Quantum efficiency acquisition method and system and electronic equipment

Abstract

The invention provides a quantum efficiency obtaining method and system and electronic equipment, and belongs to the technical field of image sensor testing and data analysis, and the quantum efficiency obtaining method comprises the steps: collecting multi-frame original image data; averaging each pixel value of each pixel point in the multi-frame original image data to obtain average frame image data; averaging pixel values of all pixel points in the test area in the average frame image data to obtain an average pixel value of an average frame; the ratio of the first difference value of the average pixel values of the average frames under the two test exposure times to the second difference value of the two test exposure times is used as the responsivity of the image sensor; and acquiring the actual photoelectric responsivity and quantum efficiency of the image sensor according to the responsivity of the image sensor, the irradiance of the incident light and the conversion gain of the image sensor. According to the quantum efficiency acquisition method, the quantum efficiency acquisition system and the electronic equipment provided by the invention, the test precision of the quantum efficiency can be improved.

Description

Technical Field

[0001] This invention belongs to the field of image sensor testing and data analysis technology, and specifically relates to a method, system and electronic device for obtaining quantum efficiency. Background Technology

[0002] In the research and testing of image sensors, quantum efficiency (QE) is a crucial indicator for evaluating the photoelectric conversion performance of image sensors. Quantum efficiency testing systems often rely on manual operation of monochromators, filters, and light source control, resulting in low testing efficiency, large wavelength switching errors, and poor repeatability and reliability of test results. Furthermore, quantum efficiency is typically calculated based on the average value of a single frame, which fails to effectively distinguish between random noise and the true response, making it difficult to guarantee data stability. More critically, the commonly used light-dark method for obtaining quantum efficiency is susceptible to dark field drift, light source fluctuations, and noise superposition, thus reducing test accuracy. Summary of the Invention

[0003] The purpose of this invention is to provide a method, system, and electronic device for obtaining quantum efficiency, which can solve the problems of low stability of quantum data and low accuracy of efficiency testing.

[0004] To achieve the above objective, the present invention provides a method for obtaining quantum efficiency, comprising at least the following steps:

[0005] Set at least two test exposure times, and acquire multiple frames of raw image data at each set wavelength and each test exposure time;

[0006] Obtain the pixel value of each pixel in each frame of raw image data, and average the pixel values ​​of each pixel across multiple frames of raw image data to obtain the average frame image data;

[0007] Define a test area, and average the pixel values ​​of all pixels in the test area in the average frame image data to obtain the average pixel value of the average frame.

[0008] The ratio of the first difference in the average pixel values ​​of the average frames under two test exposure times to the second difference in the two test exposure times is taken as the responsivity of the image sensor; and

[0009] Based on the responsivity of the image sensor, the irradiance of the incident light, and the conversion gain of the image sensor, the actual photoelectric responsivity of the image sensor is obtained, and the ratio of the actual photoelectric responsivity to the theoretical responsivity is taken as the quantum efficiency.

[0010] In one embodiment of the present invention, setting the test exposure time includes the following steps:

[0011] At the wavelength with the highest output optical power, the maximum test exposure time for the image to be in an unsaturated state was obtained; and

[0012] At least two of the test exposure times are selected, and the test exposure times are less than the maximum test exposure time.

[0013] In one embodiment of the present invention, obtaining the irradiance of the incident light at each set wavelength includes the following steps:

[0014] A photodetector is placed in the test optical path, and the photocurrent of the photodetector at the set wavelength is measured; and

[0015] The irradiance of the incident light is obtained based on the effective light-receiving area and sensitivity of the photodetector.

[0016] In one embodiment of the present invention, the irradiance of the incident light is obtained according to the following formula:

[0017]

[0018] Where E(λ) is the irradiance of the incident light, and λ is the wavelength of the incident light, I PD For photocurrent, S PD To maximize the effective light-receiving area, PD std (λ) represents the sensitivity.

[0019] In one embodiment of the present invention, the conversion gain of the image sensor is obtained through the following steps:

[0020] At multiple test exposure times within a preset wavelength, multiple frames of raw image data are acquired at each test exposure time.

[0021] At each test exposure time, the pixel value of each pixel in each frame of raw image data is obtained, and the pixel values ​​of each pixel in multiple frames of raw image data are averaged to obtain the average frame image data;

[0022] Obtain the pixel variance between the pixel value of each pixel in each frame of raw image data and the pixel value of each pixel in the average frame image data;

[0023] Define a test area, average the pixel values ​​of all pixels in the test area in the average frame image data to obtain the average pixel value of the average frame, and obtain the median value of the pixel variance of all pixels in the test area.

[0024] At each test exposure time, a point is determined with the average pixel value of the average frame on the horizontal axis and the median value of the pixel variance on the vertical axis. A linear fit is then performed on multiple points determined by the average pixel value of the average frame and the median value of the pixel variance at multiple test exposure times to obtain a linear slope; and

[0025] The reciprocal of the linear slope is used as the conversion gain of the image sensor.

