Custom pixel dynamic adjustment system and method for germanium-silicon photodetector arrays

Abstract

This invention belongs to the field of photoelectric detection technology, and particularly relates to a custom pixel dynamic adjustment system and method for a germanium-silicon photodetector array. The system comprises: a germanium-silicon photodetector array sampling the same target scene multiple times with an initial sampling count; the germanium-silicon photodetector array receiving the target light signal and converting it into a current signal; a transimpedance amplifier converting the corresponding current signal into a voltage signal and linearly amplifying the voltage signal; a high-speed analog-to-digital converter converting the amplified voltage signal into a digital signal; a sampling and data fusion module superimposing the corresponding digital signals output by each high-speed analog-to-digital converter pixel-by-pixel to generate a real-time image; and a dynamic optimization module adjusting the sampling count pixel-by-pixel based on the grayscale matrix of the real-time image to obtain the target image. This invention adjusts the exposure time of the next frame in real time using the data from the previous frame to obtain a clear and distortion-free image.

Description

Technical Field

[0001] This invention belongs to the field of photoelectric detection technology, and particularly relates to a custom pixel dynamic adjustment system and method for germanium-silicon photodetector arrays. Background Technology

[0002] A photodetector is a device that converts light signals into electrical signals, and it is widely used in optical communication, optical measurement, and photoelectric imaging. The working principle of a photodetector is based on the photoelectric effect, which can be divided into the external photoelectric effect and the internal photoelectric effect. Internal photoelectric effect: The phenomenon where electrons within an object are emitted outwards from the object's surface under the influence of light. When a metal surface is irradiated with specific light, and the wavelength of the light is less than a certain critical value, the metal absorbs photons and emits photoelectrons. External photoelectric effect: The phenomenon where light shining on an object causes a change in the object's conductivity or generates a photo-generated electromotive force. In semiconductor materials, when the incident light energy hν ≥ Eg (Eg is the band gap), electrons in the valence band absorb photon energy and jump to the conduction band, forming electron-hole pairs, thereby changing the material's conductivity.

[0003] Traditional photodetectors exhibit significant drawbacks due to their inherent physical mechanisms and performance limitations when dealing with overexposure (incident light power far exceeding the upper limit of the detection range) and underexposure (incident light power below the lower limit of the detection range). These drawbacks directly lead to signal distortion, functional failure, and even device damage. The "dynamic range" (DR) of a photodetector is defined as the ratio of the maximum detectable light power to the minimum detectable light power. The shortcomings of overexposure and underexposure are essentially due to the fact that the dynamic range cannot cover the actual power variation of the incident light. Summary of the Invention

[0004] In view of this, the present invention aims to provide a custom pixel dynamic adjustment system and method for germanium-silicon photodetector arrays, to solve the problem that traditional photodetectors, due to their single sampling mode, are prone to overexposure and underexposure in environments with drastic exposure changes, leading to signal distortion or even device damage. The present invention proposes a custom pixel dynamic adjustment method based on germanium-silicon photodetector arrays. This invention adjusts the exposure duration of the next frame image in real time using the previous frame image data, enabling subsequent images to obtain more suitable exposure values, ultimately optimizing image quality and significantly improving the accuracy and stability of photoelectric detection and imaging.

[0005] To achieve the above objectives, the technical solution created by this invention is implemented as follows:

[0006] A custom pixel dynamic adjustment system for a germanium-silicon photodetector array includes a germanium-silicon photodetector array, several transimpedance amplifiers, several high-speed analog-to-digital converters, a sampling and data fusion module, and a dynamic optimization module, wherein:

[0007] The germanium-silicon photodetector array includes an n×t pixel array, with each pixel serving as an independent detector unit. The detector unit, transimpedance amplifier, and high-speed analog-to-digital converter are connected in series. The output of each high-speed analog-to-digital converter is connected to the input of the sampling and data fusion module, and the output of the sampling and data fusion module is connected to the input of the dynamic optimization module.

