Method and system for correcting non-uniformity of photosensitive element responsivity for multistage cold shield

Abstract

The application discloses a photosensitive element response rate non-uniformity correction method and system for a multi-stage cold shield, and relates to the technical field of data processing. The application can correct the response rate test result of a dewar inner detector containing a multi-stage cold shield and having an arbitrary shape of a window and a cold shield opening. A window surface is divided into grids, the effective solid angle of each window surface grid unit to a photosensitive element in a focal plane array infrared detector chip is calculated, a photosensitive element effective solid angle distribution matrix of the detector is generated, then, an F number distribution matrix of the photosensitive element in the entire focal plane array infrared detector chip is determined based on the photosensitive element effective solid angle distribution matrix of the detector, and the F number distribution matrix is used to correct a photosensitive element response rate matrix to realize the correction of focal plane response rate non-uniformity. The application has the advantages of simple algorithm implementation process, accurate calculation result, wide application range and the like.

Description

Technical Field

[0001] This invention relates to the field of data processing technology, and in particular to a method and system for correcting the non-uniformity of photosensitive element response rate in multi-level cold screens. Background Technology

[0002] When testing the responsivity of an infrared detector encapsulated within a Dewar flask, a cold screen mounted above the detector is needed to reduce background photon flux outside the optical field of view and suppress stray radiation interference with the signal. After testing, the F-number of the cold screen is used to calculate detector parameters such as the responsivity. However, the presence of holes and windows in the cold screen causes different photosensitive elements on the detector to receive different radiant fluxes. If the same F-number is used for calculations on different photosensitive elements, it will lead to significant errors. Therefore, the calculation must correct for the non-uniformity of photosensitive element response caused by different radiant fluxes; that is, different F-numbers are used for calculations on different photosensitive element test results. With the development of infrared detector component technology, the number of cold screen levels is gradually increasing, and the size and shape of the windows and openings of the Dewar components and cold screens are becoming increasingly diverse. This places higher demands on the photosensitive element responsivity non-uniformity correction algorithm.

[0003] Currently, a method for correcting the non-uniformity of response rate under the combined influence of window and cold screen has been disclosed (e.g., Chinese patent CN103335725B). Although this method can achieve non-uniformity correction of photosensitive element response rate, it is only applicable to the case of circular hole window and circular hole single-level cold screen, with a narrow range of application and an overly complex calculation method.

[0004] Therefore, there is an urgent need in this field to provide an algorithm for correcting the non-uniformity of photosensitive element response that can be used for multi-level cold screens, windows, and cold screen openings with arbitrary shapes, in order to overcome the shortcomings of existing methods. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for correcting the non-uniformity of photosensitive element response rate in multi-level cold screens. This method can be used for the non-uniformity correction process of photosensitive element response in multi-level cold screens, windows, and cold screen openings of arbitrary shapes, and can simplify the correction process while broadening the scope of application.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A method for correcting the non-uniformity of photosensitive element responsivity in a multi-level cold screen includes:

[0008] The model is constructed; the model includes a window, a multi-level cold screen structure, and an area array infrared detector chip;

[0009] The face of the window is divided into meshes to obtain window face mesh cells;

[0010] A three-dimensional coordinate system is established with the geometric center of the area array infrared detector chip model as the origin; in the three-dimensional coordinate system, the z-axis is perpendicular to the photosensitive surface of the area array infrared detector chip.

[0011] Based on the three-dimensional coordinate system, the solid angle of each window face grid unit to each photosensitive element in the array infrared detector chip is determined, and the effective solid angle of the window face to the photosensitive element is obtained to generate the effective solid angle distribution matrix of the detector photosensitive element.

[0012] The F-number distribution matrix of the photosensitive elements in the entire area array infrared detector chip is determined based on the effective solid angle distribution matrix of the photosensitive elements of the detector.

[0013] Based on the constructed model, the photosensitive element responsivity matrix was obtained through testing;

[0014] The photosensitive element responsivity matrix is ​​corrected using the F-number distribution matrix to obtain the corrected photosensitive element responsivity matrix.

[0015] Optionally, in the model, the vertical distance between the window and the area array infrared detector chip is:

[0016] In the formula, H is the vertical distance between the window and the area array infrared detector chip, h k Let be the vertical distance between the k-th level cold screen opening and the window, and n be the total number of levels of the cold screen structure, k = 1, 2, ..., n.

