Active shortwave infrared imaging system and method for generating shortwave infrared images

Abstract

An active shortwave infrared (SWIR) imaging system and a method for generating shortwave infrared images are disclosed, relating to electro-optic devices and lasers used in infrared photonics. The system includes: a pulsed illumination source operable to emit multiple pulses of SWIR radiation toward a target, the multiple pulses of radiation impacting the target and causing multiple pulses of SWIR radiation reflected from the target; an imaging receiver including multiple germanium photodiodes (PDs) operable to detect the reflected SWIR radiation, wherein the imaging receiver generates for each germanium PD a corresponding detection signal representing the reflected SWIR radiation impacting the respective germanium PD, a dark current greater than 50 μA / cm², time-dependent dark current noise, and time-independent readout noise; and a controller operable to control the activation of the imaging receiver during an integration time, during which the accumulated dark current noise does not exceed the time-independent readout noise.

Description

[0001] This application is a divisional application of application number 202080005868.4 (PCT application number PCT / IB2020 / 060011), filed on October 24, 2020, entitled "Photonic System and Method".

[0002] Cross-references to related applications

[0003] This application relates to and claims priority to U.S. Patent Application No. 16 / 662,665, filed October 24, 2019, and U.S. Provisional Patent Application Nos. 63 / 075426, filed September 8, 2020, 63 / 093,945, filed October 20, 2020, and 63 / 094,913, filed October 22, 2020, all of which are incorporated herein by reference in their entirety. Technical Field

[0004] This disclosure relates to photonic systems, methods, and computer program products. More specifically, this disclosure relates to electro-optic devices and lasers used in infrared (IR) photonics. Background Technology

[0005] Photodetecting devices, such as photodetector arrays (also called "photosensor arrays"), include a multitude of photosites, each photodetector array including one or more photodiodes and a capacitor. The photodiodes are used to detect impinging light, and the capacitors are used to store the charge supplied by the photodiodes. The capacitors can be implemented as dedicated capacitors and / or utilize the parasitic capacitances of the photodiodes, transistors, and / or other components of the photodetector array (PS). Hereinafter, in this specification and for simplicity, the term "photodetecting device" is frequently replaced by the abbreviation "PDD," the term "photodetector array" is frequently replaced by the abbreviation "PDA," and the term "photodiode" is frequently replaced by the abbreviation "PD."

[0006] The term "photosite" refers to a single sensor element (also referred to as a "sensel," as in the combination of the words "sensor" and "cell" or "sensor" and "element") in an array of multiple sensors, and is also referred to as a "sensor element," "photosensor element," "photodetector element," etc. In the following text, "photosite" is generally replaced by the abbreviation "PS." Each PS may include: one or more PDs (e.g., if a color filter array is implemented, multiple PDs detecting different portions of the spectrum may optionally be collectively referred to as a single PS). In addition to the PDs, the PS may also include: some circuitry or multiple additional components.

[0007] Dark current is a well-known phenomenon; when referring to multiple photons (PDs), it refers to the current flowing through the PD even when no photons enter the device. Dark current in PDs may be caused by the random generation of electrons and holes in a depletion region of the PD.

[0008] In some cases, it is necessary to provide numerous photodiodes characterized by a relatively high dark current to numerous photosensitive sites, while simultaneously implementing numerous capacitors with limited size. In other cases, it is necessary to provide numerous photodiodes characterized by a relatively high dark current to numerous photosensitive sites, while simultaneously reducing the impact of dark current on an output detection signal. In numerous photosensitive sites characterized by high dark current accumulation, it is beneficial to need to overcome the detrimental effects of dark current on numerous electro-optical systems. Hereafter, and for simplicity, the term "electro-optical" may be replaced with the abbreviation "EO".

[0009] Short-wave infrared (SWIR) imaging enables a range of applications that are difficult to perform using visible light imaging. These applications include electronic board inspection, solar cell inspection, product inspection, gating imaging, identification and classification, surveillance, anti-counterfeiting, process quality control, and more. Many existing indium gallium arsenide (InGaAs)-based SWIR imaging systems are expensive to manufacture and are currently limited by manufacturing capabilities.

[0010] Therefore, it would be beneficial to provide a SWIR imaging system that utilizes multiple optical receivers based on multiple PDs that are easier to integrate into surrounding electronics, thus offering greater cost-effectiveness. Summary of the Invention

[0011] According to one aspect of this disclosure, an active SWIR imaging system is provided, comprising: a pulsed illumination source operable to emit a plurality of SWIR radiation pulses toward a target, the plurality of radiation pulses impacting the target and causing a plurality of reflected SWIR radiation pulses to be reflected from the target; and an imaging receiver including a plurality of germanium (Ge) PDs operable to detect the reflected SWIR radiation, wherein the imaging receiver generates a corresponding detection signal, greater than 50 micrometers / square centimeter (μA / cm²), representing the reflected SWIR radiation impacting the respective germanium PD for each germanium PD. 2 The image receiver includes a dark current, time-dependent dark current noise, and time-independent readout noise; and a controller operable to control the activation of the image receiver during an integration time, during which an accumulated dark current noise does not exceed the time-independent readout noise.

[0012] According to one aspect of this disclosure, a method is disclosed for generating multiple SWIR images of multiple objects in a field of view (FOV) of an EO system, the method comprising: emitting at least one illumination pulse toward the FOV to cause SWIR radiation to be reflected from at least one target; triggering continuous signal acquisition initiated by an imaging receiver, the imaging receiver comprising a plurality of germanium PDs operable to detect the reflected SWIR radiation; and collecting, for each of the plurality of germanium PDs, a charge greater than 50 μA / cm² due to the triggering at least causing the SWIR reflected radiation to strike the corresponding germanium PD. 2 The dark current, dark current noise related to the integration time, and readout noise unrelated to the integration time; triggering a halt to the collection of said charge when the amount of charge collected due to dark current noise is still lower than the amount of charge collected due to readout noise unrelated to the integration time; and generating an image of the FOV based on the plurality of charge levels collected by each of the plurality of germanium PDs.

[0013] According to one aspect of this disclosure, a SWIR optical system is disclosed, the SWIR system comprising a passive Q-switched laser (also referred to herein as a "P-QS laser"), the passive Q-switched laser comprising: a gain medium comprising a gain medium crystal (GMC) material, the gain medium crystal material being a ceramic neodymium-doped yttrium aluminum garnet (Nd:YAG); and a saturable absorber (SA) rigidly connected to the gain medium, the SA comprising a ceramic SA crystal material selected from a group of doped ceramic materials consisting of: V 3+ YAG and various cobalt-doped crystalline materials; and an optical cavity, wherein the gain medium and the SA are located in the optical cavity, and the optical cavity includes a high-reflectivity mirror and an output coupler.

[0014] Therefore, in this specification and for the sake of simplicity, the term "saturable absorber" will be frequently replaced by the abbreviation "SA".

[0015] According to one aspect of this disclosure, a SWIR optical system is disclosed, the SWIR system comprising a P-QS laser, the P-QS laser comprising: a gain medium comprising a GMC material, the GMC material being a ceramic Nd:YAG; and an SA rigidly connected to the gain medium, the SA comprising a ceramic SA crystalline material selected from a group of doped ceramic materials consisting of: V 3+ YAG and various cobalt-doped crystalline materials; and an optical cavity, wherein the gain medium and the SA are located in the optical cavity, and the optical cavity includes a high-reflectivity mirror and an output coupler.

[0016] According to one aspect of this disclosure, a SWIR optical system is disclosed, comprising a P-QS laser, the P-QS laser comprising: a gain medium comprising a ceramic GMC material, the ceramic GMC material being a ceramic neodymium-doped rare earth element crystal; and an SA rigidly connected to the gain medium, the SA comprising a ceramic SA crystalline material, the ceramic SA crystalline material being selected from a group consisting of a plurality of doped crystalline materials: V 3+ YAG and various cobalt-doped crystalline materials; and an optical cavity, wherein the gain medium and the SA are located in the optical cavity, and the optical cavity includes a high-reflectivity mirror and an output coupler.

[0017] According to one aspect of this disclosure, a method for manufacturing multiple components of a P-QS laser is disclosed, the method comprising: inserting at least one first powder into a first mold; compacting the at least one first powder in the first mold to produce a first green compact; inserting at least one second powder, different from the at least one first powder, into a second mold; compacting the at least one second powder in the second mold to produce a second green compact; heating the first green compact to produce a first crystalline material; heating the second green compact to produce a second crystalline material; and attaching the second crystalline material to the first crystalline material. In such a case, one of the first and second crystalline materials is a neodymium-doped crystalline material and is a gain medium for the P-QS laser, and the other crystalline material is an SA for the P-QS laser and is selected from a group of crystalline materials consisting of: a neodymium-doped crystalline material and a doped crystalline material, the latter being selected from a group of doped crystalline materials consisting of: V 3+ YAG and various cobalt-doped crystalline materials. Similarly, in such a case, at least one of the gain medium and the SA is a ceramic crystalline material.

[0018] According to one aspect of this disclosure, a PDD is disclosed, comprising: an active PS including an active PD; a reference PS including a reference PD; a first voltage-controlled current circuit, consisting of a voltage-controlled current source or a voltage-controlled current sink, the first voltage-controlled current circuit being connected to the active PD; and a control voltage generation circuit, connected to the active voltage-controlled current circuit and the reference PS, and configured to provide a control voltage to the voltage-controlled current circuit, the control voltage having a voltage level responsive to the dark current of the reference PD to reduce the influence of the dark current of the active PD on an output of the active PS.

[0019] According to one aspect of this disclosure, a method for reducing multiple effects of dark current in a PDD is disclosed, the method comprising: determining a first control voltage based on the dark current of at least one reference PD of the PDD when the PDD is operating at a first temperature; providing the first control voltage to a first voltage control current circuit of at least one active PD of an active PS connected to the PDD, thereby causing the first voltage control current circuit to apply a first dark current resisting current in the active PS; generating a first detection current by the active PD in response to light from the active PD impacting an object in a field of view of the PDD and the dark current generated by the active PD; and outputting a first detection signal from the active PS, the amplitude of the first detection signal being less than the first detection current, in response to the first detection current and the first dark current resisting current. Dark current resisting current, thereby compensating for the influence of dark current on the first detection signal; and when the PDD operates at a second temperature at least 10 degrees Celsius (°C) higher than the first temperature, a second control voltage is determined based on the dark current of at least one reference PD of the PDD; the second control voltage is provided to the first voltage control current circuit, thereby causing the first voltage control current circuit to apply a second dark current resisting current in the active PS; a second detection current is generated by the active PD in response to light impacting the active PD originating from the object and the dark current generated by the active PD; and a second detection signal is output by the active PS, the amplitude of the second detection signal being smaller than the second detection current, in response to the second detection current and the second dark current resisting current, thereby compensating for the influence of dark current on the second detection signal. In such a case, the amplitude of the second dark current resisting current is at least twice as large as the amplitude of the first dark current resisting current.

[0020] According to one aspect of this disclosure, a method for testing a PDD is disclosed, the method comprising: providing a first voltage to a first input of an amplifier of a control voltage generation circuit, wherein a second input of the amplifier is coupled to a reference PD and a second current circuit, the second current circuit supplying a current at a level governed by an output voltage of the amplifier, thereby causing the amplifier to generate a first control voltage for a first current circuit of a PS of the PDD; reading a first output signal of the PS, the first output signal being generated by the PS in response to the current generated by the first current circuit and a PD of the PS; providing a second voltage, different from the first voltage, to the first input of the amplifier, thereby causing the amplifier to generate a second control voltage for a first current circuit; reading a second output signal of the PS, the second output signal being generated by the PS in response to the current generated by the first current circuit and a PD of the PS; and determining a defect state of a detection path of the PDD based on the first output signal and the second output signal, the detection path including the PS and a readout circuit associated with the PS.

[0021] According to one aspect of this disclosure, a system for generating multiple images is disclosed, the system comprising: a processor configured to: receive from a PDA multiple detection results of an object, the object including a high-reflectivity surface surrounded on all sides by a plurality of low-reflectivity surfaces, the plurality of detection results including first frame information of the object detected by the PDA during a first frame exposure time, and second frame information of the object detected by the PDA during a second frame exposure time, the second frame exposure time being longer than the first frame exposure time; process the first frame information based on the first frame exposure time to provide a first image, the first image including a bright region representing the high-reflectivity surface, the bright region being surrounded by a dark background representing the plurality of low-reflectivity surfaces; and process the second frame information based on the second frame exposure time to provide a second image, the second image including a dark background without a bright region.

[0022] According to one aspect of this disclosure, a system for generating multiple images is disclosed, the system comprising: a processor configured to: receive from a PDA multiple detection results of an object, the object including a high-reflectivity surface surrounded on all sides by a plurality of low-reflectivity surfaces, the plurality of detection results including first frame information of the object detected by the PDA during a first frame exposure time, and second frame information of the object detected by the PDA during a second frame exposure time, the second frame exposure time being longer than the first frame exposure time; process the first frame information based on the first frame exposure time to provide a first image, the first image including a bright region representing the high-reflectivity surface, the bright region being surrounded by a dark background representing the plurality of low-reflectivity surfaces; and process the second frame information based on the second frame exposure time to provide a second image, the second image including a dark background without a bright region.

[0023] According to one aspect of this disclosure, a method for generating image information based on data from a PDA is disclosed, the method comprising: receiving from a PDA first frame information of a low-reflectivity target including a high-reflectivity region, the first frame information indicating multiple light intensities of multiple different portions of the target detected by the PDA during a first frame exposure time; processing the first frame information based on the first frame exposure time to provide a first image, the first image including a bright region surrounded by a dark background; receiving from the PDA second frame information of the low-reflectivity target including the high-reflectivity region, the second frame information indicating multiple light intensities of the multiple different portions of the target detected by the PDA during a second frame exposure time longer than the first frame exposure time; and processing the second frame information based on the second frame exposure time to provide a second image, the second image including a dark background without a bright region.

[0024] According to one aspect of this disclosure, a non-transitory computer-readable medium is disclosed for generating image information based on data from a PDA. The non-transitory computer-readable medium includes a plurality of instructions stored thereon, which, when executed on a processor, perform the following steps: receiving from the PDA first frame information of a black target including a white area, the first frame information indicating multiple light intensities of multiple different portions of the target detected by the PDA during a first frame exposure time; processing the first frame information based on the first frame exposure time to provide a first image, the first image including a bright area surrounded by a dark background; receiving from the PDA second frame information of the black target including the white area, the second frame information indicating multiple indicator light intensities of the multiple different portions of the target detected by the PDA during a second frame exposure time longer than the first frame exposure time; and processing the second frame information based on the second frame exposure time to provide a second image, the second image including a dark background without a bright area.

[0025] According to one aspect of this disclosure, an EO system with dynamic PS availability assessment is disclosed, the system comprising: a PDA including a plurality of photosensitive sites (PS), each PS operable to output a plurality of detection signals in a plurality of different frames, wherein the detection signals output by the respective PS for a frame indicate the amount of light impacting the respective PS in a respective frame; an availability filtering module operable to determine that each PS is unavailable based on a first frame exposure time, and later to determine that the PS is available based on a second frame exposure time, the second frame exposure time being shorter than the first frame exposure time; and a processor operable to generate a plurality of images based on a plurality of frame detection levels of the plurality of PS. The processor is configured to: (i) when generating a first image based on a plurality of first frame detection levels, exclude a first detection signal of a filtered PS determined by the availability filtering module to be unavailable for the first image, and (ii) when generating a second image based on a plurality of second frame detection levels captured by the PDA after capturing the plurality of first frame detection levels, include a second detection signal of the filtered PS determined by the availability filtering module to be available for the second image.

[0026] According to one aspect of this disclosure, a method for generating image information based on data from a PDA is disclosed. The method includes: receiving first frame information, the first frame information including a first frame detection level for each of a plurality of PSs of the PDA, the first frame detection level indicating a light intensity detected by each PS during a first frame exposure time; identifying, based on the first frame exposure time, from the plurality of PSs of the PDA: a first usable PS group including a first PS, a second PS, and a third PS, and a first unusable PS group including a fourth PS; disregarding the plurality of first frame detection levels of the first unusable PS group, generating a first image based on the plurality of first frame detection levels of the first usable PS group; after receiving the first frame information, determining a second frame exposure time, the second frame exposure time being longer than the first frame exposure time; receiving second frame information, the second frame information including a second frame detection level for each of the plurality of PSs of the PDA, the second frame detection level indicating a light intensity detected by each PS during a second frame exposure time; and generating an image based on the second frame exposure time from the PDA. Identify from the plurality of PSs in DD: a second available PS group, including the first PS, and a second unavailable PS group, including the second PS, the third PS, and the fourth PS; (g) disregarding the plurality of second frame detection levels of the second unavailable PS group, generate a second image based on the plurality of second frame detection levels of the second available PS group; after receiving the second frame information, determine a third frame exposure time, the third frame exposure time being longer than the first frame exposure time and shorter than the second frame exposure time; receive the third frame information, the third frame information including information for the P A third frame detection level for each of the plurality of PSs in the DA, the third frame detection level indicating a light intensity detected by each PS during a third frame exposure time; based on the third frame exposure time, identifying from the plurality of PSs in the PDD: a third usable PS group including the first PS and the second PS, and a third unusable PS group including the third PS and the fourth PS; and (k) ignoring the plurality of third frame detection levels of the third unusable PS group, generating a third image based on the plurality of third frame detection levels of the third usable PS group.

[0027] According to one aspect of this disclosure, a non-transitory computer-readable medium is disclosed for generating image information based on data from a photodetector array (PDA). The non-transitory computer-readable medium includes a plurality of instructions stored thereon, which, when executed on a processor, perform the following steps: receiving first frame information, the first frame information including a first frame detection level for each of a plurality of photodetector arrays (PSs) of the PDA, the first frame detection level indicating a light intensity detected by each PS during a first frame exposure time; and identifying, based on the first frame exposure time, a first available... A PS group includes a first PS, a second PS, and a third PS, and a first unusable PS group includes a fourth PS; ignoring multiple first frame detection levels of the first unusable PS group, a first image is generated based on the first frame detection levels of the first usable PS group; after receiving the first frame information, a second frame exposure time is determined, the second frame exposure time being longer than the first frame exposure time; second frame information is received, the second frame information including a second frame detection level for each of the multiple PSs of the PDA, the second frame detection level indicating the detection level of the PS during the second frame exposure time. The light intensity detected by each PS; based on the second frame exposure time, identifying from the plurality of PSs in the PDD: a second usable PS group, including the first PS, and a second unusable PS group, including the second PS, the third PS, and the fourth PS; ignoring the plurality of second frame detection levels of the second unusable PS group, generating a second image based on the plurality of second frame detection levels of the second usable PS group; after receiving the second frame information, determining a third frame exposure time, the third frame exposure time being longer than the first frame exposure time and shorter than the second frame exposure time; receiving the third frame information. The third frame information includes a third frame detection level for each of the plurality of PSs of the PDA, the third frame detection level indicating a light intensity detected by each PS during a third frame exposure time; based on the third frame exposure time, identifying from the plurality of PSs of the PDA: a third usable PS group including the first PS and the second PS, and a third unusable PS group including the third PS and the fourth PS; and ignoring the plurality of third frame detection levels of the third unusable PS group, generating a third image based on the plurality of third frame detection levels of the third usable PS group. Brief description of the attached figures

[0028] The following description, with reference to the accompanying drawings listed after this paragraph, illustrates non-limiting examples of embodiments disclosed herein. Identical structures, elements, or components appearing in more than one figure may be labeled with the same numerals in all figures in which they appear. The drawings and description are intended to illustrate and explain the embodiments disclosed herein and should not be construed as limiting in any way. All drawings illustrate apparatus or flowcharts according to numerous examples of the currently disclosed subject matter. In the drawings:

[0029] Figure 1A , Figure 1B and Figure 1C This is illustrated by several schematic block diagrams illustrating multiple active SWIR imaging systems.

[0030] Figure 2 This is an exemplary graph illustrating the relative magnitude of noise power after different durations of multiple integration times in a SWIR imaging system;

[0031] Figure 3A , Figure 3B and Figure 3C A flowchart and several schematic diagrams are shown, respectively, of an operation method of an active SWIR imaging system according to some embodiments;

[0032] Figure 4A , Figure 4B and Figure 4C A flowchart and several schematic diagrams are shown respectively, illustrating an exemplary operation method of an active SWIR imaging system;

[0033] Figure 5 This is a flowchart illustrating a method for generating multiple SWIR images of multiple objects in a field of view (FOV) of an EO system.

[0034] Figure 6 This is a schematic functional block diagram illustrating an example of a SWIR optical system.

[0035] Figure 7A , Figure 7B and Figure 7C These are schematic functional block diagrams illustrating various examples of P-QS lasers.

[0036] Figure 8 and Figure 9 This is a diagram illustrating several schematic functional diagrams of a SWIR optical system.

[0037] Figure 10 This is a schematic functional block diagram illustrating an example of a SWIR optical system.

[0038] Figure 11A , Figure 11B and Figure 11CA flowchart illustrating an example of a method for manufacturing multiple components of a P-QS laser is shown, along with multiple conceptual timelines for performing the method.

[0039] Figure 12A A PS is schematically shown to include a PD, which is controlled by a voltage-controlled current source;

[0040] Figure 12B A PS is schematically shown to include a PD, which is controlled by a voltage-controlled current source in a "3T" configuration.

[0041] Figure 13A and Figure 13B A PDD is shown, which includes a PS and circuitry operable to reduce the effects of dark current.

[0042] Figure 13C A PDD is shown, which includes multiple PSs and circuitry operable to reduce the effects of dark current.

[0043] Figure 14 An exemplary PDIV curve and possible operating voltage of a PDD are shown.

[0044] Figure 15 A control voltage generation circuit is shown, which is connected to a plurality of reference photosensitive sites;

[0045] Figure 16A and Figure 16B A plurality of PDDs are shown, the plurality of PDDs comprising an array of a plurality of PSs and a reference circuit based on the plurality of PDs;

[0046] Figure 17 and Figure 18 Multiple PDDs are shown, each PDD including a PS and circuitry operable to reduce the effects of dark current;

[0047] Figure 19 A PDD is illustrated, comprising optics, a processor, and multiple additional components;

[0048] Figure 20 This is a flowchart illustrating a method for compensating for dark current in a photodetector.

[0049] Figure 21 This is a flowchart illustrating a method for compensating for dark current in a photodetector.

[0050] Figure 22 This is a flowchart illustrating a method for testing a photodetector;

[0051] Figure 23 An EO system according to some embodiments is illustrated in the figures;

[0052] Figure 24 An example illustrating a method for generating image information based on data from a PDA;

[0053] Figure 25 and Figure 26 A flowchart illustrating a method for generating a model of PDA operation at different frame exposure times is shown, along with a graphical representation of the method performed on different frames of the same scene captured at different frame exposure times.

[0054] Figure 27 This is a flowchart illustrating an example of a method for generating multiple images based on different subsets of multiple PSs under different operating conditions;

[0055] Figure 28A and 28B An EO system and several exemplary target objects are illustrated.

[0056] Figure 29 This is a flowchart illustrating a method for generating image information based on data from a PDA.

[0057] It will be understood that, for the sake of simplicity and clarity, many of the elements shown in the accompanying drawings are not necessarily drawn to scale. For example, for clarity, the dimensions of some elements may be enlarged relative to others. Furthermore, where deemed appropriate, various reference numerals may be repeated across different drawings to indicate corresponding or similar elements. Detailed Implementation

[0058] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of this disclosure. However, those skilled in the art will understand that this disclosure may be practiced without these specific details. In other instances, well-known methods, processes, and components have not been described in detail so as not to obscure this disclosure.

[0059] In the illustrated drawings and description, the same reference numerals indicate those components common to different embodiments or configurations.

[0060] Unless otherwise specified, it will be apparent from the following discussion that, throughout the discussion of this specification, terms such as “processing,” “calculating,” “computing,” “determining,” “generating,” “setting,” “configuring,” “selecting,” “defining,” etc., which include computer actions and / or processes involving manipulating and / or transforming data into other data, where the data is represented as physical quantities, such as various quantities of electrons, and / or data representing said various physical objects, are used.

[0061] The terms “computer,” “processor,” and “controller” are to be interpreted broadly to encompass any kind of electronic device capable of data processing, including, by way of non-limiting example: a human computer, a server, a computing system, a communication device, a processor (such as a digital signal processor (DSP), a microcontroller, a field-programmable gate array (FPGA), an application-specific integrated circuit, etc.), any other electronic computing device, or any combination thereof.

[0062] The operations taught in this document can be performed by a computer specially constructed for the desired purpose or by a general-purpose computer specially configured for the desired purpose, through a computer program stored in a computer-readable storage medium.

[0063] As used herein, the phrases “for example,” “such as,” “for instance,” and their variations describe numerous non-limiting embodiments of the currently disclosed subject matter. References in the specification to “one case,” “some cases,” “other cases,” or their variations indicate that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the currently disclosed subject matter. Therefore, the appearance of the phrases “one case,” “some cases,” “other cases,” or their variations does not necessarily refer to the same(s) embodiments(s).

[0064] It should be understood that, for clarity, certain features of the currently disclosed subject matter described in the context of numerous individual embodiments may also be provided in combination in a single embodiment. Conversely, for brevity, various features of the currently disclosed subject matter described in the context of a single embodiment may also be provided individually or in any suitable sub-combination.

[0065] In many embodiments of the currently disclosed subject matter, one or more stages or steps illustrated in the accompanying drawings may be performed in different orders and / or one or more groups of stages may be performed simultaneously, or vice versa. The accompanying drawings illustrate a general schematic diagram of a system architecture according to an embodiment of the currently disclosed subject matter. Each module in the accompanying drawings may consist of any combination of software, hardware, and / or firmware performing the various functions defined and explained herein. The modules in the accompanying drawings may be centralized in one location or distributed in more than one location.

[0066] Any reference to a method in the specification shall be interpreted mutatis mutandis as applicable to a system capable of performing the method, and shall be interpreted mutatis mutandis as applicable to a non-transitory computer-readable medium storing a number of instructions which, once executed by a computer, cause the execution of the method.

[0067] Any reference to a system in the specification shall be interpreted mutatis mutandis as applicable to a method that can be executed by said system, and shall also be interpreted mutatis mutandis as applicable to a non-transitory computer-readable medium storing a number of instructions that can be executed by said system.