[0026] In one embodiment of the present invention, the actual photoelectric responsivity is obtained by the following formula:

[0027]

[0028] Among them, R real ΔDN is the actual photoelectric responsivity of the image sensor, q is the electron charge constant, ΔDN is the difference in average pixel values ​​of the average frames under two test exposure times, ΔT is the difference in two test exposure times, ΔDN / ΔT is the responsivity of the image sensor, and k is the image sensor's responsivity. ADC For conversion gain, S pix E(λ) represents the effective photosensitive area of ​​a single pixel, and E(λ) represents the irradiance of the incident light.

[0029] In one embodiment of the present invention, a set of test exposure times is selected, and there are two test exposure times in the set of test exposure times. Under the selected set of test exposure times, the quantum efficiency of the image sensor at each set wavelength is obtained, and a quantum efficiency versus wavelength relationship curve is obtained.

[0030] In one embodiment of the present invention, multiple sets of test exposure times are obtained, and under each set of test exposure times, the quantum efficiency of the image sensor at each set wavelength is obtained, and multiple quantum efficiency versus wavelength curves corresponding to the multiple sets of test exposure times are obtained.

[0031] The present invention also provides a system for obtaining quantum efficiency, comprising:

[0032] The raw image data acquisition module acquires multiple frames of raw image data at each set wavelength and each test exposure time;

[0033] The average frame image data acquisition module acquires the pixel value of each pixel in each frame of raw image data, and averages the pixel values ​​of each pixel in multiple frames of raw image data to obtain the average frame image data.

[0034] The average pixel value acquisition module of the average frame delineates a test area and averages the pixel values ​​of all pixels in the test area in the average frame image data to obtain the average pixel value of the average frame.

[0035] The responsivity acquisition module uses the ratio of a first difference in the average pixel values ​​of the average frames under two test exposure times to a second difference in the two test exposure times as the responsivity of the image sensor; and

[0036] The quantum efficiency acquisition module obtains the actual photoelectric responsivity of the image sensor based on the responsivity of the image sensor, the irradiance of the incident light, and the conversion gain of the image sensor, and uses the ratio of the actual photoelectric responsivity to the theoretical responsivity as the quantum efficiency.

[0037] The present invention also provides an electronic device, the electronic device comprising:

[0038] A memory, wherein program instructions are stored; and

[0039] The processor executes program instructions in the memory to implement the quantum efficiency acquisition method described in any of the above.

[0040] In summary, the quantum efficiency acquisition method, system, and electronic device provided by this invention, based on the test exposure time difference method, can accurately acquire the true light response curve by collecting the signal slope changes of the image sensor under different test exposure times. This effectively reduces measurement errors caused by dark field noise instability and minor fluctuations in external light intensity, and significantly improves the linear consistency of data throughout the dynamic range. Secondly, the quantum efficiency acquisition system provided in this application can automatically acquire multiple frames of raw image data. Under strictly controlled lighting conditions, it can continuously capture multiple sets of raw image data at preset time intervals and exposure combinations. Pixel-level averaging is performed on multiple frames of images under the same exposure conditions to reduce random noise. By comparing the signal intensity differences of corresponding pixels under different test exposure times, combined with known lighting parameters, the photoelectric responsivity at each wavelength is obtained. Finally, based on the conversion relationship between photoelectric responsivity and spectral radiance, combined with sensor physical parameters such as pixel area and quantum efficiency curve shape, the quantum efficiency values ​​at different wavelengths are obtained. In the process of acquiring quantum efficiency, variables introduced by human operation are reduced, achieving higher system stability, stronger environmental robustness, and more reliable measurement results. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the quantum efficiency testing device in one embodiment of the present invention.

[0043] Figure 2 This is a flowchart of a method for obtaining quantum efficiency in one embodiment of the present invention.

[0044] Figure 3 This is a flowchart of a method for setting test exposure time in one embodiment of the present invention.

[0045] Figure 4 This is a flowchart of a method for obtaining the irradiance of incident light in one embodiment of the present invention.

[0046] Figure 5 This is a flowchart of a method for obtaining conversion gain in one embodiment of the present invention.

[0047] Figure 6 This is a schematic diagram of the structure of a quantum efficiency acquisition system according to an embodiment of the present invention.

[0048] Figure 7 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0049] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0050] 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 application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0051] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," and "right," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or component 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 of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] Please see Figure 1As shown, the quantum efficiency testing device provided in this application uses a xenon lamp light source 101 and a monochromator 102 to form an optical control module during quantum efficiency testing. This optical control module provides multiple wavelengths of light to the image sensor chip 109. The light source power supply 103 powers the xenon lamp light source 101 and uses a curved mirror 104 to converge and collimate the light emitted by the xenon lamp light source 101. Then, the incident light is filtered by a filter assembly 105, and the output light intensity is adjusted as needed using a light attenuation controller 106. Simultaneously, a wavelength scanning and filter switcher 107 works with the monochromator 102 to perform wavelength switching operations, and the emitting optical unit 108 can perform optical path shaping and transmission of specific wavelength light output from the monochromator 102.