[0008] The germanium-silicon photodetector array samples the same target scene multiple times with an initial sampling count. The germanium-silicon photodetector array is used to receive the target light signal and convert it into a current signal. The transimpedance amplifier is used to convert the corresponding current signal into a voltage signal and linearly amplify the voltage signal. The high-speed analog-to-digital converter is used to convert the amplified voltage signal into a digital signal. The sampling and data fusion module is used to superimpose the digital signals output by each high-speed analog-to-digital converter pixel by pixel to generate a real-time image. The dynamic optimization module is used to adjust the sampling count pixel by pixel based on the grayscale value matrix of the real-time image to obtain the target image.

[0009] Furthermore, the specific process by which the dynamic optimization module adjusts the sampling frequency pixel-by-pixel based on the grayscale value matrix of the real-time image is as follows:

[0010] Let the initial number of samplings be a, and the grayscale value of each pixel in the real-time image be expressed in b-bit binary. Calculate the reference range m, and adjust the sampling number of each detector unit so that the grayscale value of each detector unit is between 25%m and 75%m to obtain the target image.

[0011] Furthermore, the formula for calculating the reference range m is:

[0012] ;

[0013] Where b is the number of binary bits and m is the reference range.

[0014] A custom pixel dynamic adjustment method based on a germanium-silicon photodetector array is implemented using a custom pixel dynamic adjustment system for the germanium-silicon photodetector array, and specifically includes the following steps:

[0015] S1: The germanium-silicon photodetector array samples the same target scene multiple times with the initial sampling number. The germanium-silicon photodetector array receives the target light signal and converts the target light signal into a current signal.

[0016] S2: The transimpedance amplifier converts the corresponding current signal into a voltage signal and then linearly amplifies the voltage signal;

[0017] S3: The high-speed analog-to-digital converter converts the amplified voltage signal into a digital signal. The sampling and data fusion module superimposes the digital signals output by each high-speed analog-to-digital converter pixel by pixel to generate a real-time image.

[0018] S4: The dynamic optimization module adjusts the number of samplings pixel by pixel based on the gray value matrix of the real-time image, so that the gray value corresponding to each detector unit is between 25%m and 75%m, thereby obtaining the target image;

[0019] S5: Replace the current target scene with the next scene to be detected, and repeat steps S1-S4 to achieve custom pixel dynamic adjustment of the germanium-silicon photodetector array.

[0020] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0021] This invention creates a custom pixel dynamic adjustment system and method for germanium-silicon photodetector arrays. Traditional photodetector systems rely on fixed hardware parameters and can only operate stably within a narrow light intensity range. In low-light environments, the signal is easily masked by noise, leading to a decrease in detection accuracy. In high-light environments, signal saturation and overexposure are prone to occur, and the adjustment method is singular, failing to achieve adaptive adaptation. This invention, through an innovative mechanism of "multiple pixel-by-pixel sampling + custom data overlay," can expand the sampling number of different pixels from 1 to 1024 times according to actual application needs. The custom-overlayed binary data can cover a wider range of optical power—in low-light scenarios, multiple sampling overlays can enhance the effective signal strength and suppress noise interference; in high-light scenarios, reducing the number of samplings can avoid distortion caused by excessive signal overlay. Ultimately, it achieves customizable and adjustable expansion of the dynamic range, adapting to various application scenarios from low light to high light. By utilizing the "adaptive adjustment" closed loop, the first frame image generated by 32 samples is used as a benchmark. The exposure status of each pixel is automatically evaluated by grayscale value. When overexposed, the number of samples is automatically reduced, and when underexposed, the number of samples is automatically increased. This achieves dynamic optimization of the sampling parameters for the next frame, improving the system's response speed and adaptability to changes in light intensity. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 A schematic diagram of the custom pixel dynamic adjustment system for the germanium-silicon photodetector array described in the embodiment of the present invention;