[0068] Any reference in the specification to a non-transitory computer-readable medium or similar term shall be interpreted in accordance with the ability to execute the numerous instructions stored in the non-transitory computer-readable medium, and shall be interpreted in accordance with a method executable by a computer that reads the numerous instructions stored in the non-transitory computer-readable medium.

[0069] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. The materials, methods, and examples provided herein are illustrative only and are not intended to be limiting.

[0070] The implementation of the methods and systems disclosed herein involves manual, automatic, or a combination thereof to perform or complete certain selected tasks or steps. Furthermore, the actual instruments and apparatus according to preferred embodiments of the methods and systems of this disclosure can implement several selected steps by hardware or by software on any operating system with any firmware, or a combination thereof. For example, as hardware, the multiple selected steps of this disclosure can be implemented as a chip or a circuit. As software, the multiple selected steps of this disclosure can be implemented as multiple software instructions executable by a computer using any suitable operating system. In any case, the multiple selected steps of the methods and systems of this disclosure can be described as being performed by a data processor, such as a computing platform for executing multiple instructions.

[0071] Figure 1A , Figure 1B and Figure 1C These are schematic block diagrams illustrating multiple examples of active SWIR imaging systems 100, 100' and 100" based on the currently disclosed subject matter.

[0072] As used herein, an “active” imaging system is operable to detect light arriving at the system from its field of view (FOV), detected by an imaging receiver comprising multiple photodetectors (PDs), and the multiple detection signals are processed to provide one or more images of the field of view or a portion thereof. The term “image” refers to a digital representation of a scene detected by the imaging system, the imaging system storing a color value for each element (pixel) in the image, each pixel color representing light arriving at the imaging system from a different location within the field of view (e.g., a 0.02° x 0.02° portion of the FOV, depending on the receiver optics). It should be noted that, alternatively, the imaging system may also be operable to generate other representations of various objects or light within the FOV (e.g., a depth map, a 3D model, a polygonal mesh), but the term “image” here refers to a two-dimensional (2D) image without depth data.

[0073] System 100 includes an illumination source (IS) 102 operable to emit multiple radiation pulses in the SWIR band toward one or more targets 104, causing reflected radiation from the objects to be reflected back in the direction of system 100. Figure 1AIn this designation, outgoing illumination is designated 106, and illumination reflected toward system 100 is designated 108. Many portions of the emitted radiation may also be reflected, deflected, or absorbed by the target in other directions. The term "target" refers to any object within the FOV of the imaging sensor, such as solid, liquid, flexible, and rigid objects. Some non-limiting examples of such objects include vehicles, roads, people, animals, plants, buildings, electronic devices, clouds, microscopic samples, articles under manufacture, etc. Any suitable type of illumination source 102 can be used, such as one or more lasers, one or more light-emitting diodes (LEDs), one or more impact flash lamps, any combination thereof, etc. As discussed in more detail below, illumination source 102 may optionally include one or more active lasers or one or more P-QS lasers.

[0074] System 100 also includes at least one imaging receiver (or simply "receiver") 110, which includes a plurality of germanium (Ge) pulsed light devices operable for detecting the reflected SWIR radiation. The receiver generates an electrical signal for each of the plurality of germanium PDs, the signal representing the amount of impact SWIR light within its detectable spectral range. This amount includes the amount of SWIR radiation pulsed light reflected from the target, and may also include additional SWIR light (e.g., arriving from the sun or from an external light source).

[0075] The term "germanium PD (Ge PD)" refers to any PD in which photoinduced electronic excitation (later detectable as photocurrent) occurs within the germanium, within a germanium alloy (e.g., SiGe), or at the interface between germanium (or a germanium alloy) and another material (e.g., silicon, SiGe). Specifically, the term "germanium PD" refers both to pure germanium PDs and germanium-silicon PDs. When germanium PDs containing both germanium and silicon are used, different concentrations of geranium can be used. For example, the relative fraction of germanium in a germanium PD (whether alloyed with silicon or adjacent to it) can be in the range of 5% to 99%. For example, the relative fraction of germanium in multiple germanium PDs can be between 15% and 40%. It should be noted that materials other than silicon can also be part of a germanium PD, such as aluminum, nickel, silicides, or any other suitable material. In some implementations of this disclosure, the multiple germanium PDs can be pure germanium PDs (including greater than 99.0% germanium).

[0076] It should be noted that the receiver can be implemented as a PDA fabricated on a single chip. Any of the PD arrays discussed throughout this disclosure can be used as receiver 110. The germanium PDs can be arranged in any suitable configuration, such as a rectangular matrix (rows and columns of germanium PDs), honeycomb tiling, and even an irregular configuration. Preferably, the number of germanium PDs in the receiver allows for the generation of high-resolution images. For example, the number of PDs can be on the order of 1 megapixel, 10 megapixels, or more.

[0077] In some embodiments, receiver 110 has the following specifications:

[0078] a. HFOV (Horizontal Field of View) [m]: 60

[0079] b.WD (Working Distance) [m]: 150

[0080] c. Pixel size [um]: 10

[0081] d. Resolution (on the target) [mm]: 58

[0082] e. pixels #[H]: 1,050

[0083] f. Pixels #[V]: 1112

[0084] g. Aspect ratio: 3:1

[0085] h. Viewpoint [rad]: 0.4

[0086] i. Target reflectivity [%]: 10%

[0087] j. Collection (assuming the target reflectivity is 100% and assumed to be Lambert reflectivity, the ratio of collected photons to emitted photons): 3e -9 .

[0088] In addition to the shock SWIR light as described above, the electrical signal generated by each of the plurality of germanium PDs also represents:

[0089] a. Readout noise is random and its amplitude is independent (or substantially independent) of the integration time. Examples of this noise include Nyquist Johnson noise (also known as thermal noise or kTC noise). In addition to statistical components, the readout process may introduce a DC component into the signal, but the term "readout noise" refers specifically to the random component of the signal introduced by the readout process.

[0090] b. Dark current noise is random and accumulates over the integration time (i.e., it depends on the integration time). In addition to the statistical component, the dark current will also have a current component (which may or may not be eliminated, e.g., as shown in the figure regarding...). Figures 12A to 22 The term "dark current noise" is introduced into the signal (as discussed), but refers to the random component of the signal accumulated by dark current over the integration time.

[0091] Some germanium power distribution (PDs), especially those combining germanium with another material (such as silicon), are characterized by a relatively high level of dark current. For example, the dark current of multiple germanium PDs may be greater than 50 μA / cm. 2 (Related to one surface area of ​​the PD), or even larger (e.g., greater than 100 μA / cm²). 2 Greater than 200 μA / cm 2 or greater than 500 μA / cm 2 Depending on the surface area of ​​the PD, multiple levels of dark current can be converted to 50 picoamperes (pA) or higher per germanium PD (e.g., over 100 pA, over 200 pA, over 500 pA, or over 2 nA per germanium PD). It should be noted that multiple PDs of different sizes can be used, such as approximately 10 mm². 2 Approximately 50mm 2 Approximately 100mm 2 Approximately 500mm 2 It should be noted that when the plurality of germanium PDs are subjected to different levels of nonzero bias, the plurality of germanium PDs may generate dark currents of different magnitudes (which cause, for example, a dark current greater than 50 picoamps in each of the plurality of germanium PDs).

[0092] System 100 also includes a controller 112 and an image processor 114, the controller 112 controlling the operation of receiver 110 (and optionally also controlling illumination source (IS) 102 and / or other components). Therefore, controller 112 is configured to control the activation of receiver 110 within a relatively short integration time, thereby limiting the impact of dark current noise accumulation on signal quality. For example, controller 112 may operate to control the activation of receiver 110 within an integration time during which the accumulated dark current noise does not exceed the readout noise of the irrelevant integration time.

[0093] Now for reference Figure 2 , Figure 2This is an exemplary graph illustrating the relative magnitude of noise power after different durations of multiple integration times, according to various examples of the subject matter of this disclosure. For a given laser pulse energy, the signal-to-noise ratio (SNR) is primarily determined by the noise level, which includes the dark current noise (the noise of the dark photocurrent) and thermal noise (also known as kTC noise). Figure 2 As illustrated in the exemplary graph, depending on the integration time of the germanium-based receiver 110, the dark current noise or the thermal noise dominates the SNR of the electrical signal affecting the PD. This is because the controller 112 operates within a relatively short time (in... Figure 2 The activation time of the germanium photodetector is limited within the range designated as "A". Therefore, not many electrons from dark current noise are collected, resulting in improved SNR and thus primarily being affected by thermal noise. For a longer receiver integration time, the noise originating from the dark current of the germanium photodetector will outweigh the thermal noise when affecting the receiver's SNR, leading to a degradation in receiver performance. It should be noted that... Figure 2 The graphs are for illustrative purposes only, and the dark current noise typically increases with the square root of time as it accumulates over time. (Alternatively, the y-axis can be viewed as being plotted on a matching nonlinear polynomial scale.) Similarly, at zero integration time (in which case the accumulated dark current noise is zero), the multiple axes do not intersect each other.

[0094] Returning to system 100, it should be noted that controller 112 can control the activation of receiver 110 for a shorter integration time (e.g., an integration time during which the accumulated dark current noise does not exceed half or a quarter of the readout noise). It should be noted that limiting the integration time to a very low level, unless specifically required, limits the number of multiple photosensitive signals that can be detected and degrades the SNR related to thermal noise. It should be noted that the thermal noise level in multiple readout circuits suitable for reading multiple noisy signals (requiring the collection of relatively high signal levels) introduces non-negligible readout noise, which can significantly reduce the SNR.

[0095] In some implementations, the controller 112 may apply a slightly longer integration time (e.g., an integration time during which the accumulated dark current noise does not exceed twice the readout noise or 1.5 times the readout noise).

[0096] The exemplary embodiments disclosed herein relate to multiple systems and methods for high SNR active SWIR imaging using multiple receivers including multiple germanium-based PDs. A key advantage of germanium receiver technology compared to indium gallium arsenide (InGaAs) technology is its compatibility with CMOS process flows, allowing the receiver to be manufactured as part of a CMOS production line. For example, multiple germanium PDs can be integrated into a CMOS process flow by growing multiple Ge epitaxial layers on a silicon (Si) substrate, such as using Si photonics. Therefore, multiple germanium PDs are also more cost-effective than equivalent multiple indium gallium arsenide (InGaAs) PDs.

[0097] To utilize numerous germanium diodes, an exemplary system disclosed herein is adapted to overcome the relatively high dark current limitation of many germanium diodes, typically in the range of about 50 μA / cm². This dark current problem can be overcome by using active imaging with a combination of short capture times and numerous high-power laser pulses.

[0098] Compared to indium gallium arsenide (InGaAs) technology, the use of numerous germanium photodiodes (PDs)—especially, but not limited to, those fabricated using CMOS processes—is a much cheaper solution for uncooled SWIR imaging. Unlike many prior art imaging systems, the active imaging system 100 includes a pulsed illumination source with a short illumination duration (e.g., less than 1 μS, e.g., 1 to 1000 μS) and high peak power. Despite the disadvantages of such pulsed sources (e.g., uneven illumination, and the potential for higher levels of readout noise due to more complex readout circuitry) and shorter integration times (e.g., the inability to capture a wide range of distances in a single acquisition cycle), several approaches are discussed below to overcome these disadvantages and provide numerous efficient imaging systems.

[0099] Now for reference Figure 1B and Figure 1C These diagrams schematically illustrate various other SWIR imaging systems, designated 100' and 100" according to some embodiments. Like system 100, system 100' includes an active illumination source 102A and a receiver 110. In some embodiments, imaging systems 100, 100', and 100" also include a controller 112 and an image processor 114. In some embodiments, processing of the output of receiver 110 may be performed by image processor 114, and additionally or alternatively by an external image processor (not shown). The plurality of imaging systems 100' and 100" can be many variations of imaging system 100. Any components or functions discussed with respect to system 100 can be implemented in any of systems 100' and 100" and vice versa.

[0100] The controller 112 is a computing device. In some embodiments, many functions of the controller 112 are provided within the illumination source 102 and the receiver 110, and the controller 112 is not required as a separate component. In some embodiments, the control of the imaging systems 100' and 100" is performed by the combined action of the controller 112, the illumination source 102, and the receiver 110. Additionally or alternatively, in some embodiments, the control of the imaging systems 100' and 100" may be performed by an external controller such as a vehicle electronic control unit (ECU) 120 (which may belong to a vehicle on which the imaging system has been installed).

[0101] The illumination source 102 is configured to emit a light pulse 106 in the infrared (IR) region of the electromagnetic spectrum. More specifically, the light pulse 106 includes wavelengths in the SWIR spectral band ranging from approximately 1.3 μm to 3.0 μm.

[0102] In some embodiments, such as in Figure 1B As shown, the illumination source (now labeled 102A) is an active Q-switched laser (or "active Q-type switched" laser) comprising a gain medium 122, a pump 124, a plurality of mirrors (not shown), and an active QS element 126A. In some embodiments, the QS element 126A is a modulator. After the gain medium 122 is electronically or optically pumped by the pump 124, an optical pulse is released by actively triggering the QS element 126A.

[0103] In some embodiments, such as in Figure 1C As shown, illumination source 102P is a P-QS laser, which includes a gain medium 122, a pump 124, multiple mirrors (not shown), and an SA 126P. After a passive QS light pulse is released, SA 126P allows the laser cavity to store light energy (from the gain medium 122 pumped by pump 124) until a saturation level is reached in SA 126P. To detect the release of the passive QS pulse, a QS pulse photodetector 128 is coupled to illumination source 102P. In some embodiments, QS pulse photodetector 128 is a germanium PD. The signal from QS pulse photodetector 128 is used to trigger a reception process in receiver 110, such that receiver 110 will be activated after a time period suitable for the distance to the target 104 to be imaged. This time period is derived as follows (reference 126P). Figure 3B , Figure 3C , Figure 4B and Figure 4C Further description.

[0104] In some embodiments, the duration of the laser pulse from the illumination source 102 is in the range of 100 ps to 1 microsecond. In some embodiments, the laser pulse energy is in the range of 10 microjoules to 100 millijoules. In some embodiments, the laser pulse period is on the order of 100 microseconds. In some embodiments, the laser pulse period is in the range of 1 microsecond to 100 milliseconds.

[0105] The gain medium 122 is provided in crystalline form or alternatively in ceramic form. Numerous non-limiting examples of various materials that can be used for the gain medium 122 include: Nd:YAG, Nd:YVO4, Nd:YLF, Nd:Glass, Nd:GdVO4, Nd:GGG, Nd:KGW, Nd:KYW, Nd:YALO, Nd:YAP, Nd:LSB, Nd:S-FAP, Nd:Cr:GSGG, Nd:Cr:YSGG, Nd:YSAG, Nd:Y2O3, Nd:Sc2O3, Er:Glass, Er:YAG, and so on. In some embodiments, the multiple doping levels of the gain medium can be varied based on the requirement for a particular gain. Numerous non-limiting examples of SA 126P include: Co2+:MgAl2O4, Co2+:spinel, Co2+:zinc selenide (ZnSe) and other cobalt-doped crystals, V3+:YAG, doped glass, quantum dots, semiconductor SA mirrors (SESAM), Cr4+YAG SA, and so on. Many additional ways in which the P-QS laser 102P can be realized are described below. Figure 6 As discussed in Figure 11, any variant of the laser 600 discussed can also be applied in comparison to the illumination source 102P.

[0106] Regarding the illumination source 102, it should be noted that pulsed lasers with sufficient power and short pulses are more difficult to obtain and more expensive than pulseless illumination, especially when eye-safe SWIR radiation based on solar absorption is required.

[0107] Receiver 110 may include one or more germanium PDs 118 and receiver optics 116. In some embodiments, receiver 110 includes a 2D array of a plurality of germanium PDs 118. Receiver 110 is selected to be sensitive to infrared radiation, which includes at least wavelengths emitted by illumination source 102, thereby enabling the receiver to form an imagery of the illuminated target 104 from reflected radiation 108.

[0108] The receiver optics 116 may include one or more optical elements, such as a plurality of mirrors or lenses, arranged to collect, concentrate and optionally filter the reflected electromagnetic radiation 108 and focus the electromagnetic radiation onto a focal plane of the receiver 110.

[0109] Receiver 110 generates multiple electrical signals in response to electromagnetic radiation detected by one or more germanium PDs 118 representing an image of the lighting scene. The multiple signals detected by receiver 110 can be transmitted to an internal image processor 114 or an external image processor (not shown) for processing into a SWIR image of the target 104. In some embodiments, receiver 110 is activated multiple times to create "multiple time slices," each covering a specific distance range. In some embodiments, image processor 114 combines these slices to create a single image with greater visual depth, as proposed by Gruber, Tobias, et al. "Gated2depth: Real-time Dense LiDAR from Gated Images," arXiv preprint arXiv:1902.04997 (2019), is incorporated herein by reference in its entirety.

[0110] In the automotive field, the target 104 of the image generated by the receiver 110 within the field of view (FOV) of multiple imaging systems 100' or 100" can be processed to provide various driver assistance and safety functions, such as forward collision warning (FCW), lane departure warning (LDW), traffic sign recognition (TSR), and detection of relevant entities such as pedestrians or oncoming vehicles. The generated images can also be displayed to the driver, for example, projected onto a head-up display (HUD) on the vehicle's windshield. Additionally or alternatively, the multiple imaging systems 100' or 100" can be associated with a vehicle ECU 120 to provide numerous images or videos, enabling autonomous driving in low light levels or poor visibility conditions.

[0111] In many active imaging scenarios, a light source, such as a laser, is combined with an array of multiple optical receivers. Since the germanium PD operates in the SWIR band, high-power optical pulses are feasible without exceeding eye safety regulations. For implementations in automotive scenarios, a typical pulse length is ~100 nanoseconds (ns), although longer pulse durations up to about 1 microsecond can be expected in some embodiments. Considering eye safety, a peak pulse power of ~300 kilowatts (kW) is permissible, but current laser diodes cannot practically achieve this level. Therefore, in this system, the high-power pulse is generated by a QS laser. In some embodiments, the laser is a P-QS laser to further reduce costs. In some embodiments, the laser is an active QS laser.

[0112] As used herein, the term "target" means any imaged entity, object, area, or scene. Numerous non-limiting examples of targets in various automotive applications include vehicles, pedestrians, physical obstacles, or other objects.

[0113] According to some embodiments, an active imaging system includes: an illumination source for emitting a radiation pulse toward a target, thereby causing reflected radiation from the target, wherein the illumination source includes a QS laser; and a receiver including one or more germanium PDs for receiving the reflected radiation. In some embodiments, the illumination source operates in the SWIR spectral band.

[0114] In some embodiments, the QS laser is an active QS laser. In some embodiments, the QS laser is a P-QS laser. In some embodiments, the P-QS laser includes an SA. In some embodiments, the SA is selected from the group consisting of: Co2+:MgAl2O4, Co2+:spinel, Co2+:ZnSe and other cobalt-doped crystals, V3+:YAG, doped glass, quantum dots, semiconductor SA mirrors (SESAM), and Cr4+YAG SA.

[0115] In some embodiments, the system further includes a QS pulse photodetector for detecting a radiation pulse emitted by the P-QS laser. In some embodiments, the receiver is configured to be activated for a time sufficient for the radiation pulse to travel to a target and return to the receiver. In some embodiments, the receiver is activated for an integration time during which the dark current power of the germanium PD does not exceed the kTC noise power of the germanium PD.

[0116] In some embodiments, the receiver generates a plurality of electrical signals in response to reflected radiation received by a plurality of germanium PDs, wherein the plurality of electrical signals represent an image of the target illuminated by the radiation pulse. In some embodiments, the plurality of electrical signals are processed by one of an internal image processor or an external image processor into an image of the target. In some embodiments, the image of the target is processed to provide one or more of forward collision warning, lane departure warning, traffic sign recognition, and detection of pedestrians or oncoming vehicles.

[0117] According to numerous other embodiments, a method for performing active imaging includes the steps of: releasing a light pulse through an illumination source, the illumination source including an active QS laser; and activating a receiver, including one or more germanium PDs, for a finite time period after a time sufficient for the light pulse to travel to a target and return to the QS laser, to receive a reflected light pulse reflected from the target. In some embodiments, the illumination source operates in the short-wave infrared (SWIR) spectral band. In some embodiments, the finite time period is equal to an integration time during which the dark current power of the germanium PD does not exceed one kTC noise power of the germanium PD.

[0118] In some embodiments, the receiver generates the plurality of electrical signals in response to the reflected light pulses received by the plurality of germanium PDs, wherein the plurality of electrical signals represent an image of the target illuminated by the light pulses. In some embodiments, the plurality of electrical signals are processed by one of an internal image processor or an external image processor into an image of the target. In some embodiments, the image of the target is processed to provide one or more of forward collision warning, lane departure warning, traffic sign recognition, and detection of pedestrians or oncoming vehicles.

[0119] According to numerous other embodiments, a method for performing active imaging includes the steps of: pumping a P-QS laser, the P-QS laser including an SA, to induce the release of a light pulse when the SA is saturated; detecting the release of the light pulse by a QS pulse photodetector; and, based on the detected light pulse release, activating a receiver, including one or more germanium PDs, for a finite time period after a time sufficient for the light pulse to travel to a target and return to the QS laser, the receiver receiving the reflected light pulse. In some embodiments, the QS laser operates in the short-wave infrared (SWIR) spectral band.

[0120] In some embodiments, the SA is selected from Co2+:MgAl2O4, Co2+:spinel, Co2+:ZnSe, other cobalt-doped crystals, V3+:YAG, doped glass, quantum dots, semiconductor SA mirrors (SESAM), and Cr4+YAG SA. In some embodiments, the finite time period is equal to an integration time during which the dark current power of the germanium PD does not exceed the kTC noise power of the germanium PD.

[0121] In some embodiments, the receiver generates a plurality of electrical signals in response to the reflected light pulses received by the plurality of germanium PDs, wherein the plurality of electrical signals represent an image of the target illuminated by the light pulses. In some embodiments, the plurality of electrical signals are processed by one of an internal image processor or an external image processor into an image of the target. In some embodiments, the image of the target is processed to provide one or more of forward collision warning, lane departure warning, traffic sign recognition, and detection of pedestrians or oncoming vehicles.

[0122] Exemplary embodiments relate to a system and method for high SNR active SWIR imaging using multiple germanium-based PDs. In some embodiments, the imaging system is a gated imaging system. In some embodiments, the pulsed illumination source is an active or P-QS laser.

[0123] Now for reference Figure 3A , Figure 3B and Figure 3C A flowchart and several schematic diagrams are shown, respectively, of an operation method of an active SWIR imaging system according to some embodiments. Figure 3A The process 300 shown in the figure is based on, as referenced Figure 1BThe system 100' is described. In step 302, the pump 124 of the illumination source 102A is activated to pump the gain medium 122. In step 304, the active QS element 126A emits a light pulse along the direction of a target 104 located at a distance D. In step 306, at time T, the light pulse strikes the target 104 and generates reflected radiation returning towards the system 100' and the receiver 110. In step 308, after waiting for a time T2, the receiver 110 is activated to receive the reflected radiation. The return propagation delay T2 consists of the flight time of the pulse from the illumination source 102A to the target 104 plus the flight time of the light signal reflected from the target 104. Therefore, T2 is known for a target 104 located at a distance "D" from the illumination source 102A and the receiver 110. The activation period Δt of receiver 110 is determined based on the desired depth of field (DoV). The DoV is given by 2DoV = c * Δt, where c is the speed of light. A typical Δt of 100 ns provides a depth of field of 15 meters. In step 310, the reflected radiation is received by receiver 110 over a time period of Δt. The received data from receiver 110 is processed by image processor 114 (or an external image processor) to generate a received image. Process 300 can be repeated N times in each frame, where a frame is defined as the dataset transmitted from receiver 110 to image processor 114 (or an external image processor). In some embodiments, N is between 1 and 10,000.

[0124] Now for reference Figure 4A , Figure 4B and Figure 4C A flowchart and several schematic diagrams are shown, respectively, of an exemplary operation method of an active SWIR imaging system according to some embodiments. A process 400 shown in FIG4 is based on, as referenced... Figure 1CThe system 100” is described. In step 402, the pump 124 of the illumination source 102P is activated to pump the gain medium 122 and saturate SA126P. In step 404, after reaching a saturation level, SA126P releases a light pulse along the direction of a target 430 located at a distance D. In step 406, the QS pulse photodetector 128 detects the released light pulse. In step 408, at time T, the light pulse strikes the target 430 and generates reflected radiation returning toward system 100” and receiver 110. In step 410, after a time T2 following the detection of the released light pulse by the QS pulse photodetector 128, receiver 110 is activated to receive the reflected radiation. The return propagation delay T2 includes the flight time of the pulse from the illumination source 102P to the target 430 plus the flight time of the light signal reflected from the target 430. Therefore, T2 is known for a target 430 located at a distance “D” from the illumination source 102P and the receiver 110. The activation period of Δt is determined based on the desired depth of field (DoV). In step 412, the receiver 110 receives the reflected radiation over a time period of Δt. The received data from the receiver 110 is processed by the image processor 114 (or by an external image processor) to generate a received image. Process 400 may be repeated N times in each frame. In some embodiments, N is between 1 and 10,000.

[0125] Referring to all imaging systems 100, 100', and 100", it should be noted that any of those imaging systems may include a readout circuit for reading out an accumulation of charge collected by each germanium PD after the integration time to provide the detection signal of the respective PD. Thus, unlike LIDARs or other depth sensors, the readout process can be performed after oscillations in the integration time and therefore after the signal has been irreversibly summed from multiple distances over a wide range.

[0126] Referring to all imaging systems 100, 100', and 100", optionally, receiver 110 outputs a set of detection signals representing the charge accumulated by each of a plurality of germanium PDs during the integration time, wherein the set of detection signals represents an image of the target illuminated by at least one SWIR radiation pulse.