[0053] Please see Figure 1 As shown, when using the quantum efficiency testing device provided in this application to test the quantum efficiency of the image sensor chip 109, the image sensor chip 109 to be tested is fixedly mounted on the component fixing platform 110, and the fixing platform 110 is set in the dark chamber 100 to eliminate ambient light interference. Through the control program running on the control device 111, the monochromator 102 is driven to perform automatic wavelength scanning, and at each target wavelength, the image acquisition device 112 is controlled to acquire multiple frames of raw image data output by the image sensor chip 109 in multi-exposure mode. In addition, a photocurrent meter 113 and a digital multimeter 114 are provided to read the photocurrent signal.

[0054] Please combine Figure 1 and Figure 2 As shown, based on the quantum efficiency testing device provided above, this application provides a method for obtaining quantum efficiency, which is implemented using the aforementioned quantum efficiency testing device. Specifically, the method for obtaining quantum efficiency provided by this application includes steps S110 to S150.

[0055] Step S110: Set at least two test exposure times, and acquire multiple frames of raw image data at each set wavelength and each test exposure time.

[0056] Step S120: Obtain the pixel value of each pixel in each frame of original image data, and average the pixel values ​​of each pixel in multiple frames of original image data to obtain average frame image data.

[0057] Step S130: Define the test area, and average the pixel values ​​of all pixels in the test area in the average frame image data to obtain the average pixel value of the average frame.

[0058] Step S140: The ratio of the first difference of the average pixel value of the average frame under the two test exposure times to the second difference of the two test exposure times is used as the responsivity of the image sensor chip.

[0059] Step S150: Based on the responsivity of the image sensor chip, the irradiance of the incident light, and the conversion gain of the image sensor chip, obtain the actual photoelectric responsivity of the image sensor chip, and use the ratio of the actual photoelectric responsivity to the theoretical responsivity as the quantum efficiency.

[0060] Please see Figure 2 and Figure 3 As shown, in one embodiment of the present invention, when setting the test exposure time, in order to ensure that the acquired image is not overexposed, thereby ensuring the acquisition of effective linear response data and accurate quantum efficiency, it is necessary to limit the set test exposure time. In this embodiment, setting the test exposure time includes steps S111 to S112.

[0061] Step S111: At the wavelength with the highest output light power, obtain the maximum test exposure time when the image is in an unsaturated state.

[0062] Specifically, if the exposure wavelength range of the image sensor chip is, for example, 300nm to 1000nm, and the wavelength with the highest output light power is, for example, 470nm, then the maximum test exposure time T for obtaining an image in an unsaturated state under light at a wavelength of 470nm is... max In this application, at the wavelength with the highest output optical power, it is necessary to ensure that the maximum test exposure time T is maintained. max The average pixel value of the captured image does not exceed 75% of the maximum pixel value, thus avoiding entering the saturation region.

[0063] Step S112: Select at least two test exposure times, and the test exposure times are less than the maximum test exposure time.

[0064] Specifically, when selecting test exposure times, the number of test exposure times can be determined based on the number of quantum efficiency versus wavelength curves that need to be obtained. When only one quantum efficiency versus wavelength curve is needed, two test exposure times are selected, for example, a first test exposure time and a second test exposure time. The difference between the average pixel value of the average frame at the first test exposure time and the average pixel value of the average frame at the second test exposure time is used as the first difference, and the difference between the first test exposure time and the second test exposure time is used as the second difference required subsequently. When two quantum efficiency versus wavelength curves are needed, three or four test exposure times can be selected. When three test exposure times are selected, such as the first, second, and third test exposure times, the difference between the average pixel value of the average frame at the first and second test exposure times, and the difference between the average pixel value of the average frame at the first and third test exposure times, are used as the first difference. The difference between the first and second test exposure times, and the difference between the first and third test exposure times, are used as the second difference. When four test exposure times are selected, such as the first, second, third, and fourth test exposure times, the difference between the average pixel value of the average frame at the first and second test exposure times, and the difference between the average pixel value of the average frame at the third and fourth test exposure times, are used as the first difference. The difference between the first and second test exposure times, and the difference between the third and fourth test exposure times, are used as the second difference.

[0065] Therefore, in this application, the number of test exposure times can be selected according to actual needs, ensuring that each test exposure time is less than the maximum test exposure time. That is, in the above embodiment, the first, second, third, and fourth test exposure times are all less than the maximum test exposure time T. max When the test exposure time is less than the maximum test exposure time T max This ensures that none of the captured images will be overexposed.

