (e.g., bias voltage, bias current) to bias the unit cell's detector, thereby compensating for different response characteristics of the unit cells that may be attributable to, for example, temperature variations, manufacturing differences, and / or other factors. For example, control bias and timing circuitry 835 can generate a bias signal and provide it to the unit cells. By providing an appropriate bias signal to each unit cell, the unit cell array 805 can be effectively calibrated to provide accurate image data in response to light (e.g., visible light, IR light) incident on the detectors of the unit cells. In one aspect, control bias and timing circuitry 835 can be logic circuitry, may include logic circuitry, or may be part of logic circuitry, such as part of logic device 710.

[0101] The control bias and timing circuitry 835 can generate control signals for addressing the unit cell array 805, thereby allowing image data to be accessed and read from the addressed portion of the unit cell array 805. The unit cell array 805 can be addressed row-by-row to access and read image data, but in other embodiments, the unit cell array 805 can also be addressed column-by-column or otherwise.

[0102] The control bias and timing circuit 835 can generate a bias value and a timing control voltage. In some cases, the DAC 840 can convert a bias value received as a data input signal or a portion thereof on data input signal line 855 into a bias signal (e.g., an analog signal on analog signal line 860), which can be provided to individual unit cells through the operation of column multiplexer 810, column amplifier 820, and row multiplexer 830. For example, the DAC 840 can drive digital control signals (e.g., provided in bit form) to the appropriate analog signal level for the unit cell. In some techniques, the digital control signals of 0 or 1 can be driven to the appropriate logic low voltage level or the appropriate logic high voltage level, respectively. On the other hand, the control bias and timing circuit 835 can generate a bias signal (e.g., an analog signal) and provide the bias signal to the unit cell without using the DAC 840. In this respect, some embodiments do not include the DAC 840, data input signal line 855, and / or analog signal line 860. In one embodiment, the control bias and timing circuit 835 may be, or may include, the DAC 840. Figure 7 The logic device 710 and / or image capture unit 720 in the middle may be Figure 7 The logic device 710 and / or part of the image capture component 720 may be connected to Figure 7 The logic device 710 and / or image capture unit 720 are included.

[0103] In one embodiment, the image sensor assembly 800 may be implemented as part of an imaging device (e.g., imaging device 705). In addition to the various components of the image sensor assembly 800, the imaging device may also include one or more processors, memories, logic, displays, interfaces, optics (e.g., lenses, mirrors, beam splitters), and / or other components that may be suitable in various embodiments. In one aspect, a data output signal on data output line 850 may be provided to a processor (not shown) for further processing. For example, the data output signal may be an image formed from pixel values ​​of unit cells from the image sensor assembly 800. The processor may perform operations such as non-uniformity correction (e.g., flat field correction or other calibration techniques), spatial and / or temporal filtering, and / or other operations. The image (e.g., a processed image) may be stored in memory (e.g., external to or local to the imaging system) and / or displayed on a display device (e.g., external to and / or integrated with the imaging system). Figure 8 The various components can be implemented on a single chip or multiple chips. Furthermore, although the various components are shown as a set of separate blocks, the blocks can be combined together, or the blocks can be divided into separate blocks.

[0104] It is important to note that, in Figure 8In this design, the unit cell array 805 is depicted as an 8×8 array (e.g., 8 rows and 8 columns of unit cells). However, the unit cell array 805 can also have other sizes. By way of non-limiting examples, the unit cell array 805 may include 512×512 (e.g., 512 rows and 512 columns of unit cells), 1024×1024, 2048×2048, 4096×4096, 8192×8192, and / or other sizes. In some cases, the row size of the array (e.g., the number of detectors per row) may differ from the column size (e.g., the number of detectors per column). Examples of frame rates include 30Hz, 60Hz, and 120Hz. In one respect, each unit cell of the unit cell array 805 can represent a pixel.

[0105] Where applicable, the various embodiments provided in this disclosure may be implemented using hardware, software, or a combination of hardware and software. Furthermore, where applicable, the various hardware and / or software components described herein may be combined into composite components comprising software, hardware, and / or both, without departing from the spirit of this disclosure. Where applicable, the various hardware and / or software components described herein may be divided into sub-components comprising software, hardware, or both, without departing from the spirit of this disclosure. Furthermore, where applicable, it is contemplated that software components may be implemented as hardware components, and vice versa.

[0106] Software according to the invention, such as non-transitory instructions, program code, and / or data, can be stored on one or more non-transitory machine-readable media. Furthermore, it is envisioned that the software described herein can be implemented using one or more general-purpose or special-purpose computers and / or computer systems (networked and / or unnetworked). Where applicable, the order of the steps described herein can be changed, combined into compound steps, and / or divided into sub-steps to provide the features described herein.

[0107] The foregoing description is not intended to limit this disclosure to the precise forms disclosed or to any particular field of use. The embodiments described above illustrate the invention but do not limit it. It is foreseeable that various alternative embodiments and / or modifications to the invention may exist according to this disclosure, whether such alternative embodiments and / or modifications are explicitly described or implicit. Therefore, the scope of the invention is defined only by the appended claims.

Claims

1. A method comprising: A first set of images of a first reference object in a scene is captured by the focal plane array (FPA) of an imaging system, while the first reference object is at a temperature associated with a second reference object when the first set of images is captured; A second set of images of the second reference object are captured by the FPA; as well as The supplementary flat field correction (SFFC) value is determined based on the first set of images and the second set of images.