[0127] Referring to all imaging systems 100, 100', and 100", the imaging system may optionally have at least one diffractive optical element (DOE) operable to improve the illumination uniformity of the pulsed illumination source before emitting light toward the target. As mentioned above, a high peak power pulsed light source 102 may emit a less uniform illumination distribution across different portions of the FOV. The DOE (not illustrated) can improve the uniformity of the illumination to generate multiple high-quality images of the FOV. It should be noted that equivalent illumination uniformity is generally not required in many lidar systems and other depth sensors, therefore, due to cost, system complexity, and system... Due to factors such as size, they may not contain many DOE elements. For example, in many LiDAR systems, it is irrelevant whether certain areas of the FOV receive more illumination than other parts of the FOV, as long as the entire FOV receives sufficient illumination (above a threshold that allows detection of a target at a minimum required distance). The DOE of system 100, if implemented, can be used, for example, to reduce various speckle effects. It should be noted that the various imaging systems 100, 100', and 100" may also include other types of optical devices for guiding light from the light source 102 to the FOV, such as lenses, mirrors, prisms, waveguides, etc.

[0128] Referring to all imaging systems 100, 100', and 100", controller 112 can optionally be operated to activate receiver 110 to sequentially acquire a series of gated images, each gated image representing a detection signal from a different germanium PD within a different distance range, and an image processor operable to combine the series of images into a single two-dimensional image. For example: a first image may acquire light from the imaging sensor between 0 and 50 meters (m), a second image may acquire light from the imaging sensor between 50 and 100 meters, and a third image may acquire light from... Light from the imaging sensor is between 100 and 125 meters, and the image processor 114 can combine multiple 2D images into a single 2D image. Thus, each distance range is captured with accumulated dark current noise, which is still less than the readout noise introduced by the readout circuitry, at the cost of using more light pulses and more computation. The color value (e.g., grayscale value) of each pixel in the final image can be determined based on a function of each pixel in the multiple gated images (e.g., a maximum value or a weighted average of all values).

[0129] All imaging systems 100, 100' and 100", the imaging system may be an uncooled germanium-based SWIR imaging system capable of detecting a 1m x 1m target at a distance of more than 50m with a SWIR reflectance of 20% (within the relevant spectral range).

[0130] Referring to all imaging systems 100, 100', and 100", the pulsed illumination source 102 can be a QS laser, operable to emit eye-safe laser pulses with pulse energy between 10 millijoules and 100 millijoules. While not strictly necessary, the illumination wavelength can be selected to match a solar absorption band (e.g., the illumination wavelength can be between 1.3 micrometers (μm) and 1.4 μm).

[0131] Referring to all imaging systems 100, 100', and 100", the output signal of each germanium PD used for image generation can represent a single scalar for each PD. Referring to all imaging systems 100, 100', and 100", each PD can output a cumulative signal representing multiple distances over a wide range. For example, some, most, or all of the germanium PDs in receiver 110 can output multiple detection signals, representing each of the light reflected from 20m, 40m, and 60m to the respective PD.

[0132] Another distinguishing feature of the imaging systems 100, 100', and 100" compared to many known technical systems is that the pulsed illumination is not used to freeze the rapid movement of objects in the field (as opposed to photographic flash illumination) and is also used for static scenes. Another distinguishing feature of the imaging systems 100, 100', and 100" compared to many known technical systems is that the gating of the image is not primarily used to avoid internal noise in the system, as is common with some known techniques (such as sunlight).

[0133] It should be noted that any of the components, features, operating modes, system architectures and internal relationships discussed above regarding the various systems 100, 100' and 100” can be implemented in any of the EO systems discussed below, such as the various systems 700, 1300, 1300', 1600, 1600', 1700, 1800, 1900, 2300 and 3600, if necessary.

[0134] Figure 5This is a flowchart illustrating a method 500 for generating multiple SWIR images of multiple objects in a field of view (FOV) of an EO system, according to various examples of the subject matter of this disclosure. Referring to the various examples illustrated with reference to the preceding figures, method 500 can be performed by any of a plurality of imaging systems 100, 100', and 100''. It should be noted that method 500 can also be implemented by any active imaging system described below (such as a plurality of systems 700, 1300, 1300', 1600, 1600', 1700, 1800, 1900, 2300, and 3600).

[0135] Method 500 begins with a step (or “stage”) 510 of emitting at least one illumination pulse toward the FOV, thereby causing SWIR radiation to be reflected from at least one target. Hereinafter, “step” and “stage” may be used interchangeably. Optionally, the one or more pulses may be high-peak-power pulses. For example, multiple illumination pulses may need to be used compared to a single pulse to achieve an overall higher level of illumination. Referring to numerous examples in the accompanying figures, step 510 may optionally be performed by controller 112.

[0136] Step 520 includes the initiation of continuous signal acquisition triggered by an imaging receiver comprising multiple germanium PDs (in the sense discussed above with respect to receiver 110), which is operable to detect the reflected SWIR radiation. Continuous signal acquisition in step 520 means that the charge is collected continuously and irreversibly (i.e., it is impossible to know what level of charge has been collected at any intermediate time), and not in small increments. The triggering of step 520 may be performed before step 510 (e.g., if the detection array requires a speed-up time), simultaneously with step 510, or after step 510 (e.g., starting detection at a non-zero distance from the system). Referring to the example in the accompanying drawings, step 520 may optionally be performed by controller 112.

[0137] Step 530 begins after triggering step 520 and includes collecting data for each of the plurality of germanium PDs as a result of the triggering, at least the charge greater than 50 μA / cm induced on the respective germanium PD by the SWIR reflected radiation impact. 2 The dark current, dark current noise related to the integration time, and readout noise unrelated to the integration time. Referring to the example in the accompanying drawings, step 530 may optionally be performed by receiver 110.

[0138] Step 540 includes triggering a halt to charge collection when the amount of charge collected due to dark current noise is still lower than the amount of charge collected due to readout noise accumulated over irrelevant time. The integration time is the duration from step 530 to the halt of step 540. Referring to the example in the accompanying drawings, step 540 may optionally be performed by controller 112.

[0139] Step 560 is performed after step 540, and step 560 includes generating an image of the FOV based on the charge level collected by each of the plurality of germanium PDs. As previously mentioned with respect to the plurality of imaging systems 100, 100' and 100'", the image generated in step 560 is a 2D image without depth information. Referring to the example in the accompanying drawings, step 560 may optionally be performed by the imaging processor 114.

[0140] Optionally, the cessation of collection as a result of step 540 may be followed by an optional step 550, in which a readout circuit reads a signal related to the amount of charge collected by each of the plurality of germanium PDs, amplifies the read signal, and provides the amplified signal (optionally, after further processing) to an image processor, which performs the generation of the image as described in step 560. Referring to the example in the accompanying drawings, step 550 may optionally be performed by the readout circuit (not illustrated above, but equivalent to any readout circuit discussed below, such as a readout circuit 1610, 2318, and 3630). It should be noted that step 550 is optional because other suitable methods for reading the numerous detection results from the plurality of germanium PDs can be implemented.

[0141] Optionally, the signal output by each of the multiple germanium PDs is a scalar representing the amount of light reflected from 20 meters, 40 meters, and 60 meters.

[0142] Optionally, the generation in step 560 may include generating the image based on a scalar value read for each of the plurality of germanium PDs. Optionally, the emission in step 510 may include increasing the illumination uniformity of the pulsed laser illumination by passing pulsed laser illumination (through one or more lasers) through at least one diffractive optical element (DOE) and emitting the attenuated light into the FOV. Optionally, the dark current is greater than 50 picoamperes per germanium PD. Optionally, the plurality of germanium PDs are plurality of silicon-germanium PDs (Si-Ge PDs), each of which comprises silicon and germanium. Optionally, the emission is performed using at least one active QS laser. Optionally, the emission is performed using at least one P-QS laser. Optionally, the collection is performed when the receiver is operating at a temperature above 30°C, and the image of the FOV is processed to detect multiple vehicles and multiple pedestrians within a range between 50 meters and 150 meters. Optionally, the emission includes emitting multiple illumination pulses having pulse energy between 10 and 100 millijoules at a distance of less than 1 meter into an unprotected eye of a person without damaging the eye.

[0143] As mentioned above regarding various active imaging systems 100, 100', and 100", several gated images can be combined into a single image. Optionally, method 500 may include: repeatedly emitting, triggering, collecting, and stopping. The method 500 may include: reading a detection value from the receiver for each of the plurality of germanium PDs corresponding to different distance ranges greater than 2 meters (e.g., 2.1 meters, 5 meters, 10 meters, 25 meters, 50 meters, 100 meters). In such a case, the generation of the image in step 560 may include generating a single two-dimensional image based on the plurality of detection values ​​read from different germanium PDs in different orders. It should be noted that since only a few images are captured, the plurality of gated images are not sparse (i.e., there are many pixel detection values ​​in all or most of the gated images). It should also be noted that the plurality of gated images may have overlapping distance ranges. For example, a first image may represent a distance range of 0 to 60 meters, a second image may represent a distance range of 50 to 100 meters, and a third image may represent a distance range of 90 to 120 meters.

[0144] Figures 6 to 11C The demonstration shows that various SWIR electro-optic (EO) systems and various P-QS lasers can be used in such systems, as well as various methods for operating and manufacturing such lasers.

[0145] Figure 10 This is a schematic functional block diagram illustrating one example of a SWIR optical system 700 according to various examples of the subject matter of this disclosure. System 700 includes at least a P-QS laser 600, but may also include, as... Figure 10 The diagram includes numerous additional components, such as a sensor 702 operable to sense reflected light from the FOV of the system 700, particularly reflected illumination from the laser 600 reflected from numerous external objects 910.

[0146] Referring to other examples, sensor 702 may be implemented as an imaging receiver, PDA or various photoelectric detection devices discussed in this disclosure, such as various components 110, 1300, 1300', 1600, 1600', 1700, 1800, 1900, 2302 and 3610.

[0147] A processor 710 is operable to process the various sensing results of sensor 702. The output of the processing may be an image of the field of view (FOV), a depth model of the FOV, spectral analysis of one or more portions of the FOV, information about various identified objects in the FOV, optical statistics on the FOV, or any other type of output. Referring to many other examples, processor 710 may be implemented as any of the various processors discussed in this disclosure, such as processors 114, 1908, 2304, and 3620.

[0148] A controller 712 is operable to control the activities of the laser 600 and / or the processor 710. For example, the controller 712 may include controlling the timing, synchronization, and other operating parameters of the processor 710 and / or the laser 600. Referring to numerous other examples, the controller 712 may be implemented as any of the many other controllers discussed in this disclosure, such as controllers 112, 1338, 2314, and 3640.

[0149] Optionally, system 700 may include a SWIR PDA 706 sensitive to the wavelength of the laser. Thus, the SWIR optical system can be used as an active SWIR camera, a SWIR time-of-flight (ToF) sensor, a SWIR light detection and ranging (LIDAR) sensor, etc. The ToF sensor may be sensitive to the wavelength of the laser. Optionally, the PDA may be a CMOS-based PDA sensitive to the various SWIR frequencies emitted by laser 600, such as a CMOS-based PDA designed and manufactured by TriEye LTD in Tel Aviv, Israel.

[0150] Optionally, system 700 may include a processor 710 for processing detection data from the SWIR PDA (or any other photosensitive sensor of system 700). For example, the processor may process the detection information to provide a SWIR image of a field of view (FOV) of system 700 for detecting numerous objects within the FOV, and so on. Optionally, the SWIR optical system may include a time-of-flight (ToF) SWIR sensor and a controller, the ToF SWIR sensor being sensitive to the wavelength of the laser, and the controller operable to synchronize the operation of the ToF SWIR sensor and the P-QS SWIR laser to detect a distance to at least one object in the field of view of the SWIR optical system. Optionally, system 700 may include a controller 712 operable to control one or more aspects of the operation of laser 600 or numerous other components of the system, such as a photodetector array (e.g., a focal plane array, FPA). For example, some parameters of the laser can be controlled by the controller, including timing, duration, intensity, and focusing. Although not mandatory, the controller can control the operation of the laser based on various detection results from the PDA (directly or based on the processor's processing). Optionally, the controller can be operable to control the laser pump or other types of light sources to influence various activation parameters of the laser. Optionally, the controller can be operable to dynamically change the pulse repetition rate. Optionally, the controller can be operable to control dynamic modifications to the optical shaping optics, for example, to improve a signal-to-noise ratio (SNR) in several specific areas of the field of view. Optionally, the controller can be operable to control the illumination module to dynamically change the pulse energy and / or duration (e.g., in the same way that many other P-QS lasers might do, such as changing the focusing of the pumped laser).

[0151] Further and optionally, system 700 may include temperature control (e.g., passive temperature control, active temperature control) for overall control of a temperature of the laser or one or more of its components (e.g., the pump diode). Such temperature control may include, for example, a thermoelectric cooler (TEC), a fan, a heat sink, a resistance heater under the pump diode, and so on.

[0152] Further and optionally, system 700 may include another laser used for bleaching at least one of GM 602 and SA 604. Optionally, system 700 may include an internal photosensor (e.g., one or more PDs, such as PDA 706) operable to measure the time it takes for a pulse to be generated by laser 600 (e.g., the PD described above). In such a case, controller 712 is operable to send a trigger signal to PDA 706 (or other type of camera or sensor 702) based on timing information obtained from internal photosensor 706, which detects the reflection of laser light from numerous objects in the field of view of system 700.

[0153] The primary industry requiring a large number of lasers within the aforementioned spectral range (1.3 to 1.5 μm) is the electronics industry, which uses optical data storage. This reduces the cost of these diode lasers to a few dollars per device or even less per watt. However, these lasers are not suitable for other industries, such as the automotive industry, which requires lasers with considerably high peak power and beam brightness and will be used in harsh environmental conditions.

[0154] It should be noted that there is no scientific consensus regarding the wavelength range considered to be part of the SWIR spectrum. However, for the purposes of this disclosure, the SWIR spectrum includes electromagnetic radiation with wavelengths greater than those of the visible spectrum, and the electromagnetic radiation includes at least the spectral range between 1300 and 1500 nm.

[0155] Although not limited to this application, one or more P-QS lasers 600 can be used as illumination sources 102 for any of the imaging systems 100, 100', and 100" . Lasers 600 can be used in any other EO systems requiring pulsed illumination within the SWIR spectral range, such as various lidar systems, spectrometers, and communication systems. It should be noted that the proposed lasers 600 and the various methods for manufacturing such lasers allow for the mass production of lasers operating within the SWIR spectral range at relatively low production costs.

[0156] The P-QS laser 600 includes at least a crystalline gain medium 602 (hereinafter also referred to as "GM"), a crystal SA 604, and an optical cavity 606. The crystalline material is confined within the optical cavity 606 to allow light to propagate through the gain medium 602, thereby enhancing the tendency to generate a laser beam 612 (e.g., in...). Figure 8(As shown in the diagram). The optical cavity is also known by the terms "optical resonator" and "resonating cavity," and the optical cavity includes a high-reflectivity mirror 608 (also called a "high reflector") and an output coupler 610. The following discusses unique and novel combinations of several different types of crystalline materials and the use of various fabrication techniques to manufacture lasers, thereby allowing for the mass production of numerous lasers in the aforementioned SWIR spectral range at reasonable costs. For the sake of brevity in this disclosure, general details known in the art regarding P-QS lasers are not provided herein, but such details are readily available from a wide variety of resources. As is known in the art, the saturable absorber of the laser is used as the Q-switch of the laser. The term "crystalline material" broadly includes any material in single-crystal or polycrystalline form.

[0157] The dimensions of the connected crystal gain medium and the crystal SA can depend on the purpose of designing a particular P-QS laser 600. In a non-limiting example, the combined length of the SA and the GM is between 5 and 15 mm. In a non-limiting example, the combined length of the SA and the GM is between 2 and 40 mm. In a non-limiting example, the diameter of the combination of the SA and the GM (e.g., if it is a cylinder, or confined within a hypothetical such cylinder) is between 2 and 5 mm. In a non-limiting example, the diameter of the combination of the SA and the GM is between 0.5 and 10 mm.

[0158] The P-QS laser 600 includes a gain medium crystalline material (GMC) rigidly bonded to an SA crystalline material (SAC). This rigid coupling can be achieved in any manner known in the art, such as using adhesives, diffusion bonding, composite crystal bonding, growing one on top of another, and so on. However, as described below, rigidly bonded crystalline materials in ceramic form can be achieved using simple and inexpensive methods. It should be noted that the GMC and SAC materials can be directly rigidly bonded to each other, but can optionally be rigidly bonded to each other via an intermediate material (e.g., another crystal). In some embodiments, both the gain medium and the SA can be implemented on a monolithic crystalline material by doping different dopants (e.g., those discussed below regarding SAC and GMC) onto different portions of the monolithic crystalline material, or by co-doping the monolithic crystalline material, combining two dopants (e.g., co-doped with N...). 3+ and V3+ The gain medium can be a ceramic YAG doped with the same volume of crystalline material. Alternatively, the gain medium can be grown on a single crystal saturable absorbing substrate (e.g., using liquid phase epitaxy, LPE). It should be noted that the separate GMC and SA crystalline materials discussed extensively in the following disclosures, as well as monolithic ceramic crystalline materials doped with two dopants, can also be used analogously in any of the following implementations.

[0159] Figure 7A , Figure 7B and Figure 7C This is a series of schematic functional block diagrams illustrating various examples of the P-QS laser 600 based on the currently disclosed subject matter. Figure 7A In this process, the two dopants are implemented on two portions of the ordinary crystalline material 614 (acting as both GM and SA), while Figure 7B In this embodiment, the two dopants are interchangeably implemented on a general volume of a common crystalline material 614 (in the case of the illustrated embodiment – ​​the entirety of the common crystal). Optionally, the GM and the SA can be implemented on a monolayer crystalline material doped with neodymium and at least one other material. Optionally (e.g.) Figure 7C As shown), either or both of the output coupler 610 and the high reflectivity mirror 608 can be directly bonded to one of the various crystalline materials (such as the GM or the SA, or a crystal combining the two).

[0160] At least one of SAC and GMC is a ceramic crystalline material, which is a related crystalline material (e.g., doped yttrium aluminum garnet, YAG, or doped vanadium) in a ceramic form (e.g., a polycrystalline form). Having one (especially two) ceramic forms of crystalline material allows for higher quantities and lower cost production. For example, instead of growing individual single-crystal materials in a slow and limited process, polycrystalline materials can be manufactured through powder sintering (i.e., compacting and possibly heating a powder to form a solid mass), low-temperature sintering, vacuum sintering, and the like. One of the various crystalline materials (SAC or GMC) can be sintered on top of another, thereby eliminating the need for complex and expensive processes such as polishing, diffusion bonding, or surface-activated bonding. Optionally, at least one of GMC and SAC is polycrystalline. Optionally, both GMC and SAC are polycrystalline.

[0161] The various combinations of the aforementioned GMC and SAC crystalline materials can be manufactured, and such combinations may include:

[0162] a. The GMC is a ceramic neodymium-doped yttrium aluminum garnet (Nd:YAG), and the SAC is (a) a ceramic trivalent vanadium-doped yttrium aluminum garnet (V... 3+ (a) a cobalt-doped crystalline material (Cd:YAG) or (b) a cobalt-doped ceramic crystalline material. Optionally, the cobalt-doped ceramic crystalline material may be a divalent cobalt-doped ceramic crystalline material. In those alternatives, both the Nd:YAG and the SAC selected from the above group are in ceramic form. A cobalt-doped crystalline material is a crystalline material doped with cobalt. Numerous examples include cobalt-doped spinel (Co:cobalt or Co...). 2+ MgAl2O4), cobalt-doped zinc selenide (Co 2+ :ZnSe), cobalt-doped YAG(Co 2+ (:YAG). Although not mandatory, in this option, the high reflectivity mirror and the SA can optionally be rigidly connected to the gain medium and the SA, so that the P-QS laser is a monolithic microchip P-QS laser (e.g., as shown in the image). Figure 8 and Figure 10 (As shown).

[0163] b. The GMC is ceramic-doped yttrium aluminum garnet (Nd:YAG), and the SAC is a non-ceramic SAC selected from a group of doped ceramic materials consisting of: (a) trivalent vanadium-doped yttrium aluminum garnet (V... 3+ (a) YAG and (b) cobalt-doped crystalline material. Optionally, the cobalt-doped crystalline material may be a divalent cobalt-doped crystalline material. In such a case, the high-reflectivity mirror 608 and the output coupler 610 are rigidly connected to the gain medium and the SA, making the P-QS laser 600 a monolithic microchip P-QS laser.

[0164] c. The GMC is a ceramic neodymium-doped rare earth element crystalline material, and the SAC is a ceramic crystalline material selected from a group of doped crystalline materials consisting of: (a) yttrium aluminum garnet (YAG) doped with trivalent vanadium. 3+ (a) YAG and (b) various cobalt-doped crystalline materials. Optionally, the cobalt-doped crystalline material may be a divalent cobalt-doped crystalline material. Although not mandatory, in this option, the high-reflectivity mirror 608 and the output coupler 610 may optionally be rigidly connected to the gain medium and the SA, such that the P-QS laser 600 is a monolithic microchip P-QS laser.

[0165] It should be noted that in any implementation, a doped crystalline material may be doped with more than one dopant. For example, the SAC may be doped with the main dopant disclosed above and at least one other dopant (e.g., in significantly lower amounts). A neodymium-doped rare earth element crystalline material is a crystalline material whose unit cell contains a rare earth element (one of the 15 chemical elements defined herein, including the 15 lanthanides and scandium and yttrium), and which is doped with neodymium (e.g., triple-ionized neodymium) in place of the rare earth element in a portion of the unit cell. Several non-limiting examples of neodymium-doped rare earth element crystalline materials that may be used in this disclosure are as follows:

[0166] a. Nd:YAG (as described above), Nd:KYW, Nd:YLF, and Nd:VO4, wherein the rare earth element is neodymium; b. Nd:GdVO4, Nd:GGG, and Nd:KGW, wherein the rare earth element is gadolinium;

[0167] c. Lanthanum scandium borate (Nd:LSB) doped with neodymium, wherein the rare earth element is scandium;

[0168] d. Other neodymium-doped rare earth element crystalline materials may be used, wherein the rare earth element may be yttrium, gadolinium, scandium or any other rare earth element.

[0169] The following discussion applies to any possible combination of many GMCs and many SACs.

[0170] Optionally, the GMC is directly and rigidly connected to the SAC. Alternatively, the GMC and the SAC may be indirectly connected (e.g., each of the SAC and GMC may be connected via a group of one or more intermediate crystalline materials and / or via one or more other solid materials transparent to the relevant wavelength). Optionally, one or both of the SAC and the GMC are transparent to the relevant wavelength.

[0171] Optionally, the SAC may be cobalt-doped spinel (CoCo). 2+ :MgAl2O4). Optionally, the SAC can be cobalt-doped YAG (Co:YAG). Optionally, this allows cobalt and neodymium Nd to be co-doped on the same YAG. Optionally, the SAC can be cobalt-doped zinc selenide (Co:MgAl2O4). 2+ (ZnSe). Optionally, the GMC can be a cobalt-doped ceramic crystalline material.

[0172] Optionally, the initial transmittance (T0) of the SA is between 75% and 90%. Optionally, the initial transmittance of the SA is between 78% and 82%.

[0173] The various wavelengths emitted by the laser depend on the materials used in its construction, particularly the materials and dopants of the GMC and the SAC. Examples of the various output wavelengths include wavelengths in the range of 1,300 nm and 1,500 nm. Some more specific examples include 1.32 μm or about 1.32 μm (e.g., 1.32 μm ± 3 nm), 1.34 μm or about 1.34 μm (e.g., 1.34 μm ± 3 nm), and 1.44 μm or about 1.44 μm (e.g., 1.44 μm ± 3 nm). A corresponding imager sensitive to one or more of these optical frequency ranges can be included in the SWIR optical system 700 (e.g., as shown in the image). Figure 10 (As shown).

[0174] Figure 8 and Figure 9 These are schematic functional diagrams illustrating various examples of a SWIR optical system 700 based on the currently disclosed subject matter. As demonstrated in these diagrams, the laser 600, in addition to the components discussed above, may also include numerous additional components, such as (but not limited to):

[0175] a. A light source, such as a flash lamp 616 or a laser diode 618, said laser diode 618 serving as a pump for said laser. Referring to the preceding examples, the light source may serve as pump 124.

[0176] b. A focusing optics 620 (e.g., a lens) for focusing light from the light source (e.g., 618) onto the optical axis of the laser 600.

[0177] c. A diffuser or other optical device 622 for manipulating the laser beam 612 after it leaves the optical cavity 606.

[0178] Optionally, the SWIR optical system 700 may include: optics 708 to disperse the laser across a wider field of view (FOV) to improve eye safety within the FOV. Optionally, the SWIR optical system 700 may include: optics 704 to collect reflected laser light from the FOV and guide it to the sensor 702, for example, to a photodetector array (PDA) 706, see [link to relevant documentation]. Figure 10 Optionally, the P-QS laser 600 is a diode-pumped solid-state laser (DPSSL).

[0179] Optionally, the P-QS laser 600 includes at least one diode-pumped light source and optics 620 for focusing the light from the diode-pumped light source into the optical resonator (optical cavity). Optionally, the light source is located on the optical axis (as one-end pump). Optionally, the light source can be rigidly connected to a high-reflectivity mirror 608 or SA 604, such that the light source is part of a monolithic microchip P-QS laser. Optionally, the light source of the laser may include one or more vertical-cavity surface-emitting laser (VCSEL) arrays. Optionally, the P-QS laser 600 includes at least one VCSEL array and optics for focusing the light from the VCSEL array into the optical resonator. The wavelength emitted by the light source (e.g., the laser pump) may depend on the various crystalline materials and / or dopants used in the laser. Some exemplary pumping wavelengths that may be emitted by the pump include: 808 nm or about 808 nm, 869 nm or about 869 nm, and about nine hundred and some nm.

[0180] The power of the laser may depend on its intended application. For example, the laser output power may be between 1W and 5W. Alternatively, the laser output power may be between 5W and 15W. Or, the laser output power may be between 15W and 50W. Or, the laser output power may be between 50W and 200W. Or, the laser output power may be higher than 200W.