[0017] Optionally, the photosensitive element size of the area array infrared detector chip is M×N, where M is the number of columns, N is the number of rows, and the center distance between adjacent photosensitive elements is a.

[0018] Optionally, based on the three-dimensional coordinate system, the solid angle of each window face grid cell to each photosensitive element in the array infrared detector chip is determined to obtain the effective solid angle of the window face to the photosensitive element, so as to generate the effective solid angle distribution matrix of the detector photosensitive element, specifically including:

[0019] Determine the coordinates of the intersection point of the line connecting the center of the window surface grid unit and the center of the photosensitive element with each level of the cold screen surface;

[0020] Based on the coordinates, determine whether all intersection points fall within the corresponding level of cold screen opening range, and obtain the judgment result;

[0021] When the judgment result is yes, the solid angle of each window grid unit to each photosensitive element in the array infrared detector chip is determined as follows:

[0022] In the formula, ΔΩ ijLet be the effective solid angle of the window face to the photosensitive element, Δd be the grid side length, H be the vertical distance between the window and the area array infrared detector chip, i be the abscissa of the grid cell on the window face, x be the abscissa of the photosensitive element, j be the ordinate of the grid cell on the window face, and y be the ordinate of the photosensitive element.

[0023] When the judgment result is negative, the solid angle of each window grid unit to each photosensitive element in the array infrared detector chip is determined to be: ΔΩ. ij =0;

[0024] The effective solid angle of the window face to the photosensitive element is obtained by summing the solid angles of each window face grid unit to each photosensitive element in the array infrared detector chip.

[0025] The effective solid angle distribution matrix of the detector photosensitive element is generated based on the effective solid angle of the window facing the photosensitive element.

[0026] Optionally, the size of the effective solid angle distribution matrix of the detector photosensitive elements is the same as the size of the photosensitive elements in the area array infrared detector chip.

[0027] Optionally, the F-number distribution matrix is:

[0028]

[0029] In the formula, F MN Let Ω be the distribution matrix of the F-number. MN Let be the effective solid angle distribution matrix of the detector photosensitive element, and π be the value of pi.

[0030] Optionally, the corrected photosensitive element responsivity matrix is:

[0031]

[0032] In the formula, R MNadj R is the corrected photosensitive element responsivity matrix. MN To obtain the photosensitive element responsivity matrix from the test, F MN This is the F-number distribution matrix, where F is a fixed F value used when the photosensitive element responsivity matrix is ​​obtained through testing.

[0033] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0034] The present invention provides a method for correcting the non-uniformity of photosensitive element responsivity for multi-level cold screens. This method can correct the responsivity test results of Dewar's detectors containing multi-level cold screens with arbitrary shapes for the windows and cold screen openings. The method involves dividing the window surface into a grid, calculating the effective solid angle of each grid cell in the area array infrared detector chip to generate an effective solid angle distribution matrix for the detector photosensitive elements. Then, based on this effective solid angle distribution matrix, the F-number distribution matrix of the photosensitive elements in the entire area array infrared detector chip is determined. This F-number distribution matrix is ​​then used to correct the photosensitive element responsivity matrix, achieving correction of the non-uniformity of the responsivity on the focal plane. This method has advantages such as simple algorithm implementation, accurate calculation results, and wide applicability.

[0035] The present invention also provides a photosensitive element responsivity non-uniformity correction system for multi-level cold screens, applicable to the aforementioned photosensitive element responsivity non-uniformity correction method for multi-level cold screens; the system includes:

[0036] The model building module is used to build the model; the model includes a window, a multi-level cold screen structure, and an area array infrared detector chip.

[0037] The mesh generation module is used to divide the face of the window into mesh units to obtain window face mesh units;

[0038] The coordinate system construction module is used to establish a three-dimensional coordinate system with the geometric center of the area array infrared detector chip model as the origin; in the three-dimensional coordinate system, the z-axis is perpendicular to the photosensitive surface of the area array infrared detector chip;

[0039] The distribution matrix generation module is used to determine the solid angle of each window face grid unit to each photosensitive element in the array infrared detector chip based on the three-dimensional coordinate system, so as to obtain the effective solid angle of the window face to the photosensitive element and generate the effective solid angle distribution matrix of the detector photosensitive element.