[0066] Please see Figure 2 As shown, in one embodiment of the present invention, after obtaining the test exposure time, multiple frames of raw image data are acquired at each set wavelength and each test exposure time. Then, for the multiple frames of raw image data acquired at each set wavelength and each test exposure time, steps S120 to S130 are executed.

[0067] Please see Figure 2 As shown, in one embodiment of the present invention, for multiple frames of raw image data acquired at each set wavelength and each test exposure time, step S120 is first executed to obtain the pixel value of each pixel in each frame of raw image data, and the pixel values ​​of each pixel in the multiple frames of raw image data are averaged to obtain average frame image data. Specifically, the pixel value of each pixel in each frame of raw image data is defined as:

[0068] DN i (x, y);

[0069] Where (x, y) are the pixel coordinates of the pixel points in each frame of the original image data, i represents the frame number, and the value of i is 1, 2, ..., N-1, N, where N is the total number of frames.

[0070] At this point, the pixel value in the first row and first column of the first frame is DN1(1,1), and the pixel value in the eleventh row and thirteenth column of the third frame is DN3(11,13).

[0071] The average pixel value of each pixel in the multiple frames of original image data is then calculated using the following formula:

[0072]

[0073] in, y is the pixel value of the pixel point (x, y) in the average frame image data.

[0074] At this point, the pixel value of each pixel in the acquired average frame image data is equal to the average of the pixel values ​​of the corresponding pixels in all the original multi-frame image data.

[0075] In a specific embodiment of the present invention, for example, 10 frames of raw image data are acquired at a first test exposure time T1 at a wavelength of, for example, 470nm. Then, an average frame image data is obtained for these 10 frames of raw image data. The pixel value of each pixel in the average frame image data is equal to the average of the pixel values ​​of the corresponding 10 pixels in the 10 frames of raw image data. At this time, the pixel value of the first row and first column of the average frame image data is equal to the pixel value of the first row and first column of the first frame of raw image data, the pixel value of the first row and first column of the second frame of raw image data, ..., the pixel value of the first row and first column of the ninth frame of raw image data, and the average of the pixel values ​​of the first row and first column of the tenth frame of raw image data.

[0076] Please see Figure 2As shown, in one embodiment of the present invention, after acquiring the average frame image data, a test area is defined. The location and size of the defined test area are set according to requirements. In this embodiment, the defined test area is, for example, a 200×200 pixel range centered on the data center point of each frame image data.

[0077] Please see Figure 2 As shown, in one embodiment of the present invention, after defining the test area, the pixel values ​​of all pixels within the test area are averaged in the average frame image data to obtain the average pixel value of the average frame. Specifically, the pixel values ​​of all pixels within a 200×200 pixel range centered on the average frame image data center are averaged to obtain the average pixel value of the average frame. The average pixel value of the average frame is obtained using the following formula:

[0078]

[0079] in, Ω represents the average pixel value of the average frame, Ω represents the number of pixels in the test area, and |Ω| represents the total number of pixels in the test area.

[0080] In this application, the average pixel value of the average frame is used as the input parameter for subsequent photoelectric responsivity calculation. This can exclude unevenly lit areas at the edges and select representative effective areas to ensure the spatial consistency and reliability of the photoelectric responsivity calculation results.

[0081] Please see Figure 2 As shown, in one embodiment of the present invention, through steps S120 and S130, the average value of multiple frames of original image data under each set wavelength and each test exposure time can be obtained. At this time, the average value of two average frames obtained under one set wavelength and two test exposure times is selected. Step S140 is executed, and the ratio of the first difference of the average pixel values ​​of the average frames under the two test exposure times to the second difference of the two test exposure times is used as the responsivity of the image sensor chip. The responsivity of the image sensor chip is then obtained using the following formula:

[0082]

[0083] in, This represents the average pixel value of the average frame during the first test exposure time. Let T2 be the average pixel value of the average frame under the second test exposure time, and T1 be the first test exposure time. T1 is the first difference, and T2-T1 is the second difference.

[0084] In this application, the change in photocurrent is calculated by the exposure difference method, which effectively eliminates the influence of dark current and fixed bias, thereby more accurately reflecting the chip's true electrical response capability to changes in illumination.

[0085] Please see Figure 2 As shown, in one embodiment of the present invention, after obtaining the responsivity of the image sensor chip, the actual photoelectric responsivity of the image sensor chip is obtained based on the responsivity of the image sensor chip, the irradiance of the incident light, and the conversion gain of the image sensor chip. The ratio of the actual photoelectric responsivity to the theoretical responsivity is then used as the quantum efficiency. The irradiance of the incident light and the conversion gain of the image sensor chip can be obtained using conventional methods. For example, the irradiance of the incident light can be obtained using methods such as direct measurement with a standard optical power meter and indirect calibration. The conversion gain of the image sensor chip can be obtained using methods such as photon transfer curve method or photocurrent-signal value calibration method.