[0024] Figure 2This is a flowchart illustrating the custom pixel dynamic adjustment method for a germanium-silicon photodetector array as described in an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Germanium-silicon photodetector array; 2. Transimpedance amplifier; 3. High-speed analog-to-digital converter; 4. Sampling and data fusion module; 5. Dynamic optimization module. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] like Figure 1As shown, this invention provides a custom pixel dynamic adjustment system for a germanium-silicon photodetector array, comprising a germanium-silicon photodetector array 1, several transimpedance amplifiers 2, several high-speed analog-to-digital converters 3, a sampling and data fusion module 4, and a dynamic optimization module 5, wherein:

[0033] The germanium-silicon photodetector array 1 includes an n×t pixel array, with each pixel serving as an independent detector unit. The detector unit, transimpedance amplifier 2, and high-speed analog-to-digital converter 3 are connected in series. The output of each high-speed analog-to-digital converter 3 is connected to the input of the sampling and data fusion module 4, and the output of the sampling and data fusion module 4 is connected to the input of the dynamic optimization module 5.

[0034] The germanium-silicon photodetector array 1 samples the same target scene multiple times with an initial sampling count. The germanium-silicon photodetector array 1 is used to receive the target light signal and convert the target light signal into a current signal. The transimpedance amplifier 2 is used to convert the corresponding current signal into a voltage signal and linearly amplify the voltage signal. The high-speed analog-to-digital converter 3 is used to convert the amplified voltage signal into a digital signal. The sampling and data fusion module 4 is used to superimpose the digital signals output by each high-speed analog-to-digital converter 3 pixel by pixel to generate a real-time image. The dynamic optimization module 5 is used to adjust the sampling count pixel by pixel based on the gray value matrix of the real-time image to obtain the target image.

[0035] It should be noted that the custom sampling characteristics of the germanium-silicon photodetector array 1 are used to perform adaptive adjustment and dynamic optimization of the image. The number of sampling points of each pixel in the next frame image is adjusted by using the gray values ​​of each pixel in the previous frame image, and finally a dynamic adaptation adjustment closed loop is achieved.

[0036] In some embodiments, the specific process by which the dynamic optimization module 5 adjusts the sampling frequency pixel by pixel based on the grayscale value matrix of the real-time image is as follows:

[0037] Let the initial number of samplings be a, and the grayscale value of each pixel in the real-time image be expressed in b-bit binary. Calculate the reference range m, and adjust the sampling number of each detector unit so that the grayscale value of each detector unit is between 25%m and 75%m to obtain the target image.

[0038] Furthermore, the formula for calculating the reference range m is:

[0039] ;

[0040] Where b is the number of binary bits and m is the reference range.

[0041] (1) Detector array and signal preprocessing module construction: An n×t germanium-silicon photodetector array 1 (n and t are the number of columns and rows of the germanium-silicon photodetector array 1, respectively) is used. Each germanium-silicon photodetector detector unit is an independent pixel, used to receive the target light signal and convert it into an initial current signal. Next, a transimpedance amplifier 2 (TIA) is connected to each detector unit. The weak current signal output by the detector unit is converted into a voltage signal by the transimpedance amplifier 2, and the voltage signal is linearly amplified to ensure that the signal strength meets the subsequent acquisition requirements. A transimpedance amplifier 2 is connected to each germanium-silicon photodetector detector unit to convert the current signal generated by each detector unit into a voltage signal and amplify and output it.

[0042] (2) High-speed signal acquisition and digital conversion: A high-speed analog-to-digital converter 3 (ADC) is connected to the output of each transimpedance amplifier 2. The ADC performs real-time acquisition and digital conversion of the amplified analog voltage signal through the “sample-hold-quantize-encode” process, converting the analog signal into a binary discrete digital signal to ensure the timeliness and accuracy of the signal.