[0040] The distribution matrix determination module is used to determine the F-number distribution matrix of the photosensitive elements in the entire area array infrared detector chip based on the effective solid angle distribution matrix of the photosensitive elements of the detector.

[0041] The response rate matrix testing module is used to test and obtain the photosensitive element response rate matrix based on the constructed model.

[0042] The response rate matrix correction module is used to correct the photosensitive element response rate matrix using the F-number distribution matrix to obtain the corrected photosensitive element response rate matrix.

[0043] A computer-readable storage medium for storing a computer program; the computer program is used to implement the above-described method for correcting the non-uniformity of photosensitive element responsivity in a multi-level cold screen.

[0044] Since the technical effects achieved by the two implementation structures provided by the present invention are the same as those achieved by the method for correcting the non-uniformity of photosensitive element response rate of multi-level cold screens provided by the present invention, they will not be described in detail here. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in 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.

[0046] Figure 1 A flowchart of the photosensitive element non-uniformity correction method for multi-level cold screens provided by the present invention;

[0047] Figure 2 A schematic diagram of the window and multi-level cold screen structure model provided by the present invention;

[0048] Figure 3 The response rate distribution diagram of the center row of the detector before calibration provided by the present invention;

[0049] Figure 4 The response rate distribution diagram of the center row of the calibrated detector provided by this invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] The purpose of this invention is to provide a method and system for correcting the non-uniformity of photosensitive element response rate in multi-level cold screens. This method can be used for the non-uniformity correction process of photosensitive element response in multi-level cold screens, windows, and cold screen openings of arbitrary shapes, and can simplify the correction process while broadening the scope of application.

[0052] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] like Figure 1 As shown, the method for correcting the non-uniformity of photosensitive element responsivity for multi-level cold screens provided by the present invention includes:

[0054] Step 100: Build the model. For example... Figure 2As shown, the constructed model includes window 1, a multi-level cold screen structure, and an area array infrared detector chip 6. The multi-level cold screen structure refers to the multiple openings that limit light flux between the window and the infrared detector chip. The number of such structures determines the number of cold screen levels. Assuming there are (n-1) levels in total, the cold screen closest to the window is level 1, the perpendicular distance between the opening of level 1 and the window is h1, the perpendicular distance between the opening of level 2 and the opening of level 1 is h2, ..., the perpendicular distance between the opening of level (n-1) and the opening of level (n-2) is h... n-1 The vertical distance between the (n-1)th level cold screen aperture and the area array infrared detector chip is h. n The vertical distance between the window and the area array infrared detector chip is... In the formula, H is the vertical distance between the window and the area array infrared detector chip, h k Let be the vertical distance between the k-th level cold screen opening and the window, and n be the total number of levels of the cold screen structure, k = 1, 2, ..., n.

[0055] Among them, such as Figure 2 As shown, the first level of cold screen is labeled as 2, the second level of cold screen is labeled as 3, and so on, with the qth level of cold screen labeled as 4 and the (n-1)th level of cold screen labeled as 5.

[0056] The photosensitive element size of the area array infrared detector chip is M×N, where M is the number of columns, N is the number of rows, and the center distance between adjacent photosensitive elements is a.

[0057] Step 101: Mesh the window face to obtain window face mesh cells. Assume each mesh edge length is Δd.

[0058] Step 102: Establish a three-dimensional coordinate system with the geometric center of the area array infrared detector chip model as the origin. In the three-dimensional coordinate system, the z-axis is perpendicular to the photosensitive surface of the area array infrared detector chip. Based on this constructed three-dimensional coordinate system, the window surface mesh element divided in the above steps is denoted as w. ij Its coordinates are (i,j,H), and the photosensitive element of the area array infrared detector chip is denoted as s. xy Its coordinates are (x, y, 0).

[0059] Step 103: Determine the solid angle of each window face grid cell to each photosensitive element in the array infrared detector chip based on the three-dimensional coordinate system, and obtain the effective solid angle of the window face to the photosensitive element to generate the effective solid angle distribution matrix of the detector photosensitive element.

[0060] The specific implementation process for this step can be as follows:

[0061] Step 1031: Determine the coordinates of the intersection point between the center line connecting the window surface mesh element and the photosensitive element and the cold screen surface at each level. Specifically, in the three-dimensional coordinate system, the calculated window surface mesh element w... ij and photosensitive element s xy The coordinates of the intersection points of the center line and each cold screen surface are as follows:

[0062] Coordinates of the intersection point with the first-level cold screen surface:

[0063] Coordinates of the intersection point with the second-level cold screen surface:

[0064] ...