[0086] Please see Figure 1 , Figure 2 and Figure 4 As shown, in one embodiment of the present invention, before obtaining the responsivity of the image sensor chip, the control device 111 first controls the monochromator 102 to output stable narrowband light according to a predetermined wavelength range and step, and simultaneously controls the filter switching and light intensity stabilization module to ensure the consistency of spectral purity and luminous flux under different wavelength bands. This is used to provide monochromatic incident light of different wavelengths to the image sensor chip 109, establishing the correspondence between wavelength and photoelectric response, which is the starting condition for quantum efficiency testing. The predetermined wavelength range is the exposure wavelength range of the image sensor chip 109, for example, 300nm to 1000nm, and the step is, for example, 10nm. At each set wavelength, the irradiance of the incident light can be obtained first. The acquisition of the irradiance of the incident light at each set wavelength includes steps S201 to S202.

[0087] Step S201: Place a photodetector in the test optical path and test the photocurrent of the photodetector at a set wavelength.

[0088] Step S202: Obtain the irradiance of the incident light based on the effective light-receiving area and sensitivity of the photodetector.

[0089] Specifically, the irradiance of the incident light is obtained according to the following formula:

[0090]

[0091] Where E(λ) is the irradiance of the incident light, and λ is the wavelength of the incident light, I PD For photocurrent, S PD To maximize the effective light-receiving area, PD std (λ) represents the sensitivity.

[0092] In this application, the irradiance of the incident light is acquired before the responsivity of the image sensor chip is acquired. Furthermore, an irradiance value needs to be acquired at each set wavelength to provide reference optical power data for the photoelectric responsivity of the image sensor chip, enabling energy calibration at different wavelengths. After acquiring the irradiance of the incident light, the photodetector can be removed, and the image sensor chip under test can be positioned on the same optical axis.

[0093] Please see Figure 2 and Figure 5 As shown, in one embodiment of the present invention, each image sensor chip is provided with a corresponding conversion gain, and the conversion gain of the image sensor chip can be obtained synchronously with the responsivity of the image sensor chip. Specifically, the method for obtaining the conversion gain of the image sensor chip includes steps S301 to S306.

[0094] Step S301: Acquire multiple frames of raw image data at each test exposure time under multiple test exposure times at a preset wavelength.

[0095] Specifically, the preset wavelength can be any wavelength within the exposure wavelength range of the image sensor chip, such as 470nm. During the acquisition of conversion gain, the test exposure time is within the sensitive linear time of the image sensor chip.

[0096] Step S302: At each test exposure time, obtain the pixel value of each pixel in each frame of raw image data, and average the pixel values ​​of each pixel in multiple frames of raw image data to obtain average frame image data.

[0097] Step S303: Obtain the pixel value of each pixel in the original image data of each frame and the pixel variance of each pixel in the average frame image data.

[0098] Specifically, the pixel variance between the pixel value of each pixel in each frame of raw image data and the pixel value of each pixel in the average frame of image data is obtained using the following formula:

[0099]

[0100] Among them. Var i (x,y) represents the variance at pixel (x,y) in the original image data of the i-th frame, DN i (x, y) represents the pixel value of each pixel in each frame of the original image data. y is the pixel value of the pixel point (x, y) in the average frame image data.

[0101] Step S304: Define the test area, average the pixel values ​​of all pixels in the test area in the average frame image data to obtain the average pixel value of the average frame, and obtain the median value of the pixel variance of all pixels in the test area.

[0102] Specifically, the median value of the pixel variance of all pixels within the test area is obtained using the following formula:

[0103]

[0104] in. This is the median value of the pixel variance of all pixels in the test area. median(·) means taking the median value.

[0105] Step S305: At each test exposure time, determine a point with the average pixel value of the average frame on the horizontal axis and the median value of the pixel variance on the vertical axis. Perform linear fitting on multiple points determined by the average pixel value of the average frame and the median value of the pixel variance at multiple test exposure times to obtain the linear slope.

[0106] Step S306: Use the reciprocal of the linear slope as the conversion gain of the image sensor chip.

[0107] Specifically, under multiple test exposure times at a preset wavelength, a graph is plotted with the average pixel value of the average frame on the horizontal axis and the median pixel variance on the vertical axis. A non-saturated linear response interval is selected, and its linear slope S is fitted. The conversion gain is then obtained using the following formula:

[0108]

[0109] Where, k ADC This is the conversion gain, and the unit of conversion gain is e. - / DN, which stands for the number of electrons corresponding to each digital unit (DN). Obtaining the conversion gain establishes the proportional relationship between the pixel digital output and the actual number of electrons, reflecting the signal conversion capability of the image sensor chip.