[0181] The QS laser 600 is a single-pulse laser and can have different frequencies (repetition rates), different pulse energies, and different pulse durations, depending on its intended application. For example, the repetition rate of the laser can be between 10 Hz and 50 Hz. For example, the repetition rate of the laser can be between 50 Hz and 150 Hz. For example, the pulse energy of the laser can be between 0.1 mJ and 1 mJ. For example, the pulse energy of the laser can be between 1 mJ and 2 mJ. For example, the pulse energy of the laser can be between 2 mJ and 5 mJ. For example, the pulse energy of the laser can be higher than 5 mJ. For example, the pulse duration of the laser can be between 10 ns and 100 ns. For example, the pulse duration of the laser can be between 0.1 μs and 100 μs. For example, the pulse duration of the laser can be between 100 μs and 1 ms. The size of the laser can also be varied, for example, depending on the size of its components. For example, the size of the laser can be X1 x X2 x X3, where each dimension (X1, X2, and X3) is between 10 mm and 100 mm, between 20 mm and 200 mm, and so on. The output coupling mirror can be flat, curved, or slightly curved.

[0182] Optionally, in addition to the gain medium and the SA, the laser 600 may further include undoped YAG to prevent heat accumulation in an absorption region of the gain medium. The undoped YAG may optionally be shaped as a cylinder (e.g., a concentric cylinder) surrounding the gain medium and the SA.

[0183] Figure 11A This is a flowchart illustrating an example of method 1100 according to the currently disclosed subject matter. Method 1100 is a method for manufacturing multiple components for a P-QS laser, said P-QS laser being, for example, but not limited to, the P-QS laser 600 described above. Referring to the various examples illustrated with respect to the preceding figures, said P-QS laser may be laser 600. It should be noted that any variations discussed with respect to laser 600 or with respect to a component thereof may also be implemented with respect to the multiple components of said P-QS laser manufactured in method 1100 or with respect to a corresponding component thereof, and vice versa.

[0184] Method 1100 begins with step 1102, which involves inserting at least one first powder into a first mold. Step 1102 is then processed in method 1100 to produce a first crystalline material. This first crystalline material serves as the GM or SA of the P-QS laser. In some implementations, the gain medium of the laser is first fabricated (e.g., by sintering), and then the SA is fabricated on top of the previously fabricated GM (e.g., by sintering). In other implementations, the SA of the laser is first fabricated, and then the GM is fabricated on top of the previously fabricated SA. In still other implementations, the SA and GM are fabricated independently of each other and coupled to form a single rigid body. This coupling may be performed as part of heating, sintering, or a later step.

[0185] Step 1104 of method 1100 includes inserting at least one second powder into a second mold, said at least one second powder being different from said at least one first powder. The at least one second powder is later processed in method 1100 to produce a second crystalline material. The second crystalline material is used as the GM or SA of the P-QS laser (so that one of the SA and the GM is made of the first crystalline material, and the other functionality is made of the second crystalline material).

[0186] The second mold may be different from the first mold. Alternatively, the second mold may be the same as the first mold. In such a case, the at least one second powder may be inserted, for example, on top of the at least one first powder (or, if already formed, on top of the first green body), beside it, around it, and so on. The insertion of the at least one second powder into the same mold as the at least one first powder (if implemented) may be performed before, after, or during the processing of the at least one first powder into the first green body.

[0187] The first powder and / or the second powder may include crushed YAG (or any other of the aforementioned materials, such as spinel, MgAl2O4, ZnSe) and doped materials (e.g., N). 3+ V 3+ The first powder and / or the second powder may include: materials for forming YAG (or any other of the above materials, such as spinel, MgAl2O4, ZnSe) and doping materials (such as N). 3+ V 3+ Co).

[0188] Step 1106 is performed after step 1102 and includes compacting the at least one first powder in the first mold to produce a first green body. Step 1104 is performed after step 1108 and includes compacting the at least one second powder in the second mold to produce a second green body. If the at least one first powder and the at least one second powder are packed into the same mold in steps 1102 and 1104, the compaction of the powders can be performed simultaneously in steps 1106 and 1108 (e.g., pressing the at least one second powder, which in turn compresses the at least one first powder against the mold), but this is not necessary. For example, step 1104 (and therefore also step 1108) can optionally be performed after the compression in step 1106.

[0189] Step 1110 includes heating the first green compact to yield a first crystalline material. Step 1112 includes heating the second green compact to yield a second crystalline material. In different embodiments, the heating of the first crystal may be performed before, simultaneously, partially simultaneously, or after each of steps 1106 and 1110.

[0190] Optionally, the heating of the first green blank at step 1110 precedes the compaction of the at least one second powder in step 1108 (and possibly in step 1104) (and possibly also precedes the insertion). The first green blank and the second green blank can be heated separately (e.g., at different times, at different temperatures, for different durations). The first green blank and the second green blank can be heated together (e.g., in the same oven), or connected to each other during heating, or not. The first green blank and the second green blank can undergo different heating regimes, which can share a portion of co-heating while being heated separately in other portions of the heating regime. For example, one or both of the first green blank and the second green blank can be heated separately from the other green blank, and then the two green blanks can be heated together (e.g., after coupling, but not necessarily). Optionally, the heating of the first green blank and the heating of the second green blank include simultaneously heating the first green blank and the second green blank in a single oven. It should be noted that, optionally, the coupling in step 1114 is a result of simultaneously heating the two green blanks in a single oven. It should also be noted that, optionally, the coupling in step 1114 is accomplished by co-sintering the two green blanks after they are physically connected to each other.

[0191] Step 1114 includes coupling the second crystalline material to the first crystalline material. This coupling can be performed using any coupling method known in the art, with several non-limiting examples discussed above regarding the P-QS laser 600. It should be noted that the coupling can have several sub-steps, some of which may be intertwined with different steps in steps 1106, 1108, 1110, and 1112 in different ways in various embodiments. The coupling results in a single rigid crystalline body comprising the GM and the SA.

[0192] It should be noted that method 1100 may include a plurality of additional steps used in the manufacture of numerous crystals (particularly in the manufacture of ceramic or non-ceramic polycrystalline compounds of polycrystalline materials bonded together). A few non-limiting examples include powder preparation, binder burn-out, densification, annealing, polishing (as described below if desired), and the like.

[0193] The GM of the P-QS laser in method 1100 (which, as described above, may be the first crystalline material or the second crystalline material) is a neodymium-doped crystalline material. The SA of the P-QS laser in method 1100 (which, as described above, may be the first crystalline material or the second crystalline material) is selected from a group of crystalline materials consisting of: (a) a neodymium-doped crystalline material, and (b) a doped crystalline material selected from yttrium aluminum garnet (YAG) doped with trivalent vanadium. 3+ This refers to a group of multiple doped crystalline materials, including YAG and cobalt-doped crystalline materials. At least one of GM and SA is a ceramic crystalline material. Optionally, both GM and SA are ceramic crystalline materials. Optionally, at least one of GM and SA is a polycrystalline material. Optionally, both GM and SA are polycrystalline materials.

[0194] Although many additional steps in the manufacturing process can be performed between different stages of method 1100, in at least some implementations, it is not necessary to polish the first material before the second material is bonded during the sintering process.

[0195] Regarding the various combinations of crystalline materials that can be produced in method 1100, such combinations may include:

[0196] 1. The GMC is a ceramic neodymium-doped yttrium aluminum garnet (Nd:YAG), and the SAC is (a) a ceramic trivalent vanadium-doped yttrium aluminum garnet (V... 3+ (a) a cobalt-doped crystalline material, or (b) a ceramic cobalt-doped crystalline material. In this alternative, both Nd:YAG and SAC selected from the above group are in ceramic form. A cobalt-doped crystalline material is a crystalline material doped with cobalt. Numerous examples include cobalt-doped spinel (Co:Spinel or Co...). 2+ MgAl2O4), cobalt-doped zinc selenide (Co 2+ (ZnSe). Although not mandatory, in this option the high reflectivity mirror and the output coupler can optionally be rigidly connected to the GM and the SA, making the P-QS laser a monolithic microchip P-QS laser.

[0197] 2. The GMC is a ceramic neodymium-doped yttrium aluminum garnet (Nd:YAG), and the SAC is a non-ceramic SAC selected from a group of doped ceramic materials consisting of: (a) trivalent vanadium-doped yttrium aluminum garnet (V... 3+ (a) YAG and (b) various cobalt-doped crystalline materials. In this case, the high-reflectivity mirror and the output coupler are rigidly connected to the GM and the SA, making the P-QS laser a monolithic microchip P-QS laser.

[0198] 3. The GMC is a ceramic neodymium-doped rare earth element crystalline material, and the SAC is selected from a group of doped crystalline materials consisting of: (a) yttrium aluminum garnet (YAG) doped with trivalent vanadium. 3+ (a) YAG and (b) various cobalt-doped crystalline materials. Although not mandatory, in this option the high-reflectivity mirror and the output coupler can optionally be rigidly connected to the GM and the SA, making the P-QS laser a monolithic microchip P-QS laser.

[0199] Referring generally to method 1100, it should be noted that one or both of the SAC and the GMC (and optionally one or more intermediate connecting crystalline materials, if any) are transparent to the relevant wavelength (e.g., SWIR radiation).

[0200] Figure 11B and Figure 11C Several conceptual timelines for performing method 1100 are included, based on numerous examples of the currently disclosed subject matter. For the sake of simplicity in the figures, it is assumed that the SA is a result of the treatment of at least one first powder, and that the gain medium is a result of the treatment of at least one second powder. As stated above, the roles are interchangeable.

[0201] Figure 12A An example of a PS, designated 1200, is schematically shown, comprising a photodetector (e.g., PD) 1202 controlled by a voltage-controlled current source (VCCS) 1204. It should be noted that the voltage-controlled current source 1204 may optionally be external to the PS 1200 (e.g., if a single VCCS 1204 provides current to multiple PSs). The VCCS 1204 is a slave current source that delivers a current proportional to a control voltage (labeled VCTRL in the figure). The numerous PSs and numerous PDDs disclosed in this disclosure may include any suitable type of VCCS. Other (“additional”) components of the PS 1200 (not shown) are collectively represented by a general block 1206. When used for sensing, a plurality of PSs such as PS1200 and a plurality of photodetectors such as photodetector 1202 may also be referred to hereinafter as “active” or “non-reference” plurality of PSs / plastic detectors (different from the plurality of PSs and photodetectors used to determine the input of the control voltage of the current source).

[0202] Figure 12B Another example of a PS designated 1200' is shown schematically; it is an example of a PS1200. In PS1200', the other component 1206 is in the form of a "3T" (triple transistor) structure. Any other suitable circuitry can be used as numerous additional components 1206.

[0203] Current source 1204 can be used to provide a current of the same magnitude but opposite direction to the dark current generated by PD 1202, thereby eliminating (or at least reducing) the dark current. This is particularly useful if PD 1202 is characterized by high dark current characteristics. In this way, the charge flowing from the PD to a capacitor (as described above, which can be provided by one or more capacitors, by the parasitic capacitance of the PS, or a combination thereof), and the charge caused by the dark current, can be canceled out. In particular, the provision of a current by current source 1204 with an amplitude substantially equal to the dark current means that the provided current will not cancel out the actual electrical signal generated by PD 1202 due to the detected light impact on PD 1202.

[0204] Figure 13AA PDD 1300 is shown as one of the many examples of the subject matter currently disclosed. The PDD 1300 includes circuitry capable of controllably matching the current supplied by current source 1204 with the dark current generated by PD 1202, even when the generated dark current is not constant (it varies over time). It should be noted that the level of the dark current generated by PD 1202 can depend on various parameters, such as the operating temperature and the bias voltage supplied to the PD (which can also change from time to time).

[0205] The PDD 1300 reduces the impact of dark current within the PS1200 (rather than in later stages of signal processing, whether analog or digital), enabling the use of a relatively small capacitor without saturating it or reducing its linearity in response to the collected charge.

[0206] PDD 1300 includes a PS1200 and a reference PS1310. The PS1200 is used to detect the light of an impact, and the output of the reference PS1310 is used by additional circuitry (discussed below) to reduce or eliminate the effects of dark current in the PS1200. Like the PS1200 (and 1200'), the reference PS1310 includes a PD 1302, a VCCS 1304, and optional other circuitry (“other components”, collectively referred to as 1306). In some examples, the reference PS1310 of PDD 1300 may be the same as the PS1200 of PDD 1300. Alternatively, any one or more components of PS1310 may be the same as a corresponding component of PS1200. For example, PD 1302 may be substantially the same as PD 1202. For example, VCCS 1304 may be the same as VCCS 1204. Optionally, any one or more components of the PS1310 may differ from those of the many components of the PS1200 (e.g., PDs, current sources, additional circuitry). It should be noted that substantially identical components of the PS1200 and PS1310 (e.g., PDs, current sources, additional circuitry) may be operated under different operating conditions. For example, different biases may be supplied to multiple PDs 1202 and 1302. For example, different components of additional components 1206 and 1306 may be operated with different parameters, or selectively connected / disconnected, even when their structures are substantially identical. For simplicity and clarity, the many components of the PS1310 are numbered 1302 (for the PD), 1304 (for the VCCS), and 1306 (for the additional circuitry), but this does not imply that these components are different from components 1202, 1204, and 1206.

[0207] In some examples, reference circuitry 1306 may be omitted or disconnected so as not to affect the determination of the dark current. PD 1202 can operate under any of the following conditions: reverse bias, forward bias, zero bias, or selectively between any two or three of the above biases (e.g., controlled by a controller such as controller 1338 discussed below). PD 1302 can operate under any of the following conditions: reverse bias, forward bias, zero bias, or selectively between any two or three of the above biases (e.g., controlled by a controller such as controller 1338 discussed below). Many PDs 1202 and 1302 can operate at substantially the same bias (e.g., approximately -5V, approximately 0V, approximately +0.7V), which is not necessary (e.g., when testing PDD 1300, as discussed in more detail below). Optionally, a single PS of the PDD 1300 may sometimes operate as PS1200 (detecting light from a field of view (FOV) of the PDD 1300), and sometimes as PS1310 (whose detection signal output is used to determine a control voltage for a VCCS of another PS 1200 of the PDD). Optionally, the roles of the "active" PS and the reference PS used to detect the impact light can be interchanged. The PDD 1300 also includes a control-voltage generating circuitry 1340, which includes at least an amplifier 1318 and multiple electrical connections to multiple PSs of the PDD 1300. The amplifier 1318 has at least two inputs: a first input 1320 and a second input 1322. The first input 1320 of the amplifier 1318 is supplied with a first input voltage (V). FI The first input voltage can be directly controlled by a controller (implemented on the PDD 1300, on an external system, or a combination thereof), or derived from other voltages in the system (which in turn can be controlled by the controller). The second input 1322 of the amplifier 1318 is connected to the cathode of the PD 1302 (refer to the PS1310).

[0208] In a first use case example, PD 1202 is held at a first voltage (also referred to as "anode voltage"), denoted as V. A A second voltage (also known as the "cathode voltage"), denoted as V, is used in conjunction with a second voltage (also known as the "cathode voltage"). CA working bias voltage between the anode and cathode voltages. The anode voltage can be directly controlled by the controller (implemented on the PDD 1300, on an external system, or a combination thereof), or derived from other voltages in the system (which can in turn be controlled by the controller). The cathode voltage can be directly controlled by the controller (implemented on the PDD 1300, on an external system, or a combination thereof), or derived from other voltages in the system (which can in turn be controlled by the controller). The anode voltage V A and the cathode voltage V C Each of these can remain constant or not constant over time. For example: the anode voltage V A It can be supplied by a constant source (e.g., from an external controller via a pad). Depending on the implementation, the cathode voltage V C It can be substantially constant or change over time. For example, when a 3T structure is used in a PS1200, V may change due to the operation of numerous additional components 1206 and / or current from PD 1202. C Changes over time. V C It may optionally be determined / controlled / influenced by a number of additional components 1206 (instead of the reference circuit).

[0209] The VCCS1204 is used to provide (feed) a current to the cathode of PD 1202 to counteract the dark current generated by PD 1202. It should be noted that at other times, the VCCS1204 can feed other currents for other purposes (such as for calibrating or testing PDD 1300). The level of the current generated by the VCCS1204 is controlled in response to an output voltage of amplifier 1318. The control voltage used to control the VCCS1204 is denoted as V. CTRL This can be the same as one of the output voltages of amplifier 1318 (as shown in the figure). Alternatively, V CTRL The output voltage of amplifier 1318 can be derived (e.g., due to the resistance or impedance between the output of amplifier 1318 and VCCS1204).

[0210] To counteract (or at least reduce) the effect of the dark current of PD 1202 on the output signal of PS1200, PDD 1300 can subject PD 1302 to a substantially identical bias voltage as PD 1202. For example, when PD 1302 and PD 1202 are substantially identical, subjecting PD 1302 and PD 1202 to the same bias voltage can be used. One method of supplying the same bias voltage to both PDs (1202 and 1302) is to supply the anode voltage V of PD 1302. A(Where the supplied voltage is designated as VRPA, and RPA stands for "reference PD anode"), and the cathode of PD 1302 is supplied with a voltage V. C (where the applied voltage is labeled as V) RPC RPC stands for "reference PD cathode". Another way to supply the same bias voltage is to use V RPA =V A +ΔV is supplied to the anode of PD 1302, which will V RPC =V C +ΔV is supplied to the cathode of PD 1302. Optionally, the anode voltage V A Reference anode voltage V RPA Alternatively, both can be supplied by an external power source (such as a printed circuit board (PCB) connected via the PDD 1300).

[0211] As described above, the first input 1320 of amplifier 1318 is supplied with a first input voltage V. FI The second input 1322 of amplifier 1318 is connected to the cathode of PD 1302. Operation of amplifier 1318 reduces the voltage difference between its two inputs (1320 and 1322), thereby causing the voltage at the second input 1322 to tend to be supplied to the first input (V). FI The same controlled voltage. Now refer to Figure 13B The dark current on PD 1302 (hereinafter referred to as DC) 参考 The circuit shown in the figure is represented by arrow 1352. Figure 13A (The circuit is the same). During the period when PD 1202 remains dark, the current on PD 1302 is equal to the dark current of PD 1202. PDD 1300 (or any system component connected to or adjacent to it) may block light to PD 1302, thus keeping it dark. This blocking can be done through physical barriers (such as opaque barriers), optical devices (such as various steering lenses), electronic shutters, and the like. In the following description, it is assumed that all the current on PD 1302 is the dark current generated by PD 1302. Alternatively, if PD 1302 is exposed to light (such as various low-level known stray light in the system), a current source can be implemented to deflect the known light source signal, or the first input voltage V. FIIt can be modified to compensate (at least partially) for stray illumination. The barriers, optics or other specialized components designed to keep light away from PD 1302 can be implemented at the wafer level (on the same wafer on which PDD 1300 is manufactured), can be attached to that wafer (e.g., using adhesive), can be rigidly attached to a housing in which the wafer is mounted, and so on.

[0212] Assume V FI If the current is constant (or slowly changing), then the output of VCCS1304 (indicated by arrow 1354) must be equal in magnitude to the dark current of PD 1302 (DC). 参考 This means that VCCS1304 provides a charge carrier for the dark current consumption of PD 1302, thereby allowing the voltage to remain at VFI. Since the output of VCCS1304 is controlled by VCTRL in response to the output of amplifier 1318, amplifier 1318 is operated to output the desired output such that VCTRL will control the output of VCCS 1304, which will be in amplitude the same as the dark current on PD 1302.

[0213] If PD 1202 and PD 1302 are substantially identical and VCCS1204 and VCCS1304 are substantially identical, then the output of amplifier 1318 will also cause VCCS1204 to provide the same level of current (DC) to the cathode of PD 1202. 参考 In such a case, in order for the output of VCCS1204 to cancel the dark current (hereinafter referred to as DC) generated by PD 1202... 有源PD This requires that PD 1202 and PD 1302 both generate a similar level of dark current. To ensure that the two PDs (1202 and 1302) are subjected to the same bias (which will cause both PDs to generate substantially the same level of dark current because both PDs are maintained under substantially the same conditions, such as temperature), the voltage supplied to the first input of amplifier 1318 is determined in response to the anode and cathode voltages of PD 1202 and the anode voltage of PD 1302. For example: if V A equals V RPA Then it equals V C V FI It can be provided to the first input 1320. It should be noted that V C It can change over time and is not necessarily determined by a single controller (e.g., V). CThis can be determined as a result of numerous additional components 1206. If PD 1202 differs from PD 1302 and / or if VCCS1204 differs from VCCS1304, the output of amplifier 1318 can be modified by matching numerous electrical components (not shown) between amplifier 1318 and VCCS1204 to provide a relevant control voltage to VCCS1204 (e.g., if the dark current on PD 1202 is known to be linearly related to the dark current on PD 1302, the output of amplifier 1318 can be modified according to the linear relationship). Another method of supplying the same bias voltage is to use V RPA =V A +ΔV is supplied to the anode of PD 1302, and V RPC =V C +ΔV is supplied to the cathode of PD 1302.

[0214] Figure 13C A photodetector 1300', illustrating numerous examples according to the currently disclosed subject matter, includes a plurality of PS1200s. A PDD 1300' includes all components of the PDD 1300, as well as numerous additional PS1200s. The different PSs of the PDD 1300' are substantially identical to each other (e.g., all are part of a two-dimensional PDA), and therefore the numerous PDs 1302 of the different PS1200s generate similar dark currents. Therefore, the same control voltage V... CTRL All VCCS1204s supplied to the different PS1200s of PDD 1300' cause these VCCS1204s to cancel (or at least reduce) the effects of the dark current generated by the individual PD 1202. Any of the options discussed above with respect to PDD 1300 can be applied analogously to PDD 1300'.

[0215] In some cases (for example, if V) C (Not constant and / or unknown), can provide a first input voltage V FI (for example, via a controller), the first input voltage V FI It was chosen to induce a dark current on PD 1302 similar to that on PD 1202.

[0216] Now for reference Figure 14 This illustrates an exemplary PD IV curve 1400 according to numerous examples of the subject matter currently disclosed. For ease of illustration, curve 1400 represents the IV curves of both PD 1302 and PD 1202, which, for the purposes of this description, are assumed to be substantially identical and subjected to the same anode voltage (i.e., V1 for the purposes of this description). A =V RPAThe IV curve 1400 is relatively flat between voltages 1402 and 1404, meaning that different bias voltages between 1402 and 1404 supplied to the relevant PD will produce similar levels of dark current. If V C V varies within a cathode voltage range, given a known V A This means that the bias voltage on PD 1202 is limited between voltages 1402 and 1404, and then supplying a VRPC will cause the bias voltage on PD 1302 to also be between voltages 1402 and 1404, causing the VCCS1204 output to be sufficiently similar to DC. 有源PD The current remains constant even when PD 1202 and PD 1302 are subjected to different bias voltages. Under such circumstances, V RPC The bias can be within the cathode voltage range (as shown by equivalent voltage 1414) or outside of it (but still maintaining the bias on PD 1302 between 1402 and 1404), as demonstrated by equivalent voltage 1412. Modifications to other configurations, such as those discussed above, can be implemented accordingly. It should be noted that different biases can also be supplied to different PDs 1202 and 1302 for other reasons. For example, different biases can be supplied as part of the testing or calibration of the PDA.

[0217] In real-world applications, different power supplies (PSs) within a single power supply (PDD) may not be identical in their individual components, and the operation of these PSs may not be exactly the same. Within a power supply array, numerous power supplies may differ from one another, and their dark currents may vary (e.g., due to manufacturing variations, slight temperature differences, etc.).

[0218] Figure 15 A control voltage generation circuit 1340 according to various embodiments of the present invention is shown, the control voltage generation circuit 1340 being connected to a plurality of reference photosensitive sites 1310 (collectively referred to as 1500). Figure 15 The circuit (also referred to as reference circuit 1500) can be used to determine a control voltage (denoted as V) for one or more VCCS1204 corresponding to one or more PS1310s and any PDD changes discussed in this disclosure for multiple PDDs 1300, 1300'. CTRLSpecifically, reference circuit 1500 can be used to determine a control voltage based on data collected from multiple reference PS1310s that differ to some extent (e.g., due to manufacturing inaccuracies, different operating conditions, etc.) to counteract (or limit) the effects of dark currents in one or more PS1200s of a PDD. As previously mentioned, the dark currents of many PDs, even if similar, may differ from one another. It should be noted that in some PD technologies, many PDs intended to be identical may feature many dark currents that differ by a factor of x1.5, x2, x4, or even more. The averaging mechanism discussed herein even allows for compensation for such significant differences (e.g., in manufacturing). In cases where amplifier 1318 is connected to multiple reference PS1310s to average the many levels of dark current of several PS1310s, such many PS1310s are kept in darkness, for example using any of the mechanisms discussed above. The many voltages supplied to the different VCCS1304s of the various PS1310s are short-circuited, such that all VCCS1304s receive substantially the same control voltage. The various cathode voltages of the different reference PDs 1302 are short-circuited to different networks. Thus, although the currents in the different reference PS1310s are slightly different from each other (due to the slight differences between the various reference PS1310s), the average control voltage supplied to one or more PS1200s of each PDD (which may also be slightly different from each other and from the reference PS1310) is accurate enough to cancel out the effect of dark current on the different PS1200s in a sufficiently uniform manner. Optionally, the output voltage of a single amplifier 1318 is supplied to all PS1200s and all reference PS1310s. Optionally, the various selected PDs for the PDDs have a flat IV response (as described above, for example, regarding...). Figure 14 This allows the average control voltage discussed for the reference circuit 1500 to offset the dark current in the various PS1200s to a very good degree. Figure 16A and Figure 16BNumerous non-limiting examples of PDDs are provided, including multiple reference PS1310s whose averaged output signals are used to modify the multiple output signals of multiple active PS1200s (e.g., to reduce the effect of dark current in the output signals). Different configurations, geometries, and numerical ratios can be implemented between the multiple reference PS1310s and the multiple active PS1200s of a single PDD. For example, in a rectangular photodetector array comprising multiple PSs arranged in multiple rows and columns, a whole row of PSs (e.g., 1,000 PSs) or several rows or columns of PSs can be used as multiple reference PS1310s (and optionally kept in darkness), while the remainder of the array receives the control signal based on averaging the outputs of those reference PS rows. This method of generating control current significantly reduces the effect of dark current by eliminating the averaged dark current, leaving only PS-to-PS variations.