[0043] (3) Single-pixel custom sampling and data fusion:

[0044] ① Single pixel-by-pixel sampling: Simultaneous pixel-by-pixel sampling is performed on n×t pixels to obtain the first set of binary discrete data arranged in pixel order (from left to right, from top to bottom), denoted as {x 11 x 12 x 13 ...x 1n ...x 21 ...x tn}(x ij (Represents the sampled data of the pixel in the i-th row and j-th column).

[0045] ② Multiple pixel-by-pixel sampling and data overlay: Using the same global synchronization method, the same target optical signal is sampled again to obtain a second set of binary discrete data {y 11 y 12 y 13 ...y 1n ...y 21 ...y tn The two sets of data are superimposed pixel by pixel to obtain the grayscale matrix {x} of the real-time image. 11 +y 11 x 12 +y 12 x 13 +y 13 ...x 1n +y 1n ...x 21 +y21 ...x tn +y tn Furthermore, the data between different pixels remains independent of each other;

[0046] ③ Repeat the above sampling and overlay process, setting the number of sampling times to 1, 2, 4, 8, 16, 32... up to 1024 times, respectively, to generate multiple sets of fused binary discrete data for each individual pixel (n×t pixels). Since the more sampling times, the larger the overlay binary value, the wider the range of optical power that can be covered, thereby realizing the custom expansion of the detection dynamic range. At the same time, since the data between each pixel is independent of each other, the number of sampling times for each pixel can be flexibly customized according to the grayscale value of different pixels.

[0047] (4) Adaptability adjustment and dynamic optimization

[0048] ① Initial image generation: Select the fused data corresponding to 32 samples as the benchmark, reconstruct it according to the row and column order of the pixel array, and generate the initial target image (real-time image for the current detection scene).

[0049] ② Dynamic sampling number control: Exposure evaluation is performed based on the gray value distribution of the initial target image, and a feedback control mechanism is established.

[0050] For each pixel in the initial target image, determine whether there is overexposure or underexposure based on its grayscale value: if there is underexposure, increase the sampling count of that pixel; if there is overexposure, decrease the sampling count of that pixel, and so on, to complete the custom adjustment of the sampling count of all pixels in the entire image.

[0051] ③ Achieved effect: Through the closed-loop process of "image evaluation - parameter adjustment - resampling", the detection system achieves adaptive optimization of the dynamic range of each pixel, ensuring that clear and distortion-free target images can be output under different light intensity conditions.

[0052] Each pixel is sampled several times according to the initial sampling count to generate a grayscale matrix. Then, the grayscale value of each pixel is compared with the expected value (25%-75% of the total range) to evaluate whether it meets the expected requirements (image evaluation). Based on the evaluation feedback, the sampling count of each pixel is adjusted (parameter adjustment) to bring the grayscale value of each pixel into the expected range. Finally, a second set of data is collected based on the adjusted sampling count for each pixel to generate the target image (resampling).

[0053] For example, a 2×2 area array detector uses 8-bit data to represent grayscale values. The first sampling is performed 16 times to obtain the grayscale matrix of the real-time image. According to the above evaluation rules, the pixel corresponding to

[30] is underexposed, so its next sampling count is adjusted to 64 times; the pixel corresponding to

[250] is overexposed, so its next sampling count is adjusted to 12 times; the sampling counts of other pixels remain unchanged, and the grayscale matrix of the target image is obtained. .

[0054] like Figure 2 As shown, this invention provides a custom pixel dynamic adjustment method for a germanium-silicon photodetector array, which is implemented using a custom pixel dynamic adjustment system for the germanium-silicon photodetector array, and specifically includes the following steps:

[0055] S1: The germanium-silicon photodetector array 1 samples the same target scene multiple times under the initial sampling number. The germanium-silicon photodetector array 1 receives the target light signal and converts the target light signal into a current signal.