[0110] In this application, the median value of the pixel variance of all pixels within the test area is selected as the standard for obtaining the conversion gain of the image sensor chip. When evaluating system noise levels and pixel stability, the median variance exhibits strong robustness and can avoid bias caused by isolated abnormal pixels. Obtaining the conversion gain of the image sensor chip establishes a proportional relationship between the pixel digital output and the actual number of electrons, reflecting the signal conversion capability of the image sensor chip.

[0111] Please see Figure 2As shown, in one embodiment of the present invention, after obtaining the responsivity of the image sensor chip, the irradiance of the incident light, and the conversion gain of the image sensor chip, the actual photoelectric responsivity of the image sensor chip is obtained based on the responsivity, the irradiance of the incident light, and the conversion gain of the image sensor chip. The actual photoelectric responsivity of the image sensor chip is then obtained using the following formula:

[0112]

[0113] Among them, R real Here, represents the actual photoelectric responsivity of the image sensor chip, and q is the electron charge constant, with a value of 1.602 × 10⁻⁶. -19 C, ΔDN is the difference in average pixel values ​​of the average frames under two test exposure times, ΔT is the difference in exposure times between the two tests, ΔDN / ΔT is the responsivity of the image sensor chip, k ADC For conversion gain, S pix E(λ) represents the effective photosensitive area of ​​a single pixel, and E(λ) represents the irradiance of the incident light, i.e., the incident light power density illuminating the chip surface.

[0114] In this application, the actual photoelectric responsivity of the image sensor chip obtained integrates key parameters such as pixel charge conversion efficiency, exposure control, and light input energy, and can accurately characterize the actual photoelectric response capability of the chip.

[0115] Under ideal conditions, when the quantum efficiency QE = 100%, the theoretical responsivity is obtained by the following formula:

[0116]

[0117] Among them, R ideal Here, λ is the theoretical responsivity, q is the electron charge constant, λ is the wavelength of the incident light, h is Planck's constant, and c is the speed of light.

[0118] The quantum efficiency of an image sensor chip at a given wavelength λ can be obtained using the following formula:

[0119]

[0120] This application compares the actual photoelectric response of an image sensor chip with its theoretical full-efficiency state when obtaining quantum efficiency, thus obtaining the quantum conversion efficiency of the image sensor chip at various wavelengths. This is the core result characterizing the chip's photoelectric performance. The quantum efficiency acquisition method provided by this invention utilizes statistical averaging and median variance analysis of multiple frames of raw image data to effectively suppress random noise and abnormal pixel interference, improving the accuracy and stability of conversion gain estimation, thereby obtaining more accurate and robust photoelectric responsivity and quantum efficiency test results.

[0121] Please combine Figure 2 As shown, in one embodiment of the present invention, two test exposure times are set to form a set of test exposure times. When obtaining the quantum efficiency versus wavelength curve, a set of test exposure times is first selected, and this set contains two test exposure times. Under the selected set of test exposure times, the quantum efficiency of the image sensor chip at each set wavelength is obtained, thus obtaining a quantum efficiency versus wavelength curve. Then, multiple sets of test exposure times are obtained, and under each set of test exposure times, the quantum efficiency of the image sensor chip at each set wavelength is obtained, resulting in multiple quantum efficiency versus wavelength curves corresponding to multiple sets of test exposure times. At this point, the multiple quantum efficiency versus wavelength curves corresponding to multiple sets of test exposure times should be nearly identical. If one or more points in a quantum efficiency versus wavelength curve do not match other quantum efficiency versus wavelength curves, then there is an anomaly in the current quantum efficiency versus wavelength curve.

[0122] Please see Figure 6As shown, this application also provides a quantum efficiency acquisition system, which can be installed in the control device 111 of the quantum efficiency measurement device. The quantum efficiency acquisition system includes at least a test exposure time limiting module 201, a raw image data acquisition module 202, an average frame image data acquisition module 203, an average pixel value acquisition module 204, a responsivity acquisition module 205, an incident light irradiance acquisition module 206, a conversion gain acquisition module 207, and a quantum efficiency acquisition module 208. The test exposure time limiting module 201 sets at least two test exposure times, specifically executing steps S111 and S112. The raw image data acquisition module 202 acquires multiple frames of raw image data at each set wavelength and each test exposure time. At this time, the raw image data acquisition module 202 specifically executes step S110. The average frame image data acquisition module 203 acquires the pixel value of each pixel in each frame of raw image data and averages the pixel values ​​of each pixel across multiple frames of raw image data to obtain average frame image data. At this time, the average frame image data acquisition module 203 specifically executes the content of step S120. The average pixel value acquisition module 204 of the average frame delineates the test area and averages the pixel values ​​of all pixels in the test area in the average frame image data to obtain the average pixel value of the average frame. At this time, the average pixel value acquisition module 204 of the average frame specifically executes the content of step S120. The responsivity acquisition module 205 uses the ratio of the first difference of the average pixel values ​​of the average frames under two test exposure times to the second difference of the two test exposure times as the responsivity of the image sensor chip 109. At this time, the responsivity acquisition module 205 specifically executes the content of steps S201 and S202. The incident light irradiance acquisition module 206 acquires the incident light irradiance. The conversion gain acquisition module 207 acquires the incident light irradiance. At this time, the conversion gain acquisition module 207 specifically executes the content of steps S301 to S306. The quantum efficiency acquisition module 208 obtains the actual photoelectric responsivity of the image sensor chip 109 based on the responsivity, the irradiance of the incident light, and the conversion gain of the image sensor chip 109, and uses the ratio of the actual photoelectric responsivity to the theoretical responsivity as the quantum efficiency. At this time, the quantum efficiency acquisition module 208 specifically executes the content of step 150.