[0219] Figure 16A and Figure 16B Multiple photoelectric detection devices, including an array of multiple photodetectors and a reference circuit based on multiple photodetectors, are shown as numerous examples of the subject matter of this disclosure. PDD 1600 ( Figure 16A (as shown) and PDD1600' ( Figure 16B As shown (a variant of PDD 1600), it includes all the components of PDD 1300, as well as multiple additional PS1200 and PS1310. Optionally, the different PSs of PDD 1600 (and PDD 1600' respectively) are substantially identical to each other. Any options discussed above regarding the multiple PDDs 1300 and 1300' and regarding circuit 1500 can be applied analogously to PDD 1600 and 1600'.

[0220] Figure 16AA photodetector device 1600 is shown, comprising a photosensitive region 1602 (exposed to external light during operation of the photodetector device 1600), a region 1604, and a control voltage generation circuit 1340. The photosensitive region 1602 includes a plurality of (array) PS1200s, and the region 1604 includes a plurality of reference PS1310s kept in darkness (at least during reference current measurement, optionally at all times). The control voltage generation circuit 1340 further includes a controller 1338. The controller 1338 can control the operation of an amplifier 1318, the voltage supplied to the amplifier 1318, and / or the operation of the plurality of reference PS1310s. Optionally, the controller 1338 can also control various operations of the plurality of PS1200s and / or other components of the PDD 1600. Controller 1338 can control multiple active PS 1200s and multiple reference PS 1310s to operate under the same operating conditions (e.g., bias voltage, exposure time, and readout regime). It should be noted that any function of controller 1338 can be implemented by an external controller (e.g., on another processor of an EO system on which the PDD is mounted, or by an auxiliary system such as a controller of an autonomous vehicle on which the PDD is mounted). Optionally, controller 1338 can be implemented as one or more processors, which are fabricated on the same wafer as other components of PDD 1600 (e.g., multiple PS 1200s and 1310s, amplifier 1318). Optionally, controller 1338 can be implemented as one or more processors located on a PCB connected to such a wafer. Other suitable controllers can also be implemented as controller 1338.

[0221] Figure 16BA photodetector device 1600' is shown as one of many examples of the subject matter currently disclosed. The photodetector device 1600' is similar to device 1600, but has many components arranged in a different geometry and the internal details of the various PSs are not shown. Also illustrated is a readout circuit 1610, which is used to read the multiple detection signals from the multiple PSs 1200 and provide them for further processing (e.g., noise reduction, image processing), storage, or any other purpose. For example, the readout circuit 1610 may sequentially and temporarily arrange the readout values ​​of the different PSs 1200 (possibly after some processing by one or more processors of the PDD, not shown) before providing them for further processing, storage, or any other action. Alternatively, the readout circuit 1610 may be implemented as one or more units fabricated on the same wafer as other components of the PDD 1600 (e.g., the multiple PSs 1200 and 1310, amplifier 1318). Optionally, the readout circuit 1610 can be implemented as one or more cells connected to a PCB of such a wafer. Other suitable readout circuits can also be implemented as readout circuit 1610. It should be noted that a readout circuit such as readout circuit 1610 can be implemented in any photodetector discussed in this disclosure (e.g., multiple PDDs 1300, 1700, 1800, and 1900). Prior to an optional digitization of the signal, numerous examples of analog signal processing can be performed in the PDD (e.g., via readout circuit 1610 or one or more processors of the corresponding PDD), including: gain modification (amplification), offsetting, and combining (combining multiple output signals from two or more PSs). The digitization of the readout data can be implemented on or outside the PDD.

[0222] Optionally, PDD 1600 (or any other PDD disclosed herein) may include: a sampling circuit for sampling the output voltage of amplifier 1318 and / or the control voltage V. CTRL(If different), and is used to maintain the voltage level for at least a specified shortest time period. Such a sampling circuit can be located anywhere between the output of amplifier 1318 and one or more of at least one VCCS1204 (e.g., at position 1620). Any suitable sampling circuit can be used; for example, in some cases, exemplary circuitry may include multiple "sample and hold" switches. Alternatively, the sampling circuit may be used only at certain times, while performing a direct real-time readout of the control voltage at other times. For example, using a sampling circuit may be useful when the magnitudes of numerous dark currents in the system vary slowly, or when PS1310 is only shaded for a portion of the time.

[0223] Figure 17 and Figure 18 Further examples of photodetectors according to the currently disclosed subject matter are shown. In the photodetectors described above (e.g., 1300, 1300', 1600, 1600'), a voltage-controlled current source is used for the plurality of active PS1200s and the plurality of reference PS1310s. A current source is one example of a voltage-controlled current circuit that can be used in the disclosed PDDs. Another type of voltage-controlled current circuit that can be used is a voltage-controlled current sink, the current absorbed being controlled in amplitude by a control voltage supplied to it. For example, a current sink can be used, wherein the bias voltage on the plurality of PDs (1202, 1302) is opposite in direction to the bias voltage demonstrated above. More generally, whenever a voltage-controlled current source (1204, 1304) is discussed as above, this component can be replaced by a voltage-controlled current sink (denoted as 1704 and 1714, respectively). It should be noted that using a current sink instead of a current source may require the use of different types of components or circuits in other parts of the corresponding PDD. For example, an amplifier 1318 used with multiple VCCS1204 and 1304 differs in power, size, etc., from an amplifier 1718 used with multiple voltage-controlled current sinks 1704 and 1714. To distinguish multiple PSs that include multiple voltage-controlled current sinks instead of multiple VCCSs, multiple reference numerals 1200' and 1310' correspond to the multiple PSs 1200 and 1300 discussed above.

[0224] exist Figure 17In this example, a PDD 1700 includes multiple voltage-controlled current circuits, which are multiple voltage-controlled current sinks (in both PS1200' and PS1310'), and a suitable amplifier 1718 is used instead of amplifier 1318. All variations of the multiple current sources discussed above also apply to the multiple current sinks.

[0225] exist Figure 18 In this configuration, a PDD 1800 includes two types of voltage-controlled current circuitry: voltage-controlled current sources 1204 and 1314 and voltage-controlled current sinks 1704 and 1714, and matched amplifiers 1318 and 1718. This allows the multiple PDs of the PDD 1800 to be operated, for example, with forward or reverse bias. At least one switch (or other selection mechanism) can be used to select which reference circuit is activated / deactivated, either one based on multiple VCCSs or one based on multiple voltage-controlled current sinks. Such a selection mechanism can be implemented, for example, to prevent two feedback regulators from operating "against" each other (e.g., if operating with a near-zero bias on the PD). Any options, interpretations, or variations discussed above with respect to any of the previously discussed multiple PDDs (e.g., 1300, 1300', 1600, 1600') can be applied in parallel to the multiple PDDs 1700 and 1800. Specifically, multiple PDD 1700 and 1800 may include: multiple PS1200' and / or multiple reference PS1310', similar to the discussion above (e.g., regarding...). Figure 15 , 16A and 16B).

[0226] It should be noted that in any of the photodetector devices discussed above, one or more of the aforementioned PSs (e.g., the PS of a photodetector array) may be optionally controllable to selectively function as a reference PS1310 (e.g., sometimes) or as a regular PS1200 (e.g., at other times). Such a PS may include the circuitry required to operate in both roles. For example, it can be used if the same PDA is used in different types of electro-optical systems. For example, one system may require averaging with precision between 1,000 and 4,000 reference PS1310s, while another system may require lower precision, which can be achieved by averaging between 1 and 1200 reference PS1310s. In another example, as described above, when the entire PDA is dimmed and stored in a sample-and-hold circuit, averaging based on the control voltages of some (or even all) of the PSs can be performed, and all PSs can be used to detect FOV data in one or more subsequent frames using the determined control voltages.

[0227] It should be noted that, for simplicity, in the above discussion, it is assumed that the anode side of all PDs on each PDA is connected to a known (and possibly controlled) voltage, and that the plurality of detection signals and the plurality of VCCSs are connected, and that a plurality of additional circuitry is implemented on the cathode side. It should also be noted that, alternatively, the plurality of PDs 1202 and 1302 may be connected in the opposite manner (where the readout is located on the anode side, and so on).

[0228] Referring to all the PDDs discussed above (e.g., 1300, 1600, 1700, 1800), it should be noted that the plurality of PSs, the readout circuit, the reference circuit and other aforementioned components (and any additional components that may be required) can be implemented on a single wafer or on more than one wafer, on one or more PCBs, or on another suitable type of circuit connected to the plurality of PSs, and so on.

[0229] Figure 19 A PDD 1900 is illustrated with numerous examples based on the currently disclosed subject matter. The PDD 1900 can implement any combination of features from one or more PDDs as described above, and further includes multiple additional components. For example, the PDD 1900 may include any one or more of the following components:

[0230] a. At least one light source 1902, operable to emit light onto the field of view (FOV) of the photodetector device 1900. Some of the light from the light source 1902 is reflected from objects in the FOV and captured by a plurality of photosensitive areas 1602 (which are exposed to external light during operation of the photodetector device 1900) and used to generate an image or other model of the plurality of objects. Any suitable type of light source (e.g., pulsed, continuous, modulated LEDs, lasers) can be used. Optionally, the operation of the light source 1902 can be controlled by a controller (e.g., controller 1338).

[0231] b. A physical barrier 1904 is used to keep region 1604 of the detector array in darkness. The physical barrier 1904 may be part of or outside the detector array. The physical barrier 1904 may be fixed or movable (e.g., a moving shutter). It should be noted that other types of darkening mechanisms may also be used. Optionally, the physical barrier 1904 (or other darkening mechanism) may darken different portions of the detector array at different times. Optionally, the operation of the barrier 1904, if modifiable, may be controlled by a controller (e.g., controller 1338).

[0232] c. Ignored photosensitive sites 1906. It should be noted that not all photosensitive sites (PSs) of the PDA must be used for detection (multiple PSs 1200) or as references (multiple PSs 1310). For example, some PSs may be located in an area that is neither fully dark nor fully lit, and therefore are ignored in the generation of the image (or other types of output generated in response to the multiple detection signals of the multiple PSs 1200). Optionally, the PDA 1900 may ignore different PSs at different times.

[0233] d. At least one processor 1908 for processing the plurality of detection signals output by the plurality of PS1200s. Such processing may include, for example, signal processing, image processing, spectral analysis, etc. Optionally, the processing results of the processor 1908 may be used to modify the operation of the controller 1338 (or another controller). Optionally, the controller 1338 and the processor 1908 may be implemented as a single processing unit. Optionally, the processing results of the processor 1908 may be provided to any one or more of the following: a physical memory module 1910 for various external systems (e.g., a remote server or a vehicle computer in a vehicle equipped with PDD 1900), such as via a communication module 1912; a display 1914 for displaying images or other types of results (e.g., graphics, text results from the spectrometer); another type of output interface (e.g., a speaker, not shown), and so on. It should be noted that, optionally, multiple signals from multiple PS1310s can also be processed by the processor 1908, for example, to evaluate a condition of the PDD 1900 (such as operability, temperature).

[0234] e. A memory module 1910 for storing at least one of the plurality of detection signals output by the plurality of active PSs or by the readout circuit 1610 (if different), and detection information generated by the processor 1908 by processing the plurality of detection signals.

[0235] f. Power source 1916 (e.g., battery, AC power adapter, DC power adapter). The power source can provide power to the plurality of PSs, the amplifier, or any other component of the PDD.

[0236] g. A hard casing 1918 (or any other type of structural support).

[0237] h. Optical device 1920 for directing light from light source 1902 (if implemented) to the FOV and / or for directing light from the FOV to the plurality of active PS1200s. Such optical device may include, for example, a plurality of lenses, a plurality of mirrors (fixed or movable), a plurality of prisms, a plurality of filters, and the like.

[0238] As described above, the plurality of PDDs can be used to match the control voltage, which determines the current level provided by the at least one first voltage control current circuit (VCCC) 1204 to handle differences in the operating conditions of the PDDs, which alter the variations in the plurality of levels of dark current generated by the at least one PD 1202. For example, for a PDD comprising multiple PS1200s and multiple PS1320s: when the PDD operates at a first temperature, the control voltage generation circuit 1340, in response to the dark currents of the multiple reference PDs 1302s, provides a control voltage to the voltage control current circuit to provide a current at a first level at the first temperature, thereby reducing the impact of the numerous dark currents of the active PDs 1202s on the outputs of the multiple active PS1200s; and when the PDD operates at a second temperature (higher than the first temperature), the control voltage generation circuit 1340, in response to the dark currents of the multiple reference PDs 1302s, provides a control voltage to the voltage control current circuit to provide a current at a second level, thereby reducing the impact of the dark currents of the multiple active PDs 1202s on the outputs of the multiple active PS1200s, such that the second level is greater in amplitude than the first level.

[0239] Figure 20 This is a flowchart of a method 2000 for compensating dark current in a photodetector, according to numerous examples of the subject matter of this disclosure. Method 2000 is performed in a PDD, which includes at least: (a) a plurality of active PSs, each active PS including at least one active PD; (b) at least one reference PS including a reference PD; (c) at least one first VCCC connected to one or more active PDs; (d) at least one reference VCCC connected to one or more reference PDs; and (e) a control voltage generation circuit connected to the active VCCC and the reference VCCC. For example, method 2000 can be performed in any of a plurality of PDDs 1300', 1600, 1600', 1700, and 1800 (the latter two including multiple active PSs in various implementations). It should be noted that method 2000 may include performing any of the actions or functions discussed above with respect to any of the aforementioned components of the various PDDs.

[0240] Method 2000 includes at least multiple stages (multiple stages) 2010 and 2020. Stage 2010 includes generating a control voltage based on a level of dark current in the at least one reference PD, which, when provided to the at least one reference VCCC, causes the at least one reference VCCC to generate a current that reduces the effect of the dark current of the reference PD on an output of the reference PS. Stage 2020 includes providing the control voltage to the at least one first VCCC, thereby causing the at least one first VCCC to generate a current that reduces the effect of the dark current of the plurality of active PDs on multiple outputs of the plurality of active PSs. VCCC stands for "Voltage-Controlled Current Circuit," and it can be implemented as a voltage-controlled current source or a voltage-controlled current sink.

[0241] Optionally, stage 2010 is implemented using an amplifier that is part of the control voltage generation circuit. In such a case, stage 2010 includes supplying a first input voltage to a first input of the amplifier when a second input of the amplifier is electrically connected between the reference PD and the reference voltage control current circuit. The amplifier can be used to continuously reduce a difference between an output of the reference voltage control circuit and the first input voltage, thereby generating the control voltage. Optionally, both the first VCCC(s) and the reference VCCC(s) are connected to an output of the amplifier.

[0242] In the case where the PDD includes multiple different reference PDs that generate different levels of dark current, stage 2010 may include: generating a single control voltage based on the average of the different dark currents of the multiple reference PDs.

[0243] Method 2000 may include: preventing light from a field of view from the PDD from reaching the plurality of reference PDs (e.g., using a physical barrier or deflecting optics).

[0244] Method 2000 may include: sampling multiple outputs of the plurality of active PSs after reducing the various effects of the dark current, and generating an image based on the plurality of sampled outputs.

[0245] Figure 21This is a flowchart illustrating a method for compensating dark current in a photodetector according to various examples of the subject matter of this disclosure. Method 2100 has two stages performed at different temperature regimes; a first group of stages (2110 to 2116) is performed when the PDD operates at a first temperature (T1), and a second group of stages (2120 to 2126) is performed when the PDD operates at a second temperature (T2) above the first temperature. The first and second temperatures may vary in different implementations or in different instances of method 2100. For example, the temperature difference may be at least 5°C; at least 10°C; at least 20°C; at least 40°C; at least 100°C, and so on. In particular, method 2100 may be effective over even smaller temperature differences (e.g., less than 1°C). It should be noted that each of the first and second temperatures may be implemented as a temperature range (e.g., spanning 0.1°C; 1°C; 5°C or higher). Any temperature within the second temperature range is higher than any temperature within the first temperature range (e.g., according to the aforementioned ranges). Method 2100 may optionally be performed in any of the PDDs discussed above (1300, 1600, etc.). It should be noted that method 1020 may include performing any of the actions or functions discussed above with respect to any component of the various aforementioned PDDs, and the PDD of method 1020 may include any combination of one or more of the components discussed above with respect to any of the aforementioned PDDs.

[0246] Referring to the multiple stages performed when the PDD operates at the first temperature (which may be a first temperature range): Stage 2110 includes determining a first control voltage based on the dark current of at least one reference PD of the PDD. Stage 2112 includes providing the first control voltage to a first VCCC, the first VCCC being coupled to at least one active PD of an active PS of the PDD, thereby causing the first VCCC to impose a first dark-current countering current in the active PS. Step 2114 includes generating a first detection current by the active PD in response to: (a) light from the active PD impacting an object in a field of view of the PDD, and (b) the dark current generated by the active PD. Stage 2116 includes outputting a first detection signal from the active PS in response to the first detection current and the first dark-current countering current, the first detection signal being smaller in amplitude than the first detection current, thereby compensating for the effect of the dark current on the first detection signal. Method 2100 may further include an optional stage 2118 for generating at least one first image of a field of view (FOV) of the PDD based on a plurality of first detection signals from a plurality of PSs (and optionally all) of the PDD. Stage 2118 may be performed when the PDD is at the first temperature or in a subsequent stage.

[0247] Referring to the multiple stages performed when the PDD operates in the second temperature (which may be a second temperature range): Stage 2120 includes determining a second control voltage based on the dark current of at least one reference PD of the PDD. Step 2122 includes providing the second control voltage to the first VCCC, thereby causing the first VCCC to apply a second dark current resisting current in the active PS; Stage 2124 includes generating a second detection current by the active PD in response to: (a) a light impact from the active PD originating from the object, and (b) the dark current generated by the active PD. Stage 2126 includes outputting a second detection signal with an amplitude smaller than the second detection current by the active PS in response to the second detection current and the second dark current resisting current, thereby compensating for the effect of the dark current on the second detection signal. The amplitude of the second dark current resisting current is greater than the amplitude of the first dark current resisting current, and may be by any ratio greater than one. For example, the ratio may be a factor of at least two times or significantly higher (e.g., on the order of one, two, three (or more) amplitudes). Method 2100 may further include an optional stage 2128 for generating at least one second image of a field of view (FOV) of the PDD based on a plurality of second detection signals (and optionally all) from the PDD. Stage 2128 may be performed when the PDD is at the second temperature or in a subsequent stage.

[0248] Optionally, a first level of radiation (L1) striking the active PD from the object during a first time (t1) when the first dark current resisting current is generated is substantially equal to a second level of radiation (L2) striking the active PD from the object during a second time (t2) when the second dark current resisting current is generated, wherein the amplitude of the second detection signal is substantially equal to the amplitude of the first detection signal. It should be noted that, optionally, the PDD according to this disclosure can be used to detect multiple signal levels significantly lower than the dark current levels generated by its PD at certain operating temperatures (e.g., by one, two, or more orders of magnitude). Therefore, method 2100 can be used to emit multiple output signals of similar levels at two different temperatures, wherein the multiple dark currents are two or more orders of magnitude larger than the multiple detection signals and are significantly different from each other (e.g., by a factor of ×2, ×10).

[0249] Optionally, the determination of the first control voltage and the determination of the second control voltage are performed by a control voltage generation circuit, the control voltage generation circuit including at least one amplifier having an input electrically connected between the reference PD and a reference voltage control current circuit coupled to the reference PD.

[0250] Optionally, method 2100 may further include: supplying a first input voltage to another input of the amplifier, the level of the first input voltage being determined to correspond to a bias voltage on the active PD. Optionally, method 2100 may include: supplying the first input voltage such that a bias voltage on the reference PD is substantially the same as a bias voltage on the active PD. Optionally, method 2100 may include: determining a first control voltage and a second control voltage based on the different dark currents of the plurality of reference PDs of the PDD when the plurality of active PDs have a plurality of different dark currents, wherein the provision of the first control voltage includes providing the same first control voltage to a plurality of first voltage control current circuits, each first voltage control current circuit being coupled to at least one of the plurality of active PDs of the PDD having different dark currents, wherein the provision of the second control voltage includes providing the same second control voltage to the plurality of first voltage control current circuits.

[0251] Optionally, multiple different active power supplies (PDs) simultaneously generate multiple different levels of dark current, and multiple different reference power supplies (PDs) simultaneously generate multiple different levels of dark current, and the control voltage generation circuit provides the same control voltage to the different active power supplies based on the average of the multiple different dark currents of the second power supply (PD). Optionally, method 2100 may include: using dedicated optics to guide light from the field of view to multiple active power supplies (PDs) of the PDD; and preventing light from the field of view from reaching multiple reference power supplies (PDs) of the PDD.

[0252] Figure 22This is a flowchart illustrating a method 2200 for testing a photodetector according to various examples of the subject matter of this disclosure. For example, the test can be performed using any of the aforementioned PDDs. That is, the same circuitry and architecture described above, which can be used to reduce the effects of dark current, can be used for additional purposes to test multiple detection paths of multiple different PSs in real time. Optionally, the test can be performed while the PDD is in an operating mode (i.e., not in a test mode). In some implementations, some PSs can be tested while exposed to ambient light from the FOV, even when multiple other PSs of the same PDD capture an actual image of the FOV (with or without dark current compensation). Nevertheless, it should be noted that method 2200 can also optionally be implemented in multiple other types of PDDs. It should also be noted that method 2200 can also optionally be implemented using multiple circuitry or architectures similar to those discussed above with respect to multiple PDDs, but when the multiple PDs are not characterized by high dark current and dark current reduction is not required or performed. Method 2200 is described as being applied to a single PS, but it can be applied to some or all of the PSs in a PDD.

[0253] Step 2210 of method 2200 includes: providing a first voltage to a first input of an amplifier in a control voltage generation circuit, wherein a second input of the amplifier is connected to a reference PD and a second current circuit, the second current circuit supplying current, the current being dominated at a level in response to an output voltage of the amplifier; thereby causing the amplifier to generate a first control voltage for a first current circuit of a PS for the PDD. Referring to the numerous examples illustrated with respect to the preceding figures, the amplifier may be amplifier 1318 or amplifier 1718, and the PS may be PS1310 or PS1310'. Several examples of providing multiple first voltages to the first input are discussed below.

[0254] Phase 2220 of method 2200 includes reading a first output signal of the PS generated by the PS in response to a current generated by the first current circuit and a current generated by a PD of the PS.

[0255] Step 2230 of method 2200 includes providing a second voltage, different from the first input, to the first input of the amplifier, thereby causing the amplifier to generate a second control voltage for the first current circuit. Numerous examples of such second voltages can be discussed below.

[0256] Phase 2240 of method 2200 includes reading a second output signal of the PS generated by the PS in response to a current generated by the first current circuit and a current generated by a PD of the PS.

[0257] Phase 2250 of method 2200 includes determining a defect state of a detection path of the PDD based on the first output signal and the second output signal, the detection path including the PS and a readout circuit associated with the PS. Numerous examples of which types of defects can be detected when using multiple different combinations of the first and second voltages are discussed below.

[0258] A first example involves using at least one of the first voltage and the second voltage to attempt to saturate the PS (e.g., by providing a very high current to the capacitor of the PS through the VCCS, regardless of the actual detection level). Failure to saturate the PS (e.g., receiving a detection signal that is not white, but may be completely black or halftone) indicates a problem with the associated PS or other components in its readout path (e.g., PS amplifier, sampler, analog-to-digital converter). In such a case, the first voltage (e.g.) causes the amplifier to generate a control voltage that causes the first current circuit to saturate the PS. In such a case, at stage 2250, the determination of the defective state may include: determining the detection path where the PS is malfunctioning in response to determining that the first output signal is not saturated. In such a case, the second voltage may be a voltage that does not cause the PS to saturate (e.g., it causes the VCCS not to emit current, only compensating for the dark current to prevent current from being collected by the capacitor). Testing whether a PS detection path can saturate can be performed in real time.

[0259] When attempting to saturate one or more PSs to test the PDD, method 2200 may include: reading the first output signal during a first detection frame of the PDD when the PS is exposed to ambient light, wherein the decision of the fault state is performed after a previous determination that the detection path is operable, in response to reading a saturated output signal in a second detection frame earlier than the first frame. For example: in an ongoing operation of the PDD (e.g., while capturing a video), if a saturation attempt fails, a PS may be determined to be defective or unusable after it succeeded at a previous time in the same operation. The test may be performed in a testing frame that is not part of the video, or for individual PSs whose saturated output is ignored (e.g., the pixel colors corresponding to these PSs can be obtained from multiple adjacent pixels of the frame on which they are tested), treating these PSs as spans unusable for this frame.

[0260] A second example involves using at least one of the first and second voltages to attempt to consume the PS (e.g., by providing a very high opposite current to the capacitor of the PS via the VCCS, regardless of the actual detection level). Failure to consume the PS (e.g., receiving a detection signal that is not black, but may be full white or halftone) indicates a problem with the relevant PS or other components in its readout path. In such a case, the second voltage (e.g.) causes the amplifier to generate a second control voltage, which causes the first current circuit to consume a detection signal caused by field light impacting the PS. In such a case, at stage 2250, the determination of the defective state may include determining that the detection path is malfunctioning in response to determining that the second output signal is not consumed. In such a case, the first voltage may be a voltage that does not cause the PS to saturate (e.g., it would cause the VCCS to not emit current, only compensating for the dark current, thereby saturating the capacitor). Testing whether a PS detection path can be consumed (e.g., without dimming the individual PSs) can be performed in real time.

[0261] When attempting to consume one or more PSs to test the PDD, method 2200 may include reading the second output signal in a third detection frame of the PDD when the PS is exposed to ambient light, wherein the decision of the fault state is performed after a previous determination that the detection path is operable, in response to reading a consumed output signal in a fourth detection frame earlier than the third frame.

[0262] Method 2200, another example of testing a PS by supplying multiple control voltages, includes supplying two or more voltages. For example, three or more different voltages may be provided to the first input of the amplifier at different times (e.g., in different frames). In such a case, stage 2250 may include determining the defect state of the detection path of the PDD based on the first output signal, the second output signal, and at least one other output signal corresponding to the third or more voltages supplied to the first input of the amplifier. For example, at different times (e.g., monotonically, where each voltage is greater than a previous voltage), three, four, or more different voltages may be supplied to the first input of the amplifier, and the multiple output signals of the same PS corresponding to the different voltages may be tested to correspond to the multiple supplied voltages (e.g., the multiple output signals also monotonically increase in amplitude).