[0056] S2: Transimpedance amplifier 2 converts the corresponding current signal into a voltage signal and linearly amplifies the voltage signal;

[0057] S3: The high-speed analog-to-digital converter 3 converts the corresponding amplified voltage signal into a digital signal. The sampling and data fusion module 4 superimposes the digital signals output by each high-speed analog-to-digital converter 3 pixel by pixel to generate a real-time image.

[0058] S4: The dynamic optimization module 5 adjusts the number of samplings pixel by pixel based on the gray value matrix of the real-time image, so that the gray value corresponding to each detector unit is between 25%m and 75%m, and the target image is obtained.

[0059] Let the initial number of samplings be a, and the grayscale value of each pixel in the real-time image be expressed in b-bit binary. Calculate the reference range m, and adjust the sampling number of each detector unit so that the grayscale value of each detector unit is between 25%m and 75%m to obtain the target image.

[0060] The formula for calculating the reference range m is:

[0061] ;

[0062] Where b is the number of binary bits and m is the reference range.

[0063] S5: Replace the current target scene with the next scene to be detected, and repeat steps S1-S4 to achieve custom pixel dynamic adjustment of germanium-silicon photodetector array 1.

[0064] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0065] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A custom pixel dynamic adjustment method based on a germanium-silicon photodetector array, implemented using a custom pixel dynamic adjustment system for the germanium-silicon photodetector array, characterized in that: The system includes a germanium-silicon photodetector array, several transimpedance amplifiers, several high-speed analog-to-digital converters, a sampling and data fusion module, and a dynamic optimization module, wherein: The germanium-silicon photodetector array includes an n×t pixel array, with each pixel serving as an independent detector unit. The detector unit, transimpedance amplifier, and high-speed analog-to-digital converter are connected in series. The output of each high-speed analog-to-digital converter is connected to the input of the sampling and data fusion module, and the output of the sampling and data fusion module is connected to the input of the dynamic optimization module. The germanium-silicon photodetector array samples the same target scene multiple times with an initial sampling count. The germanium-silicon photodetector array is used to receive the target light signal and convert it into a current signal. The transimpedance amplifier is used to convert the corresponding current signal into a voltage signal and linearly amplify the voltage signal. The high-speed analog-to-digital converter is used to convert the amplified voltage signal into a digital signal. The sampling and data fusion module is used to superimpose the digital signals output by each high-speed analog-to-digital converter pixel by pixel to generate a real-time image. The dynamic optimization module is used to adjust the sampling count pixel by pixel based on the gray value matrix of the real-time image to obtain the target image. The specific process by which the dynamic optimization module adjusts the sampling frequency pixel-by-pixel based on the grayscale value matrix of the real-time image is as follows: Let the initial number of samplings be a, and the gray value of each pixel in the real-time image be expressed in b-bit binary. Calculate the reference range m, and adjust the number of samplings for each detector unit so that the gray value corresponding to each detector unit is between 25%m and 75%m to obtain the target image. The formula for calculating the reference range m is: ； Where b is the number of binary bits, and m is the reference range; The method specifically includes the following steps: S1: The germanium-silicon photodetector array samples the same target scene multiple times with the initial sampling count. The germanium-silicon photodetector array receives the target optical signal and converts the target optical signal into a current signal. S2: The transimpedance amplifier converts the corresponding current signal into a voltage signal and then linearly amplifies the voltage signal; S3: The high-speed analog-to-digital converter converts the amplified voltage signal into a digital signal. The sampling and data fusion module superimposes the digital signals output by each high-speed analog-to-digital converter pixel by pixel to generate a real-time image. S4: The dynamic optimization module adjusts the number of samplings pixel by pixel based on the gray value matrix of the real-time image, so that the gray value corresponding to each detector unit is between 25%m and 75%m, thereby obtaining the target image; S5: Replace the current target scene with the next scene to be detected, and repeat steps S1-S4 to achieve custom pixel dynamic adjustment of the germanium-silicon photodetector array.

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