[0123] Please see Figure 6As shown, the quantum efficiency acquisition module 208 of the quantum efficiency acquisition system provided in this application can automatically output data such as the irradiance of incident light at each wavelength, the actual photoelectric responsivity, theoretical responsivity and quantum efficiency data of the image sensor chip, and save the data such as the irradiance of incident light at each wavelength, the actual photoelectric responsivity, theoretical responsivity and quantum efficiency data of the image sensor chip as an Excel file and generate a quantum efficiency spectrum curve, that is, the relationship curve between quantum efficiency and wavelength, realizing the automatic organization and visualization of the results, which is convenient for subsequent data analysis and comparison of the spectral performance of the image sensor chip.

[0124] Please see Figure 7 As shown, the present invention also provides an electronic device, which includes a memory 302 and a processor 301. The memory 302 stores program instructions, and the processor 301 executes the program instructions in the memory 302 to implement the quantum efficiency acquisition method described above.

[0125] Please see Figure 7 As shown, the memory 302 includes at least one type of readable storage medium, including flash memory, portable hard drive, multimedia card, card-type memory (e.g., SD or DX memory), magnetic memory, magnetic disk, optical disk, etc. In some embodiments, the memory can be an internal storage unit of an electronic device, such as a portable hard drive. In other embodiments, the memory can be an external storage device of the electronic device, such as a plug-in portable hard drive, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, etc. Furthermore, the memory can include both internal and external storage units of the electronic device. The memory can be used not only to store application software and various types of data installed on the electronic device, but also to temporarily store data that has been output or will be output.

[0126] Please see Figure 7 As shown, in some embodiments, the processor 301 may be composed of integrated circuits, such as a single packaged integrated circuit or multiple integrated circuits packaged with the same or different functions, including combinations of one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and various control chips. The processor is the control unit of the host, executing various functions and processing data of the host by running or executing programs or modules stored in the memory and calling data stored in the memory.

[0127] The processor executes the host's operating system and various installed applications. The processor executes the applications to implement the steps in the above method embodiments.

[0128] For example, the program can be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules can be a series of program instruction segments capable of performing a specific function, which describe the execution process of the program on the host.

[0129] The integrated unit, implemented as a software functional module, can be stored in a computer-readable storage medium. This software functional module, stored in a storage medium, includes several instructions to cause a computer device (which may be a personal computer, a computer device, or a network device, etc.) or processor to execute some functions of the quantum efficiency acquisition method of the various embodiments of the present invention.

[0130] In summary, the method for obtaining quantum efficiency provided by this invention includes the following steps: setting at least two test exposure times, and acquiring multiple frames of raw image data at each set wavelength and each test exposure time. Acquiring the pixel value of each pixel in each frame of raw image data, and averaging the pixel values ​​of each pixel across the multiple frames of raw image data to obtain average frame image data. Delineating a test area, and averaging the pixel values ​​of all pixels within the test area in the average frame image data to obtain the average pixel value of the average frame. Using the ratio of a first difference between the average pixel values ​​of the average frames under the two test exposure times to a second difference between the two test exposure times as the responsivity of the image sensor chip. Based on the responsivity of the image sensor chip, the irradiance of the incident light, and the conversion gain of the image sensor chip, obtaining the actual photoelectric responsivity of the image sensor chip, and using the ratio of the actual photoelectric responsivity to the theoretical responsivity as the quantum efficiency.

[0131] The embodiments of the present invention disclosed above are merely illustrative of the invention. The embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for obtaining quantum efficiency, characterized in that, At least the following steps are included: Set at least two test exposure times, and acquire multiple frames of raw image data at each set wavelength and each test exposure time; Obtain the pixel value of each pixel in each frame of raw image data, and average the pixel values ​​of each pixel across multiple frames of raw image data to obtain the average frame image data; Define a test area, and average the pixel values ​​of all pixels in the test area in the average frame image data to obtain the average pixel value of the average frame. The ratio of the first difference between the average pixel values ​​of the average frames under two test exposure times to the second difference between the two test exposure times is used as the responsivity of the image sensor. as well as Based on the responsivity of the image sensor, the irradiance of the incident light, and the conversion gain of the image sensor, the actual photoelectric responsivity of the image sensor is obtained, and the ratio of the actual photoelectric responsivity to the theoretical responsivity is taken as the quantum efficiency.