[0263] An example of using method 2200 to test a portion (or even all) of the PDD includes reading at least two output signals from each of a plurality of PSs of the PDD to determine an operating state for at least one first detection path based on at least two output signals from at least one PS associated with the corresponding first detection path in response to at least two different voltages supplied to the amplifier of the corresponding PS, and determining a fault state for at least one second detection path based on the at least two output signals from at least one other PS associated with the corresponding second detection path.

[0264] Optionally, when the PDD is shielded from ambient light, and / or when specified lighting (such as a known amplitude, dedicated lighting, or the like) is used, method 2200 may be performed in conjunction with multiple specified test targets (such as black targets, white targets), but is not required to do so.

[0265] Optionally, stage 2250 can be replaced by determining an operational state for the detection path. For example, this can be used to calibrate multiple different PSs of the PDD to the same level. For example, when the PDD is dimmed and there is no dedicated target or dedicated lighting, the same voltage can be supplied to the VCCSs of different PSs. Different output signals of different PSs can be compared with each other (at one or more different voltages supplied to the first input of the amplifier). Based on the comparison, multiple correction values ​​can be assigned to different PS detection paths so that they will provide a similar output signal (simulated by the current contained in the multiple VCCSs of the different PSs) for similar lighting levels. For example, it can be determined that the output of PS A should be multiplied by 1.1 to output a calibrated output signal to PS B. For example, it can be determined that an incremental signal ΔS should be added to the output of PS C to output a calibrated output signal to PSD. Nonlinear correction can also be implemented.

[0266] Figure 23 An EO system 2300, according to numerous examples of the currently disclosed subject matter, is illustrated. The EO system 2300 includes at least one PDA 2302 and at least one processor 2304 operable to process multiple detection signals from multiple PS 2306 of the PDA. The EO system 2300 can be any type of EO system using a PDA for detection, such as a camera, spectrometer, LiDAR, and the like.

[0267] The at least one processor 2304 is operable and configured to process multiple detection signals output by multiple PS2306 of at least one PDA 2302. Such processing may include, for example, signal processing, image processing, spectral analysis, etc. Optionally, the processing results of the processor 2304 may be provided to any one or more of the following: a tangible memory module 2308 (for storage or later retrieval), a display 2312 for displaying an image or other type of result (e.g., graph, text results from a spectrometer) for an external system (e.g., a remote server or a vehicle computer in a vehicle equipped with the EO system 2300), such as via a communication module 2310, another type of output interface (e.g., a speaker, not shown), and so on.

[0268] The EO system 2300 may include a controller 2314 that controls multiple operating parameters of the EO system 2300 (e.g., PDA 2302 and an optional light source 2316). Specifically, the controller 2314 may be configured to set (or otherwise change) the multiple frame exposure times used by the EO system 2300 to capture different frames. Optionally, multiple processing results of multiple light detection signals by the processor 2304 may be used to modify the operation of the controller 2314. Optionally, the controller 2314 and the processor 2304 may be implemented as a single processing unit.

[0269] The EO system 2300 may include at least one light source 2316 operable to emit light onto the field of view (FOV) of the EO system 2300. Some of the light from the light source 2316 is reflected from objects in the FOV and captured by PS 2306 (at least those PS located in a photosensitive area exposed to external light during multiple frame exposure times of the EO system 2300). Detecting light from multiple objects in the FOV (whether reflected light from the light source, reflected light from other light sources, or radiated light) is used to generate an image or other model (e.g., a three-dimensional depth map) of the multiple objects. Any suitable type of light source can be used (e.g., pulsed, continuous, modulated, LED, laser). Optionally, the operation of the light source 2316 may be controlled by a controller (e.g., controller 2314).

[0270] The EO system 2300 may include a readout circuit 2318 for reading out multiple electrical detection signals from multiple different PS 2306s. Optionally, the readout circuit 2318 may process the multiple electrical detection signals before providing them to the processor 2304. Such preprocessing may include, for example, amplification, sampling, weighting, noise reduction, correction, digitization, capping, level adjustments, dark current compensation, and the like.

[0271] In addition, the EO system 2300 may include: multiple additional components, such as (but not limited to) one or more of the following optional components:

[0272] a. Memory module 2308 for storing at least one of a plurality of detection signals output by the plurality of PS2306 or by the readout circuit 2318 (if different), and detection information generated by the processor 2304 by processing the plurality of detection signals.

[0273] b. A power source 2320, such as a battery, an AC power adapter, a DC power adapter, or the like. The power source 2320 can provide power to the PDA, the readout circuit 2318, or any other component of the EO system 2300.

[0274] c. A rigid shell 2322 (or any other type of structural support).

[0275] d. Optical device 2324 for directing light from light source 2316 (if implemented) to the FOV and / or for directing light from the FOV to PDA 2300. Such optical device may include, for example, numerous lenses, numerous mirrors (fixed or movable), numerous prisms, numerous filters, and the like.

[0276] Optionally, the PDA 2302 may be characterized by a relatively high dark current (e.g., a result of the type and characteristics of its PD). Due to this high level of dark current, the multiple capacitors of the individual PS2306 that collect the detection charge may be saturated (partially or completely) by the dark current, resulting in little or no dynamic range for detecting ambient light (from FOV). Even if the readout circuitry system 2318 or processor 2304 (or any other component of system 2300) subtracts multiple dark current levels from the detection signal (e.g., normalizes the detection data), there is still a lack of dynamic range for detection, meaning that the resulting detection signal from the individual PS2306 is too saturated to be meaningfully used for detecting multiple ambient light levels. Since the dark current from the PD of the individual PS2306 accumulates in the capacitors (whether actual capacitors of the other components of the multiple PSs or parasitic or residual capacitors) throughout the entire duration of the frame exposure time (FET), multiple different PS2306 with different capacitances may be rendered unusable in multiple different FETs.

[0277] Figure 24An example of a method 2400 for generating image information based on data from a PDA, according to the currently disclosed subject matter, is illustrated. Referring to the numerous examples illustrated with reference to the preceding figures, method 2400 can be executed by an EO system 2300 (e.g., by a processor 2304, controller 2314, etc.). In such a case, the PDA of method 2400 may optionally be PDA 2302. Other relevant components discussed in method 2400 may be the various corresponding components of the EO system 2300. Method 2400 includes changing a frame FET (FET), in which the PDA collects a plurality of charges from its PDs. Such collected charges may be due to the photoelectric response to light impacting the plurality of PDs and multiple inherent sources within the detection system, such as those due to the dark current of the PDs. The impacting light may arrive from, for example, a camera mounted on the PDA or a field of view (FOV) of another EO system. The FET can be controlled electronically, mechanically, or in any combination thereof, by controlling the flash illumination duration, etc.

[0278] It should be noted that the FET can be a single FET, which is the sum of multiple different durations, in which the PDA collects charge due to photoelectric activity in multiple PSs of the PDA. A single FET is used where the charge collected over the different durations is summed to provide a single output signal. Such a single FET can be used, for example, with pulsed illumination or with active illumination, in which the collection is suspended for a short time (e.g., to avoid saturation by a bright reflection in the FOV). It should be noted that, optionally, a single FET can be used in some frames, while the entire FET can be used in other frames.

[0279] Phase 2402 of method 2400 includes receiving first frame information. For each of a plurality of PSs in a PDA, the first frame information includes a first frame detection level, which indicates an intensity of light detected by the respective PS in a first FET. Receiving the first frame information may include receiving multiple readout signals from all the PSs of the PDA, but this is not mandatory. For example, some PSs may be defective and unable to provide a signal. For example, a region of interest (ROI) may be defined for the frame, indicating that data is collected only from a portion of the frame, and so on.

[0280] The frame information can be provided in any format, such as a detection level (or multiple levels) for each PS (e.g., between 0 and 1024, three RGB values, each between 0 and 255, etc.), scalar, vector, or any other format. Optionally, the frame information (for the first frame or many subsequent frames) may optionally indicate multiple detection signals indirectly (e.g., information about the detection level of a given PS may be given relative to the level of an adjacent PS or relative to the level of the same PS in a previous frame). The frame information may also include additional information (e.g., sequence number, timestamp, operating conditions), some of which may be used in subsequent steps of method 2400. The first frame information (and the frame information for many subsequent frames received in later stages of method 2400) may be received directly from the PDA or from one or more intermediate units (e.g., an intermediate processor, a memory unit, a data aggregator, etc.). The first frame information (and the frame information for later frames received in a later stage of method 2400) may include the raw data acquired by each PS, but may also include preprocessed data (e.g., data that has undergone weighting, denoising, correction, digitization, upper limit setting, level adjustment, and the like).

[0281] Phase 2404 includes identifying at least two types of PSs among the plurality of PSs of the PDD based on the first FET:

[0282] a. A group of usable PSs for the first frame (referred to as the "first group of usable PSs") includes at least a first PS, a second PS, and a third PS of the plurality of PSs of the PDA.

[0283] b. A group of unusable PSs used for the first frame (referred to as the "first group of unusable PSs") includes at least a fourth PS among the plurality of PSs of the PDA.

[0284] The identification in stage 2404 can be implemented in different ways and may optionally include (explicitly or implicitly) identifying each of the plurality of PSs as belonging to one of the at least two groups mentioned above. Optionally, each PS of the PDA (or each PS of a predetermined subgroup thereof, such as all PSs of an ROI) may be assigned to one of two plurality of groups relative to the first frame, the first available PS group or the first unavailable PS group. However, this is not necessarily required, and some PSs may not be assigned for some frames, or may be assigned to other plurality of groups (e.g., the availability of the plurality of PSs is determined based on many parameters other than the FET of the corresponding first frame, such as based on the collected data). Optionally, the identification in stage 2404 may include: determining which PSs conform to one of the first plurality of PSs, and automatically considering the remaining PSs of the PDA (or a predetermined subgroup thereof, such as an ROI) as belonging to the other plurality of PSs of the two groups.

[0285] It should be noted that the identification in stage 2404 (and stages 2412 and 2402) does not necessarily reflect an actual availability state of the individual PSs (which, in some implementations, does indeed reflect such actual availability states). For example, a PS included in the first unavailable PS group may actually be available under the multiple conditions of the first frame, while another PS included in the first available PS group may actually be unavailable under the multiple conditions of the first frame. The identification in stage 2404 is an estimation or assessment of the availability of the multiple PSs of the PDA, not a test of the individual PSs. It should also be noted that the availability of the multiple PSs may also be estimated in stage 2404 based on other factors. For example, a pre-existing list of defective PSs may be used to exclude such PSs from being considered available.

[0286] The identification in stage 2404 (and stages 2412 and 2420) may include: identifying at least one of the plurality of unavailable PS groups (and / or at least one of the plurality of available PS groups) based on a sum of the durations during which the plurality of sampled PSs of the composite FET including the PDD are photosensitive, and excluding a plurality of intermediate times between the plurality of durations during which the plurality of sampled PSs of the PDD are not photosensitive.

[0287] The identification of multiple groups of available and unavailable PSs (in stages 2404, 2412, and / or 2420) may be based in part on a temperature assessment. Optionally, method 2400 may include processing one or more frames (particularly multiple previous frames or the current frame) to determine a temperature assessment (e.g., by assessing the dark current level in a dark frame or in multiple darkened PSs not mapped to the FOV). Then, method 2400 may include using the temperature assessment to identify a group of available PSs and a group of unavailable PSs for a later frame, which affects the generation of the corresponding image. The temperature assessment may be used to assess how quickly the dark current saturates over the duration of the associated FET, saturating the dynamic range of a given PS. Optionally, the temperature assessment may be used to utilize a parameter of an availability model of the PS (e.g., one generated in method 2500).

[0288] The timing of execution of stage 2404 can be varied relative to the timing of execution of stage 2402. For example, stage 2404 may optionally be executed before, simultaneously with, partially simultaneously with, or after the execution of stage 2402. Referring to the example in the accompanying drawings, stage 2404 may optionally be executed by processor 2304 and / or controller 2314. Numerous examples of various methods for executing the identification of stage 2404 are discussed with respect to method 1100.

[0289] Step 2406 includes: disregarding the plurality of first frame detection levels of the first unavailable PS group, generating a first image based on the plurality of first frame detection levels of the first available PS group. The generation of the first image can be implemented using any suitable method and can optionally be based on additional information (e.g., data received from an active lighting unit, or, if used, data from numerous additional sensors such as numerous humidity sensors). Referring to the numerous examples illustrated with respect to the preceding figures, it should be noted that step 2406 can optionally be implemented by processor 2304. It should be noted that the generation can include: processing multiple different stages of the plurality of signals (e.g., weighting, noise reduction, correction, digitization, setting upper limits, level adjustment, and so on).

[0290] For the first unusable PS group, it should be noted that since the detection data of those PSs are ignored in the generation of the first image, multiple replacement values ​​can be calculated in any suitable manner (if desired). Such multiple replacement values ​​can be calculated, for example: based on multiple first-frame detection levels of multiple neighboring PSs, based on multiple earlier detection levels of multiple earlier frames, based on the same PS (e.g., if available in a previous frame) or one or more neighboring PSs (e.g., based on kinematic analysis of the scene). For example: a Wiener filter, local mean algorithms, non-local mean algorithms, and the like can be used. Referring to the generation of multiple images based on the PDA data, optionally, any one or more such images generated (e.g., the first image, the second image, and the third image) may include: calculating a replacement value for at least one pixel associated with a PS that is identified as unusable in the corresponding image based on the detection levels of at least one other neighboring PS identified as usable in the corresponding image. When using non-binary availability assessment (and the identification described in stages 2404, 2412 and / or 2420 includes identifying at least one PS as belonging to a third group of partially available PSs), the detection signal of each such PS is partially identified as available and can be combined or averaged with multiple detection signals of multiple adjacent PSs and / or multiple other readings of multiple identical PSs at other times when they are available (or partially available).

[0291] Optionally, the generation of the first image (and subsequently the generation of the second and third images) may further include ignoring multiple outputs of multiple PSs that are determined to be defective, ineffective, or unusable for any other reason, or detection paths that are determined to have a defective, ineffective, or unusable path. An example of an additional method for detecting defects in multiple PSs and / or multiple associated detection paths is discussed with respect to method 2200, which may be combined with method 2400. The outputs of method 2200 may be used in generation stages 2406, 2414, and 2422. In such a case, method 2200 may be executed periodically and provide multiple outputs for generating the multiple images, or may be specifically triggered according to method 2400 for the generation of multiple images.

[0292] Optionally, the generation of the first image (and the second and third images, to be continued) may include: when a PS is determined to be available, calculating a replacement value for at least one pixel associated with the PS based on a measured detection level of the PS, wherein the PS is identified as unavailable for the corresponding image. Such information may be used together with information from multiple adjacent PSs, or independently of them. Using multiple detection levels of a PS from other times may include, for example, considering multiple detection levels from multiple previous frames (e.g., for multiple still scenes), or using detection information from another snapshot of a series of image acquisitions used to generate a composite image, such as a high dynamic range image (HDRI) or a multi-wavelength composite image (where several shots are taken using different spectral filters and then combined into a single image).

[0293] It should be noted that in the first image (and in any other frame generated based on the detection data from the PDA), a single pixel can be based on the detection data from a single PS or a combination of multiple PSs; similarly, the information from a single PS can be used to determine the pixel color of one or more pixels in the image. For example, a field of view of Θ multiplied by Φ degrees can be covered by multiple X multiplied by Y PSs and can be converted into N multiplied by N pixels in the image. The pixel value of one of these M×N pixels can be calculated as Pixel-Value(i,j) = Σ(a) for one or more PSs. p,s ·DL p,s The sum of ) where DL p,s The detection level is used for PS(p,s) of the frame, and a p,s It is an average coefficient of the specific pixel (i,j).

[0294] After stage 2406, the first image can then be provided to an external system (e.g., a screen monitor, a storage unit, a communication system, an image processing computer). The first image can then be processed using the one or more image processing algorithms. After stage 2406, the first image can then be processed in other ways as desired.

[0295] For a number of frames captured by the photodetector sensor, whether or not they are multiple consecutive frames, stages 2402 to 2406 can be repeated several times. It should be noted that in some implementations, such as if high dynamic range (HDR) imaging is implemented, the first image can be generated based on multiple detection levels across several frames. In other implementations, the first image is generated using multiple first-frame detection levels for a single frame. Multiple instances of stages 2402 and 2406 can follow a single instance of stage 2404 (e.g., if the same FET is used for several frames).

[0296] Phase 2408 is executed after receiving the first frame information and includes: determining a second FET, the second FET being longer than the first FET. The determination of the second FET includes determining a duration (e.g., in milliseconds, its fractions, or multiples thereof) of the exposure of a plurality of associated PDs. Phase 2408 may also include: determining a plurality of additional timing parameters (e.g., the start time of the exposure), but this is not mandatory. The second FET, being longer than the first FET, can be selected for any reason. Such a reason can include, for example, any one or more of the following: the overall light intensity in the FOV, the light intensity in the fractions of the FOV, the use of bracketing techniques, the use of high dynamic range photography techniques, aperture changes, and so on. The second FET can be longer than the first FET by any ratio, whether a relatively low value (e.g., ×1.1 times, ×1.5 times), a value several times greater (e.g., ×2, ×5), or a higher value (e.g., ×20, ×100, ×5,000). Referring to the various examples in the accompanying drawings, stage 2408 may optionally be executed by controller 2314 and / or processor 2304. Optionally, an external system may determine or influence the settings of the first FET through EO system 2300 (e.g., a control system of a vehicle on which EO system 2300 is installed).

[0297] It should be noted that, optionally, at least one of stages 2408 and 2416 can be replaced by deciding on a new FET (the second FET and / or the third FET, respectively) in conjunction with such an external entity. Such an external entity can be, for example, an external controller, an external processor, or an external system. It should be noted that, optionally, at least one of stages 2408 and 2416 can be replaced by receiving an indication from an external entity for a new FET (the second FET and / or the third FET, respectively). The indication for the FET can be explicit (e.g., duration in milliseconds) or implicit (e.g., an indication of changes in aperture opening and / or exposure value (EV) corresponding to the FET, an indication of flash duration). It should be noted that, optionally, at least one of stages 2408 and 2416 can be replaced by receiving an indication from an external entity for the expected dark current (or at least a portion of the dark current being transferred to the capacitor of the PS, for example, if multiple dark current mitigation strategies are implemented).

[0298] Phase 2410 includes receiving second frame information. The second frame information includes a second frame detection level for each of the plurality of PSs of the PDA, the second frame detection level indicating an intensity of light detected by the corresponding PS in the second FET. It should be noted that the second frame (in which the detection data for the second frame information is collected) may directly follow the first frame, but this is not mandatory. The plurality of FETs in any one of the one or more intermediate frames (if any) between the first and second frames may be equal to the first FET, the second FET, or any other FET (longer or shorter). Referring to the example in the accompanying drawings, phase 2410 may optionally be executed by processor 2304 (e.g., via readout circuitry 2318).

[0299] Phase 2412 includes identifying at least two types of PSs of the PDA from a plurality of PSs of the PDD based on the second FET:

[0300] a. A group of usable PSs used for the second frame (referred to as the "second group of usable PSs") includes the first PS.

[0301] b. A group of unusable PSs used for the second frame (referred to as “a second group of unusable PSs”) includes the second PS, the third PS, and the fourth PS.

[0302] That is, because the FET of the second frame is longer, the second and third PSs identified in stage 2404 as belonging to the first group of available PSs (i.e., the aforementioned group of available PSs for the first frame) are identified in stage 2412 as belonging to the second group of unavailable PSs (i.e., the aforementioned group of unavailable PSs for the second frame). The identification in stage 2412 can be implemented in different ways, such as any one or more of those discussed above regarding stage 2404. For various reasons, multiple PSs considered usable for the shorter FET may be considered unusable for the longer FET in stage 2412. For example, if such a PS has a charge storage capacity (e.g., capacitance) lower than the average charge storage capacity of multiple PSs in the PDA, then the charge storage capacity of these PSs can be considered insufficient for the detection signal and the accumulated dark current over a longer integration time. If the dark current level is maintained (e.g., the temperature and bias on the PD remain constant), any PS that cannot be presented in the first FET because it cannot maintain sufficient dynamic range will also be identified as unusable for the longer second FET.

[0303] Phase 2412 is executed after phase 2408 (because it is based on the multiple outputs of phase 2408). The timing of the execution of phase 2412 can vary relative to the timing of the execution of phase 2410. For example, phase 2412 may optionally be executed before, simultaneously with, partially simultaneously with, or after the execution of phase 2410. Referring to the example in the accompanying drawings, phase 2412 may optionally be executed by processor 2304. Numerous examples of various methods for executing the identification of phase 2412 are discussed with respect to method 2500.

[0304] Phase 2414 includes: ignoring the multiple second-frame detection levels of the second unavailable PS group, generating a second image based on the multiple second-frame detection levels of the second available PS group. Importantly, phase 2414 includes generating the second image while ignoring the multiple outputs (multiple detection levels) of at least two PSs used to generate the first image. Based on the FETs of the first frame, these at least two PSs are identified as available and as usable for generating the first image (i.e., at least the second and third PSs). The generation of the second image can be implemented using any suitable method, including any methods, techniques, and variations discussed above with respect to the generation of the first image. Regarding the second unavailable PS group, it should be noted that since the detection data of those PSs are ignored in the generation of the second image, multiple replacement values ​​can be calculated in any suitable manner (if needed). After phase 2414, the second image can then be provided to an external system (e.g., a screen monitor, a storage unit, a communication system, an image processing computer) and then processed using one or more image processing algorithms, or further processing can be performed as needed.

[0305] For a number of frames captured by the photodetector sensor, whether or not they are multiple consecutive frames, stages 2410 to 2414 can be repeated multiple times. It should be noted that in some implementations, for example, if high dynamic range (HDR) imaging is implemented, the second image can be generated based on multiple detection levels across several frames. In other implementations, the second image is generated using multiple second-frame detection levels across a single frame. Multiple instances of stages 2410 and 2414 can follow a single instance of stage 2412 (e.g., if the same second FET is used for several frames).

[0306] Step 2416 is executed upon receiving the second frame information and includes: determining a third FET, which is longer than the first FET and shorter than the second FET. The determination of the third FET includes: determining a duration (e.g., in milliseconds, a fraction thereof, or a multiple thereof) of the exposure for the plurality of associated PDs. Step 2416 may also include: determining multiple additional timing parameters (e.g., the start time of the exposure), but this is not mandatory. The third FET can be selected for any reason, such as the reasons discussed above regarding the determination of the second FET in step 2408. The third FET can be longer than the first FET by any ratio, whether a relatively low value (e.g., ×1.1 times, ×1.5 times), a value several times greater (e.g., ×2, ×5), or any higher value (e.g., ×20, ×100, ×5,000). The third FET can be shorter than the second FET by any ratio, whether it is a relatively low value (e.g., ×1.1 times, ×1.5 times), several times (e.g., ×2, ×5), or any higher value (e.g., ×20, ×100, ×5,000). Referring to the example in the accompanying drawings, stage 2416 may optionally be executed by controller 2314 and / or processor 2304. Optionally, an external system may determine the settings of the first FET or influence the FET through EO system 2300.

[0307] Phase 2420 of method 2400 includes receiving third frame information. The third frame information includes a third frame detection level for each of the plurality of PSs of the PDA, the third frame detection level indicating an intensity of light detected by the corresponding PS in the third FET. It should be noted that the third frame (in which the detection data for the third frame information is collected) may directly follow the second frame, but this is not mandatory. The plurality of FETs in any one of the one or more intermediate frames (if any) between the second frame and the third frame may be equal to the second FET, the third FET, or any other FET (longer or shorter). Referring to the example in the accompanying drawings, phase 2420 may optionally be performed by processor 2304 (e.g., via readout circuitry 2318).

[0308] Step 2420 includes identifying at least two types of PSs of the PDA from a plurality of PSs of the PDD based on the third FET:

[0309] a. A group of usable PSs for the third frame (referred to as the "third group of usable PSs") includes the first PS and the second PS.

[0310] b. A group of unusable PSs used for the third frame (referred to as “a third group of unusable PSs”) includes the third PS and the fourth PS.

[0311] That is, because the third frame is longer than the FET of the first frame, the second PS, which was identified as belonging to the first available PS group (i.e., the aforementioned available PS group used for the first frame) in stage 2404, is identified as belonging to the third unavailable PS group (i.e., the aforementioned unavailable PS group used for the third frame) in stage 2420. Similarly, because the third frame is longer than the FET of the second frame, the third PS, which was identified as belonging to the second unavailable PS group (i.e., the aforementioned unavailable PS group used for the second frame) in stage 2412, is identified as belonging to the third available PS group (i.e., the aforementioned available PS group used for the third frame) in stage 2420.

[0312] The identification described in stage 2420 can be implemented in different ways, such as any or more of those discussed above with respect to stage 2404. For various reasons, such as those discussed above with respect to stage 2412, multiple PSs considered usable for a shorter FET may be considered unusable for a longer FET in stage 2420. For various reasons, multiple PSs considered unusable for a longer FET may be considered usable for the shorter FET in stage 2420. For example, if the charge storage capacity (e.g., capacitance) of such multiple PSs is greater than the charge storage capacity of some PSs in the second unusable PS group, then the charge storage capacity of those different PSs can be considered sufficient for the detection signal and the accumulated dark current in a shorter integration time than that of the second FET.

[0313] Phase 2420 is executed after phase 2416 (because it is based on the multiple outputs of phase 2416). The timing of the execution of phase 2420 can vary relative to the timing of the execution of phase 2416. For example, phase 2420 may optionally be executed before, simultaneously with, partially simultaneously with, or after the execution of phase 2416. Referring to the example in the accompanying drawings, phase 2420 may optionally be executed by processor 2304 and / or controller 2314. Numerous examples of various methods for identifying the execution of phase 2420 are discussed with respect to method 1100.

[0314] Phase 2422 includes: ignoring the multiple third-frame detection levels of the third unavailable PS group, generating a third image based on the multiple third-frame detection levels of the third available PS group. Importantly, phase 2422 includes generating the third image while ignoring the multiple outputs (detection levels) of at least one PS used in the generation of the first image (e.g., the second PS), and utilizing the multiple outputs of at least one PS in the generation of the second image (e.g., the third PS). The generation of the third image can be implemented using any suitable method, including any methods, techniques, and variations discussed above regarding the generation of the first image. Regarding the third unavailable PS group, it should be noted that since the detection data of these PSs are ignored in the generation of the third image, multiple replacement values ​​can be calculated in any suitable manner (if needed). After phase 2422, the third image can be provided to an external system (e.g., a screen monitor, a storage unit, a communication system, an image processing computer). After stage 2422, the third image may be processed using one or more image processing algorithms. After stage 2422, the third image may then be processed in other ways as desired.