2. The method according to claim 1, further comprising: A first average image is determined based on the first set of images; A second average image is determined based on the second set of images; as well as The difference is determined based on the first average image and the second average image, wherein the SFFC value is based on the difference.

3. The method according to claim 1, further comprising: Image captured via the FPA; as well as A corrected image is generated based on the SFFC value and the image.

4. The method according to claim 3, further comprising: Determine the scaling factor associated with the image; as well as A scaled SFFC map is generated by applying the scaling factor to the SFFC value, wherein the corrected image is based on the scaled SFFC map and the image.

5. The method according to claim 1, further comprising: After at least a portion of the imaging system is powered on, one or more temperature characteristics associated with components of the imaging system are monitored. as well as Based at least on the one or more temperature characteristics, determine whether the portion of the imaging system has reached a steady state. After the portion of the imaging system is determined to have reached a steady state, the capture of the first set of images and the capture of the second set of images are performed.

6. The method according to claim 5, wherein, The component includes the FPA, wherein the one or more temperature characteristics include the temperature of the FPA and / or the temperature change rate of the FPA, and wherein capturing the second set of images includes capturing the second set of images when the first reference object is at a temperature associated with the second reference object at the time of capturing the second set of images.

7. The method of claim 1, further comprising storing the SFFC value in a memory device of the imaging system, wherein, The first set of images is associated with an FFC value associated with the optical path from the scene to the FPA, wherein the second set of images is associated with an FFC value associated with the optical path from the second reference object to the FPA, and wherein the SFFC value is associated with a reduction in radiometric measurement error relative to the SFFC value determined if the first set of images and / or the second set of images were captured at room temperature.

8. The method according to claim 1, wherein, The second reference object includes the internal structure of the imaging system, wherein the internal structure is selectively located between the FPA and the scene.

9. The method according to claim 8, wherein, The internal structure includes the shutter of the imaging system.

10. An imaging system, comprising: A focal plane array (FPA), wherein the focal plane array is configured as follows: Capture a first set of images of a first reference object in the scene, while the first reference object is at a temperature associated with a second reference object when capturing the first set of images; and Capture a second set of images of the second reference object; as well as A logic device configured to determine a supplementary flat field correction (SFFC) value based on the first set of images and the second set of images.

11. The imaging system according to claim 10, wherein, The logic device is configured to determine a difference based on the first set of images and the second set of images, wherein the SFFC value is based on the difference, wherein the second reference object is the shutter, and wherein the imaging system further includes the shutter.

12. The imaging system according to claim 10, wherein: The FPA is also configured to capture images; The FPA includes multiple microbolometers; and The logic device is also configured to generate a corrected image based on the SFFC value and the image.

13. The imaging system according to claim 10, wherein, The logic device is further configured to: After at least a portion of the imaging system is powered on, one or more temperature characteristics associated with components of the imaging system are received; and Based at least on the one or more temperature characteristics, determine whether the portion of the imaging system has reached a steady state. The logic device is configured to capture the first set of images and the second set of images after the portion of the imaging system is determined to have reached a steady state.

14. The imaging system of claim 13, further comprising: A memory device configured to store SFFC values; as well as A temperature sensor configured to determine the one or more temperature characteristics and transmit the one or more temperature characteristics to the logic device, wherein the SFFC value is associated with a reduced radiation measurement error relative to an SFFC value determined if the first reference object is at room temperature when the first reference object is at room temperature when the first set of images and / or the second set of images are captured by the FPA.

15. A method comprising: The first set of images of the first reference object in the scene is captured by the focal plane array (FPA) of the imaging system; A second set of images of a second reference object is captured by the FPA, while the second reference object is at a temperature associated with the FPA during the capture of the second set of images; as well as The supplementary flat field correction (SFFC) value is determined based on the first set of images and the second set of images.

16. The method of claim 15, further comprising: A first average image is determined based on the first set of images; A second average image is determined based on the second set of images; as well as The difference is determined based on the first average image and the second average image, wherein the SFFC value is based on the difference, and wherein the first set of images is captured immediately after the imaging system is powered on.

17. The method of claim 15, further comprising: Image captured via the FPA; Determine the scaling factor associated with the image; A scaled SFFC plot is generated by applying the scaling factor to the SFFC value; and A corrected image is generated based on the scaled SFFC map and the image, wherein the SFFC value is associated with a reduced radiation measurement error relative to the SFFC value determined if the second set of images were captured by the FPA when the first reference object was at room temperature.

18. The method according to claim 15, wherein, The first set of images is captured when the first reference object is at room temperature.

19. The method of claim 15, further comprising: After at least a portion of the imaging system is powered on, one or more temperature characteristics associated with components of the imaging system are monitored. as well as Based at least on the one or more temperature characteristics, determine whether the portion of the imaging system has reached a steady state. Specifically, the first set of images is captured before the portion of the imaging system is determined to have reached a steady state, and the second set of images is captured after the portion of the imaging system is determined to have reached a steady state.

20. The method according to claim 19, wherein, The first reference object is the second reference object, wherein the component includes the FPA, and wherein the one or more temperature characteristics include the temperature of the FPA and / or the rate of temperature change of the FPA.

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