2. The method for obtaining quantum efficiency according to claim 1, characterized in that, Setting the test exposure time includes the following steps: At the wavelength with the highest output optical power, the maximum test exposure time for the image to be in an unsaturated state was obtained; and At least two of the test exposure times are selected, and the test exposure times are less than the maximum test exposure time.

3. The method for obtaining quantum efficiency according to claim 1, characterized in that, Obtaining the irradiance of the incident light at each set wavelength includes the following steps: A photodetector is placed in the test optical path, and the photocurrent of the photodetector at the set wavelength is measured; and The irradiance of the incident light is obtained based on the effective light-receiving area and sensitivity of the photodetector.

4. The method for obtaining quantum efficiency according to claim 3, characterized in that, The irradiance of the incident light is obtained according to the following formula: Where E(λ) is the irradiance of the incident light, and λ is the wavelength of the incident light, I PD For photocurrent, S PD To maximize the effective light-receiving area, PD std (λ) represents the sensitivity.

5. The method for obtaining quantum efficiency according to claim 1, characterized in that, The conversion gain of the image sensor is obtained through the following steps: At multiple test exposure times within a preset wavelength, multiple frames of raw image data are acquired at each test exposure time. At each test exposure time, the pixel value of each pixel in each frame of raw image data is obtained, and the pixel values ​​of each pixel in multiple frames of raw image data are averaged to obtain the average frame image data; Obtain the pixel variance between the pixel value of each pixel in each frame of raw image data and the pixel value of each pixel in the average frame image data; Define a test area, average the pixel values ​​of all pixels in the test area in the average frame image data to obtain the average pixel value of the average frame, and obtain the median value of the pixel variance of all pixels in the test area. At each test exposure time, a point is determined with the average pixel value of the average frame on the horizontal axis and the median value of the pixel variance on the vertical axis. Linear fitting is performed on multiple points determined by the average pixel value of the average frame and the median value of the pixel variance at multiple test exposure times to obtain a linear slope. as well as The reciprocal of the linear slope is used as the conversion gain of the image sensor.

6. The method for obtaining quantum efficiency according to claim 1, characterized in that, The actual photoelectric responsivity is obtained using the following formula: Among them, R real ΔDN is the actual photoelectric responsivity of the image sensor, q is the electron charge constant, ΔDN is the difference in average pixel values ​​of the average frames under two test exposure times, ΔT is the difference in two test exposure times, ΔDN / ΔT is the responsivity of the image sensor, and k is the image sensor's responsivity. ADC For conversion gain, S pix E(λ) represents the effective photosensitive area of ​​a single pixel, and E(λ) represents the irradiance of the incident light.

7. The method for obtaining quantum efficiency according to claim 1, characterized in that, A set of test exposure times is selected, and there are two test exposure times in the set of test exposure times. Under the selected set of test exposure times, the quantum efficiency of the image sensor at each set wavelength is obtained, and a quantum efficiency versus wavelength curve is obtained.

8. The method for obtaining quantum efficiency according to claim 7, characterized in that, Multiple sets of test exposure times are obtained. Under each set of test exposure times, the quantum efficiency of the image sensor at each set wavelength is obtained. Multiple quantum efficiency versus wavelength curves corresponding to the multiple sets of test exposure times are obtained.

9. A system for achieving quantum efficiency, characterized in that, include: The raw image data acquisition module acquires multiple frames of raw image data at each set wavelength and each test exposure time; The average frame image data acquisition module acquires the pixel value of each pixel in each frame of raw image data, and averages the pixel values ​​of each pixel in multiple frames of raw image data to obtain the average frame image data. The average pixel value acquisition module of the average frame delineates a test area and averages the pixel values ​​of all pixels in the test area in the average frame image data to obtain the average pixel value of the average frame. The responsivity acquisition module uses the ratio of the first difference between the average pixel values ​​of the average frames under two test exposure times to the second difference between the two test exposure times as the responsivity of the image sensor. as well as The quantum efficiency acquisition module obtains the actual photoelectric responsivity of the image sensor based on the responsivity of the image sensor, the irradiance of the incident light, and the conversion gain of the image sensor, and uses the ratio of the actual photoelectric responsivity to the theoretical responsivity as the quantum efficiency.

10. An electronic device, characterized in that, The electronic device includes: A memory, wherein program instructions are stored; and The processor executes program instructions in the memory to implement the method for obtaining quantum efficiency as described in any one of claims 1 to 8.

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