[0315] Optionally, the generation of one or more images (e.g., the first image, the second image, the third image) in method 2400 may be based on a prior stage of evaluating the dark current accumulation of at least one PS for the corresponding image, such as at least based on the corresponding FET, electrical measurements in the captured or proximity light signal, and the like. For example, such measurement may include measuring the dark current (or another indicative measurement) on a reference PS kept in darkness. The generation of the corresponding image may include subtracting an amplitude related to the dark current evaluation of the PS from the detection signal of the one or more PSs to give a more accurate characterization of the FOV of the PDA. Optionally, this stage of compensating for the dark current accumulation is performed only for multiple available PSs of the corresponding image.

[0316] In a PDA characterized by relatively high dark current (e.g., as a result of the types and characteristics of its multiple PDs), the capacitance of the individual PSs from which the detection charge is collected may become saturated (partially or completely) due to the dark current, leaving almost no dynamic range for detecting ambient light (reaching from a field of view of the system). Even when a device is implemented to subtract multiple dark current levels from the multiple detection signals (e.g., to normalize the detection data), the lack of dynamic range for detection means that the resulting signal is completely saturated or insufficient to meaningfully detect multiple ambient light levels. Since the dark current from the PD is accumulated in the capacitor of the FET (whether it is the actual capacitor of the multiple PSs or the parasitic or residual capacitance of other components), the method uses the FET to determine which PS can be used in the corresponding FET, leaving sufficient dynamic range in the capacitor after collecting the dark current (or at least a relevant portion thereof) for the entire FET. The identification of an unavailable PS group for a frame may include: identifying, given the FET of the corresponding frame, multiple PSs whose dynamic range is below an acceptable threshold (or otherwise expected to fail a dynamic range adequacy criterion). Similarly, the identification of an available PS group for a frame may include: identifying, given the FET of the corresponding frame, multiple PSs whose dynamic range is above an acceptable threshold (or otherwise expected to meet a dynamic range adequacy criterion). The two acceptable thresholds may be the same or different thresholds (e.g., if the dynamic range of multiple PSs is treated differently between those thresholds, such as being identified as belonging to a group of available PSs of the relevant frame).

[0317] Referring generally to method 2400, it should be noted that for multiple additional FETs (e.g., a fourth FET, and so on), multiple additional instances of multiple stages 2416, 2418, 2420, and 2422 can be repeated. Such times can be longer, shorter, or equal to any previously used FET. It should also be noted that, optionally, the first FET, the second FET, and the third FET are multiple consecutive FETs (i.e., the PDA does not use other FETs between the first FET and the third FET). Alternatively, other FETs can be used between the first FET and the third FET.

[0318] It should be noted that even if the exposure value (EV) remains the same, multiple different groups of available PSs and unavailable PSs can be determined for different FETs in method 2400. For example, consider a case where the first FET is expanded by a factor q to provide the second FET, but the f number is increased by a factor q such that the total illumination received by the PDA is substantially the same. In such a case, even if the EV remains constant, the second group of unavailable PSs will include PSs other than those included in the first group of unavailable PSs because the dark current accumulation increases by a factor p.

[0319] A non-transitory computer-readable medium is provided for generating image information based on data from a PDA. The non-transitory computer-readable medium includes a plurality of instructions stored thereon, which, when executed on a processor, perform the following steps: receiving first frame information, the first frame information including a first frame detection level for each of a plurality of PSs of the PDA, the first frame detection level indicating a light intensity detected by each PS in a first FET; based on the first FET, identifying from the plurality of PSs of the PDA: a first usable PS group including a first PS, a second PS, and a third PS, and a first unusable PS group including a fourth PS; ignoring the plurality of first frame detection levels of the first unusable PS group, generating a first image based on the first frame detection levels of the first usable PS group; after receiving the first frame information, determining a second FET, the FET being longer than the first FET; receiving second frame information, the second frame information including a second frame detection level for each of the plurality of PSs of the PDA, the second frame detection level indicating a light intensity detected by each PS in a second FET. Light intensity; based on a second FET, identifying from the plurality of PSs of the PDD: a second available PS group including the first PS, and a second unavailable PS group including the second PS, the third PS, and the fourth PS; ignoring multiple second frame detection levels of the second unavailable PS group, generating a second image based on the multiple second frame detection levels of the second available PS group; after receiving the second frame information, determining a third FET, the third FET being longer than the first FET and shorter than the second FET; receiving third frame information, the third frame information including a third frame detection level for each of the plurality of PSs of the PDD, the third frame detection level indicating a light intensity detected by each PS in a third FET; based on the third FET, identifying from the plurality of PSs of the PDD: a third available PS group including the first PS and the second PS, and a third unavailable PS group including the third PS and the fourth PS; and ignoring multiple third frame detection levels of the third unavailable PS group, generating a third image based on the multiple third frame detection levels of the third available PS group.

[0320] The non-transitory computer-readable medium mentioned in the previous paragraph may include a plurality of additional instructions stored thereon, which, when executed on a processor, perform any other steps or variations discussed above with respect to method 2400.

[0321] Figure 25This is a flowchart illustrating a method 2500 for generating models for PDA operation in different FETs, based on numerous examples of the currently disclosed subject matter. Identifying which of the plurality of PSs belongs to a group of available PSs provided with a given FET (and numerous possible additional parameters, such as temperature, bias voltage across the plurality of PDs, capacitance of the plurality of PSs, etc.) allows for a model of the behavior of each of the plurality of PSs in different FETs. Such modeling may be part of method 2400 or may be performed separately prior to it. For each of the plurality of PSs in a plurality of PDAs (e.g., PDA 1602), and possibly for all PSs in the photodetector array, multiple stages 2502, 2504, and 2506 of method 2500 are performed.

[0322] Step 2502 includes determining the availability of the corresponding PS for each of the plurality of different FETs. The determination of availability can be performed in different ways. For example, a detection signal of the PS can be compared with a desired value (e.g., if the illumination level is known, it could be complete darkness, or a known high illumination level), with an average value across the other PSs, with multiple detection levels across the other PSs (e.g., if all PSs are imaging a color-uniform target), with multiple detection results across the other FETs (e.g., determining whether the detection level at a duration T, e.g., 200 nanoseconds, is approximately twice the detection level at T / 2, e.g., 330 nanoseconds), and so on. The determined availability can be a binary value (e.g., available or unavailable), a non-binary value (e.g., a scalar assessing the availability level or indicating its availability), a set of values ​​(e.g., a vector), or any other suitable format. Optionally, the same number of frame FETs can be used for all PSs across the plurality of PSs, but this is not mandatory. For example, in a non-binary availability assessment, an intermediate value between completely unavailable and completely available might indicate that, at other available (or partially available) times, the detection signal of the corresponding PS should be combined or averaged with multiple detection signals of multiple adjacent PSs and / or with other readings of the same multiple PSs.

[0323] Method 2500 may include an optional stage 2504 for measuring the charge accumulation capacity and / or saturation parameters of the corresponding PS. The charge capacity may be measured in any suitable manner, such as using a power source from the PD, another power source in the PS (e.g., a current source), another power source in the PDA, or an external power source (e.g., a calibration machine in a manufacturing facility for photodetectors). Stage 2504 may be omitted, for example, when the difference in capacitance between different PSs is negligible or can be simply ignored.

[0324] Phase 2506 includes creating a usability prediction model for the corresponding PS, which provides an estimate of the PS's availability when operating with different FETs not included in the plurality of FETs whose availability was actively determined in Phase 2502. The plurality of different FETs may be included within the same duration span of the plurality of FETs in Phase 2502, longer or shorter. The created usability prediction model can provide different types of availability indications, such as: a binary value (e.g., available or unavailable), a non-binary value (e.g., a scalar assessing availability or its indicative nature), a set of values ​​(e.g., a vector), or any other suitable format. The type of availability indicated by the model may be the same type of availability determined in Phase 2502 or a difference thereof. For example, Phase 2502 may include: assessing the dark current collected in different FETs, while Phase 2504 may include: determining a time threshold indicating the maximum permissible FET for which this PS is considered available. Optionally, the availability model may take into account the charge accumulation capacity of each PS.

[0325] Any suitable method can be used to create the availability prediction model. For example, for different FETs, different dark currents can be measured or evaluated for the PD, and then a regression analysis can be performed to determine a function (polynomial, exponential, etc.) that can be used to evaluate the dark current in multiple other FETs.

[0326] Optional stage 2508 includes: compiling a usability model for at least a portion of the PDA, including at least the plurality of PSs from the previous stages. For example, stage 2508 may include: generating one or more matrices or other types of mappings, which store multiple model parameters for each PS in multiple cells of their respective mappings. For example, if stage 2506 includes creating a dark current linear regression function for each PS(p,s), the dark current linear regression function is defined by DarkCurrent(p,s) = A p,s ·τ+B p,s (where τ is the FET, and A) p,s and B p,s The linear coefficients of the linear regression are provided, and then a matrix A can be generated to store multiple different A's. p,s The values ​​can be used to generate a matrix B to store multiple distinct values. p,s Value. If needed, a third matrix C can be used to store different capacitance values ​​C for multiple different PS. p,s (or different saturation values ​​S) p,s).

[0327] Phase 2506 (or phase 2508, if implemented) may be followed by an optional phase 2510, which includes determining the availability of the plurality of PSs that are not used for one of the plurality of FETs in phase 2502 based on the plurality of results of phase 2506 (or phase 2508, if implemented). For example, phase 2510 may include creating a mask (e.g., a matrix) for the plurality of different PSs of the photodetector array that are unavailable PSs.

[0328] Referring fully to method 2500, stage 2502 may include: determining the dark current of each PS of the PDA at four different FETs (e.g., 33ns, 330ns, 600ns, and 2000ns). Stage 2504 may include: determining a saturation value for each PS, and stage 2506 may include: creating a polynomial regression for the accumulation of dark current over time for each PS. Stage 2508 in this example may include: generating a matrix storing the FET in each cell, wherein the dark current of the PS (according to regression analysis) will saturate the PS. Stage 2510 may include: receiving a new FET and determining whether each cell of the matrix is ​​below or above the stored value by generating a binary matrix storing a first value (e.g., "0") for each unavailable PS (where the FET is above the stored value) and a second value (e.g., "1") for each available PS (where the FET is below the stored value).

[0329] Any stage of method 2500 may be performed during the manufacturing process of the PDA (e.g., during factory calibration), during the operation of the system (e.g., after an EO system including the PDA is installed at its designated location, such as a vehicle, monitoring system, etc.), or at any other suitable time between or after these times. Different stages may be performed at different times.

[0330] The full reference method 2400 should be noted that it can be extended at different stages under different operating conditions (e.g., when subjected to different temperatures, or when multiple different biases are supplied to multiple PDs) to measure the effect of dark current on multiple different PSs in multiple different FETs.

[0331] Optionally, determining a FET (e.g., the second FET, the third FET) as part of method 2400 may include: maximizing the corresponding FET while keeping a number of unavailable PSs for the corresponding frame below a predetermined threshold. For example, to maximize the collection of multiple signals, method 2400 may include: setting a FET close to a threshold, the threshold being related to a predetermined number of unavailable PSs (e.g., requiring at least 99% of the multiple PSs of the PDA to be available, allowing up to 1% of the multiple PSs to be unavailable). It should be noted that in some cases, the maximization may not produce the exact maximum duration, but a duration close to it (e.g., more than 320% or 325% of the mathematically maximum duration). For example, the maximum frame duration may be selected over multiple discrete predefined time spans.

[0332] For example, as part of method 2400, determining a FET may include: determining a FET that is longer than other possible FETs, thereby causing more PSs than a previous FET, such that a higher number of PSs are considered unusable compared to the other possible FETs, but improving image quality in the remaining PSs. This can be useful, for example, in relatively dark conditions. It should be noted that, optionally, the determination of the FET (e.g., by attempting to maximize it) may take into account the spatial distribution of the PSs considered unusable in the multiple different FETs. For example, knowing that in certain areas of the PDA, a cumulative number of PSs has a high percentage of the PSs that will be considered unusable above a certain FET may cause the determination of a FET below the threshold, especially if this is a significant part of the FOV (e.g., at the center of the FOV, or at the location of pedestrians or vehicles identified in a previous frame).

[0333] Method 2400 may include: creating a single image based on multiple detection levels in two or more frames detected at multiple different FETs, wherein multiple different groups of unavailable PSs are used for different FETs. For example, three FETs: ×1, ×10, and ×100 may be used. The color determined for each pixel of the image may be determined based on the multiple detection levels of one or more PSs (e.g., in a FET where the PS is available, unsaturated, and detects a non-negligible signal) or multiple detection levels of multiple adjacent PSs (e.g., if no available detection signal is provided, even if the corresponding PS is determined to be available, such as because the signal is negligible in such a case). Method 2400 may include: determining multiple FETs for combining different exposures of the single image (e.g., using high dynamic range imaging techniques, HDR). The determination of such FETs may be based on modeling the different PS availability in multiple different FETs, such as the model generated in method 2500. Method 2400 may further include: deciding to capture a single image in two or more distinct detection instances (wherein the plurality of detection signals are read separately in each instance and then summed), each detection instance providing sufficient usable PS. For example, instead of using a 2-millisecond FET for a single capture of a scene, method 2400 may include: deciding to capture the scene twice (e.g., two 1-millisecond FETs, one 1.5-millisecond FET, and one 0.5-millisecond FET), such that the number of usable PS in each exposure exceeds a predetermined threshold.

[0334] Optionally, method 2400 may include determining at least one FET based on an availability model of different PSs in different FETs (e.g., generated in method 2500) and saturation data from at least one previous frame captured by the PDA. The saturation data includes information about multiple PSs saturated in at least one FET in at least one previous frame (e.g., the number of PSs, which PSs, and which parts of the PDA) and / or information about multiple PSs nearly saturated in at least one FET in at least one preceding frame. The saturation data may relate to the immediately preceding frame (or several frames), thus indicating the saturation behavior of a curtain-imaged scene.

[0335] Method 2400 may further include: modeling the availability of multiple PSs of the PDA at multiple different FETs (e.g., by implementing method 2500 or any other suitable modeling method). Providing an availability model of multiple PSs of the PDA at multiple different FETs (either part of or not part of method 2400), method 2400 may include: (a) determining at least one of the second FET and the third FET based on the modeling results; and / or (b) identifying at least one of the multiple unavailable PS groups based on the modeling results.

[0336] Optionally, when determining any one or more FETs, method 2400 may include: determining a FET that balances the expansion of the FET due to the darkness of the FOV scene with the reduction of the FET to limit the number of unusable PSs, which increases with a longer FET (e.g., based on the model of method 2500). For example, when at the same temperature and biased on the PD (so that the dark current in each FET remains constant), stage 2408 may include: determining a longer FET because the scene becomes darker (at the expense of a large number of unusable PSs), and stage 2416 may include: determining a shorter FET because the scene brightens again (thus reducing the number of unusable PSs). This is particularly important in darker images, where the availability of multiple PSs limited by the accumulation of dark current (which is caused by temperature and operating conditions rather than illumination levels) will be addressed if the accumulation of dark current does not significantly limit the dynamic range of the individual PSs. In another example, during a time span in which the scene lighting remains constant, stage 2408 may include: deciding on a longer FET that is enabled due to a temperature drop (thereby reducing dark current and reducing the percentage of unusable PS on each FET), while stage 2416 may include: deciding on a shorter FET as the temperature of the PDA rises again.

[0337] Figure 26 This is a graphical representation of the execution of method 2400 for three frames of the same scene captured in different FETs, according to numerous examples of the subject matter of this disclosure. The example scene comprises four concentric rectangles, each darker than its surrounding rectangles. Figure 26 The different graphs correspond to a stage of method 2400 and are numbered with an equivalent reference number marked with an apostrophe. For example: 2406' matches an execution of stage 2406, and so on. Each rectangle in the lower nine graphs represents a single PS, or a pixel directly mapped to such a PS (in the lower three graphs). In all graphs, the positions of the multiple PSs relative to the PDD remain unchanged.

[0338] As is common in many types of PDAs, the PDA receiving frame information from it may include numerous PSs (also referred to as defective, faulty, or otherwise anomalous pixels). The term "misbehaving PS" is broadly related to a PS that deviates from its expected response, including but not limited to: stuck, dead, hot, lit, warm, defective, and flashing PSs. A number of misbehaving PSs may be a single PS or a cluster of multiple PSs. Numerous non-limiting examples of defects that may cause abnormal PS behavior include: PS bump bond connectivity, addressing faults in the multiplexer, vignetting, severe sensitivity deficiency of some PSs, non-linearity, poor signal linearity, low full well, poor mean-variance linearity, excessive noise, and high dark current. One or more PSs identified as unusable in method 2400 may be a permanently faulty PS or a PS that behaves abnormally based on conditions unrelated to the FET (e.g., due to high temperature). Such PSs can be identified as unusable for all FETs in method 2400 (e.g., PS 8012.5). However, it should be noted that due to the limited functionality and sufficiently long FETs (such as PS 8012.4), certain functional PSs (not "misbehaving") may be considered unusable in all FETs of method 2400. Optionally, method 2400 may include determining the availability of one or more PSs of the PDA based on parameters other than the FETs (such as temperature, various electrical parameters, ambient light level). It should be noted that in such a case, a PS that is unusable due to FET reasons due to other considerations (such as temperature) should generally not be considered usable due to its capacitance limitation.

[0339] In the example shown:

[0340] a. It is possible that under all conditions, the PS 8012.5 will have no output signal, regardless of the amount of light impacting it in all three FETs (T1, T2, T3).

[0341] b. It is possible that the PS 8012.4 outputs a saturated signal under all conditions, regardless of the amount of light impacting it in all three FETs (T1, T2, T3).

[0342] c. The PS 8012.3 outputs a usable signal on the shortest FET (T1), but an unusable (saturated) signal on the longer FETs (T2 and T3).

[0343] d.PS 8012.2 outputs a usable signal on several shorter FETs (T1 and T3), but outputs an unusable (saturated) signal on the longest FET (T2).

[0344] It should be noted that other types of defects and erroneous outputs may also occur. For example, such errors may include: outputting a highly non-linear signal response, consistently outputting a signal that is too strong, consistently outputting a signal that is too weak, outputting random or semi-random output, and so on. Similarly, many PSs (such as the first PS 8012.1) can be used to detect all FETs used in the process.

[0345] Back Figure 23 It should be noted that, optionally, system 2300 may be an EO system with dynamic PS availability assessment capability. That is, EO system 2300 may be able to alternately assign multiple different PSs as available or unavailable based on FET and possibly other operating parameters, and utilize multiple detection signals of multiple PSs (e.g., according to an availability model) only when each PS is determined to be available at capture time.

[0346] In this case, the EO system 2300 includes:

[0347] a. PDA 2302, which includes a plurality of PS2306, each PS2306 being operable to output a plurality of detection signals in different frames. The detection signal output by the respective PS2306 for a frame indicates the amount of light impacting the respective PS in that frame (and may also indicate the dark current of the PD at the respective PS).

[0348] b. An availability filtering module (e.g., implemented as part of processor 2304, or as a separate implementation thereof). The availability filtering module is operable to determine that a PS 2306 is unavailable based on a first FET for each PS 2306 (which may differ between different PS 2306), and later determine that the same PS 2306 is available based on a second FET that is shorter than the first FET. That is, many PS 2306s that are unavailable at a certain point (and whose outputs are ignored when generating one or more images) may later become available again (e.g., if the FET becomes shorter), and the many outputs of these PS 2306s may be used to generate many subsequent images.

[0349] c. Processor 2304 is operable to generate multiple images based on multiple frame detection levels of the plurality of PSs 2306. In other configurations of processor 2304, it is configured to: (a) when generating a first image based on a plurality of first frame detection levels, exclude a first detection signal of a filtered PS, the first detection signal of the filtered PS being determined by the availability filtering module to be unusable for the first image; and (b) when generating a second image based on a plurality of second frame detection levels captured by the PDA after capturing the plurality of first frame detection levels, include a second detection signal of the filtered PS being determined by the availability filtering module to be usable for the second image.

[0350] Optionally, the controller 2314 may determine different FETs for different frames based on the different illumination levels of multiple objects in the field of view of the EO system.

[0351] Alternatively, controller 2314 may be configured to determine the number of FETs for the EO system by maximizing multiple FETs while keeping the number of unavailable PSs for each frame below a predetermined threshold (e.g., as discussed with respect to method 2400).

[0352] Optionally, the EO system 2300 may include: at least one shielding PD, which is shielded (e.g., by a physical barrier or using deflecting optics) from ambient illumination; and dedicated circuitry operable to output electrical parameters indicating the level of dark current based on the signal level of the at least one shielding PD. The processor 2304 may be configured to generate multiple images based on the electrical parameters, on corresponding FETs, and on the plurality of detection signals from the PDA, thereby compensating for different degrees of dark current accumulation in different frames.

[0353] Optionally, the processor 2304 may be configured to calculate a replacement value for at least one pixel of the first image associated with the filtered PS based on a detection level of the filtered PS measured when the PS is identified as available. Optionally, the processor 2304 may be configured to calculate multiple replacement values ​​for multiple PSs, based on the detection levels of multiple neighboring PSs, when the detection signals of each PS are excluded from the generation of multiple images. Optionally, the processor 2304 may be operated based on a first frame detection level of multiple neighboring PSs to calculate a replacement value for at least one pixel of the first image associated with the filtered PS.

[0354] Optionally, the processor 2304 (or availability filter module, if not part of the processor) may be operated to determine an availability level for a plurality of PSs based on a FET, the level comprising a sum of the durations during which the PDD samples the plurality of PSs to be light-sensitive, and excluding a plurality of intermediate times between the plurality of durations during which the plurality of PSs are not light-sensitive.

[0355] Optionally, processor 2304 may utilize an availability model generated according to method 2500 to determine when to include and when to exclude multiple detection signals from different PSs captured by different FETs. Optionally, EO system 2300 may operate to perform method 2500. Optionally, EO system 2300 may be configured to participate in the execution of method 2500 together with an external system (such as a factory calibration machine used in the manufacture of EO system 2300).

[0356] Figure 27This is a flowchart illustrating an example of method 3500 according to the currently disclosed subject matter. Method 3500 is used to generate multiple images based on different subsets of multiple photodetectors (PSs) under different operating conditions. Referring to the numerous examples illustrated with reference to the preceding figures, method 3500 can be executed by processor 1604, wherein the PDA of method 3500 can optionally be PDA 1602. Method 3500 includes at least a plurality of stages 3510, 3520, 3530, and 3540, which are repeated sequentially for different frames captured by a photodetector array. The sequence can be performed completely for each frame in a stream, but it is not necessary, as discussed in more detail below.

[0357] The sequence begins at stage 3510, where frame information is received from the PDA, indicating multiple detection signals provided by multiple PSs of the PDA for the frame. The frame information may include: a detection level (or multiple levels) for each PS (e.g., between 0 and 1024, three RGB values, each between 0 and 255, etc.), or any other format. The frame information may indicate multiple detection signals indirectly (e.g., relative to the level of an adjacent PS or relative to the level of the same PS in a previous frame to give information relating to the detection level of a given PS). The frame information may also include: additional information (e.g., sequence number, timestamp, operating conditions), some of which may be used in subsequent steps of method 3500. The frame information received from the PDA may include: faulty, defective, or otherwise abnormally behaving PSs.

[0358] Phase 3520 includes receiving operational status data during the frame duration, the operational status data indicating multiple operational conditions of the PDA. These multiple operational conditions can be received from different types of entities, such as any one or more of the following entities: the PDA, a controller of the PDA, the at least one processor executing method 3500, one or more sensors, one or more controllers of the at least one processor executing method 3500, and so on. Multiple non-limiting examples of the multiple operational conditions that may be mentioned in phase 3520 include the PDA's FET (e.g., electronic or mechanical shutter, flash illumination duration, etc.), the amplification gain of the PDA or connected circuitry, the bias voltage supplied to the multiple PDs of the PDA, ambient light level, dedicated illumination level, image processing mode of a downstream image processor, filtering applied to the light (e.g., spectral filtering, polarization), and so on.

[0359] Phase 3530 includes determining a defective PS group based on the operational condition data, which includes at least one of the plurality of PSs and excludes a plurality of other PSs. When phase 3530 is executed for different frames based on different operational condition data received for these frames in different corresponding instances of phase 3520, different defective PS groups are selected for different frames with different operational conditions. However, the same group of defective pixels can be selected for two frames with different operational conditions (e.g., when the difference in operational conditions is relatively small).

[0360] It should be noted that the decision is based on the operating condition data, not on an evaluation of the plurality of PSs themselves. Therefore, the defectiveness of the various PSs included in different groups is an estimate of their conditions, not a statement of their actual operability conditions. Thus, a PS included in the defective PS group in stage 3530 is not necessarily defective or inoperable under the plurality of operating conditions indicated in the operating condition data. The decision in stage 3530 aims to match the actual state of the PDA as accurately as possible.

[0361] Step 3540 includes processing the frame information to provide an image representing the frame. The processing is based on multiple detection signals from multiple PSs of the photodetector, but excludes multiple PSs in the defective PS group. That is, the multiple detection signals from the multiple PSs of the PDA are used to generate an image representing the field of view (or other scene, or one or more objects to which light reaches the PDA), but all detection signals originating from the multiple PSs are excluded from the defective PS group (as previously stated, this is dynamically determined based on operating condition data in the captured relevant frame information). Step 3540 may optionally include calculating multiple replacement values ​​to compensate for multiple ignored detection signals. Such calculations may include, for example, determining a replacement value for a defective PS based on multiple detection signals from multiple neighboring PSs. Such calculations may include, for example, determining a replacement value for a pixel of the image based on multiple values ​​from multiple neighboring pixels of the image. Any techniques discussed above regarding image generation in method 2400 may also be used for image generation in step 3540.

[0362] An example of performing the method on two frames (a first frame and a second frame) may include: for example:

[0363] a. Receive from the PDA first frame information indicating a plurality of first detection signals provided by a plurality of PSs and relating to a first frame duration, wherein the plurality of PSs includes at least a first PS, a second PS, and a third PS. A frame duration is the time from light to a single image or a frame of video summarized by the PDA. Different frame durations may be mutually exclusive, but in some embodiments they may optionally be partially overlapped.

[0364] b. Receive first operating condition data, the first operating condition data indicating the operating conditions of the PDA during the duration of the first frame.

[0365] c. Determine a first defective PS group based at least on the first operating condition data, including the third PS, but excluding the first PS and the second PS. The determination may include: directly determining the first defective PS group, or determining other data that suggests which pixels are considered defective (e.g., determining a complement of defect-free pixels, assigning a defect level to each pixel, and then setting a threshold or other determination criteria).

[0366] d. Process the first frame information based on the first defective PS group to provide a first image, such that the processing is based at least on the plurality of first detection signals of the first PS and the second PS (optionally, after previous preprocessing, such as digitization, setting an upper limit, level adjustment, etc.), and ignores information related to the plurality of detection signals of the third PS.

[0367] e. Receive second frame information from the PDA, the second frame information indicating multiple second detection signals provided by multiple detection PSs. The second frame information relates to a second frame duration other than the duration of the first frame.

[0368] f. Receive second operating condition data, which indicates multiple operating conditions of the PDA during the duration of the second frame, and which differs from the first operating condition data. It should be noted that the second operating condition data can be received from the same source as the first operating condition data, but this is not mandatory.

[0369] g. Based on the plurality of second operating conditions, determine data for a second defective PS group, including the second PS and the third PS, but excluding the first PS. The determination may include: directly determining the second defective PS group, or determining other data that suggests which pixels are considered defective (e.g., determining a complement of defect-free pixels, assigning a defect level to each pixel, and then setting a threshold or other determination criteria).

[0370] h. The second frame information is processed based on the second defective PS group to provide a second image, such that the processing of the second image information is based at least on the plurality of second detection signals of the first PS, and information relating to the plurality of detection signals of the second PS and the third PS is ignored.

[0371] Figure 28A The diagram illustrates a system 3600 and several exemplary target objects 3902 and 3904, representing numerous examples of the currently disclosed subject matter. The EO system 3600 includes at least a processor 3620 operable to process multiple detection signals from at least one PDA (potentially part of the same system, but not necessarily) to generate multiple images representing multiple objects within a field of view of the system 3600. The system 3600 may be implemented by a system 2300 and uses similar reference numerals (e.g., in such a case, PDA 3610 may be PDA 2302, controller 3640 may be controller 2314, and so on), but this is not mandatory. For the sake of brevity, not all the descriptions provided above regarding system 2300 are repeated, and it should be noted that any combination of one or more components of system 2300 may be implemented in system 3600 by analogy, and vice versa. System 3600 may be a processing system (e.g., a computer, a graphics processing unit) or an EO system, further including a PDA 3610 and optics. In the latter case, system 3600 may be any type of EO system using a PDA for detection, such as a camera, a spectrometer, a LiDAR, and the like. Optionally, system 3600 may include one or more illumination sources 3650 (e.g., multiple lasers, multiple LEDs) for illuminating multiple objects in the FOV (e.g., illuminating the objects for at least the first FET and the second FET). Optionally, system 3600 may include a controller 3640 that can determine different FETs for different frames based on different illumination levels of the multiple objects in the EO system's field of view. Optionally, those different FETs may include the first FET and / or the second FET.

[0372] exist Figure 28A Two exemplary targets are shown: a dark-colored car 3902 with a highly reflective panel (a body panel with low reflectivity), and a black rectangular panel 3904 with a white patch on it. It should be noted that the system 3600 is not limited to generating multiple images of multiple low-reflectivity objects with multiple high-reflectivity patches. However, the way the system 3600 generates multiple images of such targets is interesting.

[0373] Processor 3620 is configured to receive multiple detection results of an object from a PDA (e.g., PDA 3610, if implemented), the object comprising a high-reflectivity surface surrounded on all sides by multiple low-reflectivity surfaces (e.g., multiple targets 3902 and 3904). The multiple detection results include: (a) a first frame of information of the object detected by the PDA in a first FET, and (b) a second frame of information of the object detected by the PDA in a second FET longer than the first FET. The first and second frame information indicate multiple detection signals output by different PSs of the PDA, which in turn indicate multiple light intensities of different portions of the target detected by the PDA. Some PSs detect light from the low-reflectivity portions of the multiple objects, while at least another PS detects light from the high-reflectivity surface.

[0374] Based on different FETs, the processor 3620 processes the first frame information and the second frame information in different ways. Figure 28B Exemplary first and second images of multiple targets 3902 and 3904, according to numerous examples of the currently disclosed subject matter, are illustrated. When processing the first frame information, processor 3620 processes the first frame information based on the first FET. It generates a first image comprising a bright area representing the high-reflectivity surface, surrounded by a dark background representing the low-reflectivity surface. This is in Figure 28B The diagram is illustrated as multiple first images 3912 and 3914 (corresponding to) Figure 28A Multiple objects 3902 and 3904). When processor 3620 processes second frame information that is longer than the first FET based on the second FET, Tt generates a second image, the second image including a dark background without any bright areas. This is in Figure 28B The illustration is provided as multiple second images 3922 and 3924 (corresponding to) Figure 28A Multiple objects 3902 and 3904).

[0375] That is, even if more light from highly reflective surfaces reaches the individual PSs of the photodetector in the second frame, the image output will not be brighter or more saturated, but rather darker. Processor 3620 can determine the darker color (which has multiple lower-intensity signals because they capture the lower reflective surfaces of the object) of the plurality of pixels representing the highly reflective surfaces in the second image by using information from neighboring PSs, since it determines that the multiple signals from the multiple associated PSs are unavailable in that longer second FET. Optionally, processor 3620 can be configured to discard the multiple detected light signals corresponding to the highly reflective surfaces when generating the second image based on the second FET (and optionally also based on availability modeling of the individual PSs, such as as discussed with respect to method 2500), and to be configured to calculate a dark color for at least one corresponding pixel in the second image in response to the multiple light intensities detected from the multiple adjacent low-reflective surfaces of the object captured from the multiple neighboring PSs. Optionally, the processor 3620's decision to discard the information of the corresponding PS is not based on the detection signal level, but on the sensitivity of the corresponding PS to dark current (e.g., finite capacitance). Optionally, when processing the second frame information, the processor 3620 may, based on the second FET, for example, similar to the plurality of recognition stages of method 2400, identify at least one PS that detects light from the high reflectivity surface as unusable for the second frame.

[0376] It should be noted that the high-reflectivity surface may be smaller than the low-reflectivity surface and may be surrounded by the low-reflectivity surface on all sides, but this is not mandatory. The size (e.g., angular size) of the high-reflectivity surface may correspond to a single PS, less than one PS, or several PS. The difference between the high-reflectivity level and the low-reflectivity level can vary. For example, the reflectivity of the low-reflectivity surface may be between 0% and 15%, while the reflectivity of the high-reflectivity surface may be between 80% and 100%. In another example, the low-reflectivity surface may have a reflectivity between 50% and 55%, while the high-reflectivity surface may have a reflectivity between 65% and 70%. For example, the minimum reflectivity of the high-reflectivity surface may be ×2, ×3, ×5, ×10, or ×100 of the maximum reflectivity of the low-reflectivity surface. Optionally, the high-reflectivity surface has a reflectivity greater than 95% (e.g., a white surface) within the spectral range detectable by the plurality of PSs, while the low-reflectivity surface has a reflectivity less than 5% (e.g., a black surface) within the spectral range detectable by the plurality of PSs. It should be noted that, as described above, a FET can correspond to a fragmented time span (e.g., several illumination pulses) or a single continuous time span.

[0377] It should be noted that, optionally, the amounts of multiple optical signal levels reaching the associated PS from the highly reflective surface in the first FET and in the second FET can be similar. This can be achieved by filtering the incoming light and correspondingly changing the f-number of the detection optics 3670 (e.g., increasing the FET by a factor q, and increasing the f-number by a factor q). Optionally, a first exposure value (EV) of the PDA in capturing the first frame information differs from a second EV of the PDA in capturing the second frame information by less than 1%. Optionally, the difference in the FETs is the only major difference between the operating conditions between the first and second frames.

[0378] As discussed above, the temperature of the PDA is evaluated to calibrate the availability model to different levels of dark current. Optionally, the processor 3620 may be further configured to: (a) process the detection signal reflected from the object to determine a first temperature assessment of the photodetector array in capturing the first frame information, and to determine a second temperature assessment of the photodetector array in capturing the first frame information, and (b) based on the second FET and the second temperature assessment, decide to discard a plurality of detection results corresponding to the high reflectivity surface.

[0379] Figure 29 This is a flowchart illustrating a method 3700 for generating image information based on data from a PDA, according to numerous examples of the subject matter of this disclosure. Referring to the examples illustrated with respect to the preceding figures, it should be noted that method 3700 may optionally be performed by system 3600. Any variations discussed above regarding system 3600 may be applied analogously to method 3700. In particular, method 3700 (and its at least several stages 3710, 3720, 3730, and 3740) may be performed by processor 3620.

[0380] Phase 3710 includes receiving a first frame of information from the PDA of a black target comprising a white area, the first frame of information indicating the light intensity of different portions of the target detected by the PDA in a first FET. It should be noted that the white area can be replaced by a bright area (or other highly reflective area). For example, any area with a reflectivity greater than 50% can be used instead. It should also be noted that the black target can be replaced by a dark area (or other slightly reflective area). For example, any target with a reflectivity less than 10% can be used instead.

[0381] Stage 3720 includes processing the first frame information based on the first FET to provide a first image, the first image including a bright area surrounded by a dark background. Optionally, stage 3720 can be implemented using any of the image generation processes discussed above with respect to stages 2406, 2414, and 2422 of method 2400.

[0382] Phase 3730 includes receiving a second frame of information from the PDA, which includes a white area of ​​a black target. The second frame of information is an indication of multiple light intensities of different portions of the target detected by the PDA in a second FET that is longer than the first FET.

[0383] Step 3740 includes processing the second frame information based on the second FET to provide a second image, the second image including a dark background without a bright area. Optionally, step 3740 can be implemented using any of the image generation processes discussed above with respect to any of steps 2406, 2414, and 2422 of method 2400, as well as the previous stage of identifying multiple available and unavailable PS groups.

[0384] Regarding the execution order of method 3700, stage 3720 is executed after stage 3710, and stage 3740 is executed after stage 3730. Alternatively, any suitable stage order can be used. Method 3700 may also optionally include capturing the first frame information and / or the second frame information via a PDA.

[0385] Optionally, after receiving the first frame information, the second FET can be determined before receiving the second frame information, and the second FET is longer than the first FET. Optionally, the processing of the second frame information may include: discarding the light intensity information of the detected white area based on the second FET; determining a dark color for at least one corresponding pixel of the second image in response to multiple light intensities of multiple adjacent areas detected by the second frame information. Optionally, the processing of the second frame information may include: identifying at least one PS based on the second FET, the at least one PS detecting that light from the white area is unusable in the second frame. Optionally, a first exposure value (EV) of the PDA in capturing the first frame information may differ from a second EV of the PDA in capturing the second frame information by less than 1%.

[0386] Optionally, during the first frame exposure time, the dark current accumulation on the PS associated with the low reflectivity data leaves a usable dynamic range for the PS, while during the second frame exposure time, the dark current accumulation on that PS leaves an insufficient dynamic range for the PS. In such a case, the PS corresponding to the high reflectivity region cannot be used for image generation in the second image, and a replacement color value can be calculated to replace the lost detection level.

[0387] A non-transitory computer-readable medium is provided for generating image information based on data (including a plurality of instructions stored thereon) of a PDA, the image information, when executed on a processor, performing the following steps: (a) receiving from the PDA a first frame of information about a black target, the black target including a white region, the first frame of information indicating the light intensity of different portions of the target detected by the PDA in a first FET; (b) processing the first frame of information based on the first FET to provide a first image, the first image including a bright region surrounded by a dark background; (c) receiving from the PDA a second frame of information about the black target, the black target including the white region, the second frame of information indicating the light intensity of different portions of the target detected by the PDA in a second FET longer than the first FET; and (d) processing the second frame of information based on the second FET to provide a second image, the second image including a dark background without a bright region.

[0388] The aforementioned non-transitory computer-readable medium may include other instructions stored thereon, which, when executed on a processor, perform any other steps or variations discussed above with respect to method 3700.

[0389] The foregoing disclosure describes various systems, methods, and computer code products, as well as ways of utilizing them to capture and generate high-quality images photoelectrically. In particular, in the presence of high PD dark current, such systems, methods, and computer code products can be used to generate multiple high-quality SWIR images (or other SWIR sensing data). These multiple PDs can be multiple germanium PDs, but not in all cases. Some ways of using such systems, methods, and computer program products in a synergistic manner are discussed above, and many other ways are possible and considered part of the inventive subject matter of this disclosure. Any system discussed above can be combined with any one or more components of any one or more other systems discussed above to achieve higher quality results, achieve similar results in a more efficient or cost-effective manner, or for any other reason. Similarly, any method discussed above can be combined with any one or more stages of any one or more other methods discussed above to achieve higher quality results, achieve similar results in a more efficient or cost-effective manner, or for any other reason.

[0390] The following paragraphs provide some non-restrictive examples of such combinations to demonstrate certain possible synergies.

[0391] For example, imaging systems 100, 100', and 100" with sufficiently short integration times to overcome the excessive influence of dark current noise can implement multiple PDDs, such as multiple PDDs 1300, 1300', 1600, 1600', 1700, and 1800, which are included in receiver 110 to reduce the time-invariant (DC) portion of the dark noise. In this way, the capacitance of the multiple PSs will not be overwhelmed by the time-invariant portion of the dark current not accumulated in the detection signal, and the noise of the dark current will not cloud the detection signal. Implementing any one of the multiple PDDs 1300, 1300', 1600, 1600', 1700, and 1800 in any of the multiple imaging systems 100, 100', and 100" can be used to extend the frame exposure time to a significant extent (because the DC portion of the dark current will not accumulate in the capacitance) while still detecting a meaningful signal.

[0392] For example, imaging systems 100, 100', and 100" whose integration time is set short enough to overcome the excessive influence of dark current noise can implement any one or more of methods 2400, 2500, and 3500 to determine the number of PSs available at that frame exposure time, and may reduce the frame exposure time (which corresponds to the integration time) to further determine a sufficient number of PSs available. Similarly, the expected ratio between the readout noise of a given FET and the expected accumulated dark current noise level, and the expected availability of different PSs in such a PS, can be used by the controller to set a balance between the quality of the detected signal, the number of available pixels, and the required illumination level of the light source (e.g., laser 600). When applicable, the availability model of different FETs can also be used to determine the distance ranging from the multiple gated images generated by imaging systems 100, 100', and 100" Incorporating any of the multiple PDD 1300, 1300', 1600, 1600', 1700, 1800 into the sensor of such an imaging system would increase the benefits discussed in the preceding paragraph.

[0393] For example, any one or more of methods 2400, 2500, and 3500 can be implemented by system 1900 (or by any EO system including any one of multiple PDDs 1300, 1300', 1600, 1600', 1700, and 1800). The reduction of the various effects of dark current accumulation discussed with respect to system 1900 (or any of the mentioned PDDs) allows for the use of multiple longer FETs. Implementing any of these methods can facilitate longer FETs because determining which PSs are temporarily unavailable in a relatively long FET allows system 1900 (or another EO system having one of the mentioned multiple PDDs) to ignore these PSs and optionally replace their detection outputs with data from multiple adjacent PSs.

[0394] Certain stages of the aforementioned method can also be implemented in a computer program running on a computer system, the computer program including at least a plurality of code portions for performing the various steps of the relevant method when running on or activating a programmable device such as a computer system, to perform various functions of an apparatus or system according to the present disclosure. Such a method can also be implemented in a computer program running on a computer system, the computer program including at least a plurality of code portions causing a computer to perform the various steps of a method according to the present disclosure.

[0395] A computer program is a list of instructions, such as a specific application program and / or an operating system. A computer program may include, for example, one or more of the following: a subroutine, a function, a procedure, a method, an implementation scheme, an executable application, an applet, a service applet, source code, code, a shared library / dynamically loaded library, and / or other sequences of instructions designed to execute on a computer system.

[0396] The computer program may be internally stored on a non-transitory computer-readable medium. All or some of the computer programs may be provided on a computer-readable medium that is permanently, removably, or remotely coupled to an information processing system. The computer-readable medium may include, but is not limited to, any number of the following: magnetic storage media, including magnetic disk and magnetic tape storage media; optical storage media, such as optical disc media (e.g., CD-ROM, CD-R, etc.) and digital video disk storage media; non-volatile storage media, including semiconductor-based memory cells, such as flash memory, EEPROM, EPROM, ROM; ferromagnetic digital memory; MRAM; and volatile storage media, including numerous registers, buffers, or caches, main memory, RAM, etc.

[0397] A computer process typically includes an executable (running) program or a part of a program, various current program values ​​and state information, and the operating system used to manage the execution of the process. An operating system (OS) is software that manages the many shared resources of a computer and provides an interface for programmers to access these resources. An operating system processes system data and user input, and responds to the system's many users and programs by allocating and managing tasks and internal system resources.

[0398] The computer system may include, for example, at least one processing unit, associated memory, and multiple input / output (I / O) devices. When the computer program is executed, the computer system processes information according to the computer program and generates result output information via the various I / O devices.

[0399] The numerous connections discussed herein can be any type of connection suitable for transmitting signals from or to various nodes, units, or devices, for example, via numerous intermediate means. Therefore, unless otherwise implied or stated, the numerous connections can be, for example, direct or indirect connections. The numerous connections can be illustrated or described with reference to a single connection, multiple connections, unidirectional connections, or bidirectional connections. However, different embodiments can vary the implementation of the numerous connections. For example, a single unidirectional connection can be used instead of a bidirectional connection, and vice versa. Furthermore, a single connection can replace multiple connections, which transmit multiple signals serially or in a time-multiplexed manner. Similarly, numerous single connections carrying multiple signals can be separated into various different connections carrying subsets of these signals. Therefore, many options exist for transmitting signals.

[0400] Optionally, the numerous examples illustrated herein can be implemented as circuits located on a single integrated circuit or within the same device. Alternatively, the numerous examples can be implemented as any number of discrete integrated circuits or discrete devices interconnected with each other in a suitable manner. Optionally, suitable portions of the numerous methods can be implemented as a soft or coded representation of physical circuitry or a logical representation that can be converted to physical circuitry, such as in any suitable type of hardware description language.

[0401] Other modifications, variations, and substitutions are also possible. Therefore, the specification and drawings should be considered illustrative rather than restrictive. Although certain features of this disclosure have been illustrated and described herein, many modifications, substitutions, alterations, and equivalents will now appear to those skilled in the art. Therefore, it is to be understood that the appended claims are intended to cover all such modifications and alterations falling within the true spirit of this disclosure. It will be understood that the above embodiments are cited by way of example only, and various features thereof, as well as combinations of such features, can be changed and modified. Although various embodiments have been shown and described, it should be understood that such disclosure is not intended to limit this disclosure, but rather to cover all modifications and alternative constructions falling within the scope of this disclosure, as defined in the appended claims.

[0402] In the claims or description of this application, unless otherwise stated, adjectives such as “substantially” and “about” modifying a conditional or relational characteristic of one or more features of an embodiment are understood to mean that the condition or characteristic is defined within an acceptable tolerance range for the operation of the embodiment for a intended application. It should be understood that where the element “a” or “an” is referenced in the claims or description, such reference should not be construed as including only one of the elements.

[0403] All patent applications, white papers, and other publicly available data published by the assignee of this disclosure and / or TriEye LTD., Tel Aviv, Israel, are incorporated herein by reference in their entirety. No references cited herein are acknowledged as prior art.

Claims

1. An active shortwave infrared imaging system, characterized in that: include: A pulsed illumination source operable to emit multiple pulses of short-wave infrared radiation toward a target, the multiple pulses of radiation impacting the target and causing multiple pulses of short-wave infrared radiation reflected from the target; An imaging receiver includes a plurality of germanium photodiodes operable to detect the reflected shortwave infrared radiation, wherein the imaging receiver generates for each of the plurality of germanium photodiodes a plurality of corresponding detection signals representing the reflected shortwave infrared radiation impacting each of the plurality of germanium photodiodes, a dark current greater than 50 μA / cm², a time-dependent dark current noise, and a time-independent readout noise; and A controller operable to control the activation of the imaging receiver during an integration time, during which a cumulative dark current noise does not exceed the readout noise of the irrelevant time.

2. The active shortwave infrared imaging system according to claim 1, characterized in that: The active shortwave infrared imaging system further includes a readout circuit for reading out a charge accumulation collected by each of the plurality of germanium photodiodes after the integration time to provide the corresponding detection signal.

3. The active shortwave infrared imaging system according to claim 1, characterized in that: The imaging receiver outputs a corresponding set of detection signals, which represents the charge accumulated by each of the plurality of germanium photodiodes during the integration time, wherein the corresponding set of detection signals represents the image of the target illuminated by at least one pulse of shortwave infrared radiation.

4. The active shortwave infrared imaging system according to claim 1, characterized in that: The active shortwave infrared imaging system includes at least one diffractive optical element operable to improve the illumination uniformity of the pulsed illumination source before emitting the radiation.

5. The active shortwave infrared imaging system according to claim 1, characterized in that: The controller is operable to activate the imaging receiver to sequentially acquire a series of gated images, each gated image representing the plurality of corresponding detection signals of each of the plurality of germanium photodiodes within a different distance range, and wherein the active shortwave infrared imaging system further includes an image processor operable to combine the series of gated images into a single two-dimensional image.

6. The active shortwave infrared imaging system according to claim 1, characterized in that: The active shortwave infrared imaging system is an uncooled germanium-based shortwave infrared imaging system, operable to detect a 1-meter by 1-meter target at a distance of more than 50 meters with a shortwave infrared reflectivity of 20%.

7. The active shortwave infrared imaging system according to claim 2, characterized in that: The imaging receiver outputs a corresponding set of detection signals, which represents the charge accumulated by each of the plurality of germanium photodiodes during the integration time, wherein the corresponding set of detection signals represents an image of the target illuminated by at least one pulse of shortwave infrared radiation, wherein the controller is operable to activate the imaging receiver to sequentially acquire a series of gated images, each gated image representing the plurality of corresponding detection signals of each of the plurality of germanium photodiodes within a different distance range, and wherein the active shortwave infrared imaging system further includes an image processor operable to combine the series of gated images into a single two-dimensional image.

8. The active shortwave infrared imaging system according to claim 7, characterized in that: The active shortwave infrared imaging system is an uncooled germanium-based shortwave infrared imaging system, operable to detect a 1-meter by 1-meter target at a distance of more than 50 meters with a shortwave infrared reflectivity of 20%.

9. The active shortwave infrared imaging system according to claim 2, characterized in that: The controller is operable to activate the imaging receiver to sequentially acquire a series of gated images, each gated image representing the plurality of corresponding detection signals of each of the plurality of germanium photodiodes within a different distance range, and wherein the active shortwave infrared imaging system further includes an image processor operable to combine the series of gated images into a single two-dimensional image.

10. The active shortwave infrared imaging system according to claim 9, characterized in that: The active shortwave infrared imaging system is an uncooled germanium-based shortwave infrared imaging system, operable to detect a 1-meter by 1-meter target at a distance of more than 50 meters with a shortwave infrared reflectivity of 20%.

11. A method for generating multiple shortwave infrared images of multiple objects in a field of view of an electro-optic system, characterized in that: The method includes: At least one illumination pulse is emitted toward the field of view, causing short-wave infrared radiation reflected from at least one target; A continuous signal acquisition is triggered by an imaging receiver, which includes a plurality of germanium photodiodes operable to detect the reflected shortwave infrared radiation. The charge collected by each germanium photodiode as a result of the triggering is caused by at least the following: the impact of the short-wave infrared reflected radiation on each germanium photodiode, a dark current greater than 50 μA / cm², a dark current noise related to the integration time, and a readout noise unrelated to the integration time. When the amount of charge collected due to the dark current noise is lower than the amount of charge collected due to the readout noise of the irrelevant integration time, the collection of the charge is stopped; and An image of the field of view is generated based on multiple levels of charge collected by each germanium photodiode.

12. The method according to claim 11, characterized in that: The subsequent step of the collection process involves reading a readout signal related to the amount of charge collected by each germanium photodiode via a readout circuit. Amplify the read signal to generate an amplified signal, and The amplified signal is provided to an image processor that performs the generation of the image.

13. The method according to claim 11, characterized in that: The signal output by each germanium photodiode is a scalar value representing the amount of light reflected from 20 meters, 40 meters, or 60 meters.

14. The method according to claim 13, characterized in that: The generation includes generating the image based on the scalar value read for each germanium photodiode.

15. The method according to claim 11, characterized in that: The method further includes: Repeat the sequence of launch, trigger, collection, and stop multiple times; The acquisition of the continuous signals at different times is triggered from the transmission in each sequence; and in each sequence, The imaging receiver reads a detection value for each germanium photodiode corresponding to a different distance range greater than 2 meters to provide multiple detection values, wherein generating an image includes generating a single two-dimensional image based on the multiple detection values ​​read in each sequence.

16. The method according to claim 11, characterized in that: The method includes performing the collection when the imaging receiver is operating at a temperature above 30 degrees Celsius, and the method further includes processing the image of the field of view to detect multiple vehicles and multiple pedestrians within a range of 50 meters to 150 meters.

17. The method according to claim 16, characterized in that: The method further includes: Repeat the sequence of launch, trigger, collection, and stop multiple times; The acquisition of the continuous signals at different times is triggered from the transmission in each sequence; and in each sequence, The imaging receiver reads a detection value for each germanium photodiode corresponding to a different distance range greater than 2 meters to provide multiple detection values, wherein generating an image includes generating a single two-dimensional image based on the multiple detection values ​​read in each sequence.

18. The method according to claim 17, characterized in that: The signal output by each germanium photodiode is a scalar value representing the amount of light reflected from 20 meters, 40 meters, or 60 meters, wherein the generation includes generating the image based on the scalar value read for each germanium photodiode.

Images