[0065] The coordinates of the intersection point with the q-th level cold screen surface:

[0066] ...

[0067] The coordinates of the intersection point with the (n-1)th level cold screen surface:

[0068] Step 1032: Determine whether all intersection points fall within the corresponding level of the cold screen opening range based on the coordinates, and obtain the determination result. That is, determine whether all n-1 intersection points fall within the corresponding level of the cold screen opening range.

[0069] Step 1033: When the judgment result is yes, determine the solid angle of each window grid cell to each photosensitive element in the array infrared detector chip as follows:

[0070] In the formula, ΔΩ ij Let be the effective solid angle of the window face to the photosensitive element, Δd be the grid side length, H be the vertical distance between the window and the area array infrared detector chip, i be the abscissa of the grid cell on the window face, x be the abscissa of the photosensitive element, j be the ordinate of the grid cell on the window face, and y be the ordinate of the photosensitive element.

[0071] Step 1034: When the judgment result is negative, determine the solid angle ΔΩ of each window grid cell to each photosensitive element in the array infrared detector chip. ij =0.

[0072] Step 1035: Repeat steps 1033 and 1034. After traversing all the grids of the window face, sum the solid angles of each grid cell of the window face to each photosensitive element in the array infrared detector chip to obtain the effective solid angle of the window face to the photosensitive element. This effective solid angle is denoted as ΔΩ. xy .

[0073] Step 1036: Repeat steps 1033 to 1035, traversing all photosensitive elements, to obtain the effective solid angle ΔΩ of the window facing each photosensitive element. xy That is, the effective solid angle distribution matrix Ω of the entire detector photosensitive element is obtained. MN Matrix Ω MN The element is the effective solid angle ΔΩ of the window facing a single photosensitive element. xy The size of the matrix is ​​consistent with the size of the photosensitive elements of the area array infrared detector chip, which is M×N.

[0074] Step 104: Determine the F-number distribution matrix of the photosensitive elements in the entire area array infrared detector chip based on the effective solid angle distribution matrix of the detector photosensitive elements. The F-number distribution matrix is ​​as follows:

[0075]

[0076] In the formula, F MN Let F be the distribution matrix of the F-number, and π be the value of pi.

[0077] It should be noted that this step follows array operation rules, not matrix operation rules.

[0078] Step 105: Based on the constructed model, the photoresponse matrix of the photosensitive element is obtained through testing. The obtained photoresponse matrix of the photosensitive element is denoted as R. MN .

[0079] Step 106: Correct the photosensitive element responsivity matrix using the F-number distribution matrix to obtain the corrected photosensitive element responsivity matrix. The corrected photosensitive element responsivity matrix is ​​as follows:

[0080]

[0081] In the formula, R MNadj R is the corrected photoresponsivity matrix of the photosensitive element. MN For the photoresponsivity matrix obtained from the test, F MN This is the F-number distribution matrix, where F is a fixed F value used when the photosensitive element responsivity matrix is ​​obtained through testing.

[0082] Similarly, the calculation in this step follows array operation rules, not matrix operation rules.

[0083] Based on the above description, the present invention divides the window surface into grids. When calculating the effective solid angle of each grid relative to the photosensitive element, it filters out the blocked light paths by judging whether the light path can pass through each level of cold screen aperture. Finally, it obtains the effective solid angle of the entire window surface relative to the photosensitive element by summing the results. The above process is repeated for all photosensitive elements to obtain the effective solid angle distribution matrix of the photosensitive surface, thereby realizing the correction of the non-uniformity of the focus plane response rate.

[0084] Therefore, compared with the prior art, the advantages of the present invention are as follows:

[0085] 1) The algorithm implementation process is simple: the entire algorithm implementation process only involves simple arithmetic operations and loop and judgment structures.

[0086] 2) Accurate Calculation Results: Because this method involves calculating solid angles, which involves complex integral calculations and rarely has analytical solutions, numerical solutions are necessary. The smaller the Δd set during the calculation process, the more accurate the results will be.

[0087] 3) Wide range of applications: There are no restrictions on the number of levels and shape and size of the cold screen in the implementation of this invention.

[0088] Furthermore, the present invention also provides a photosensitive element responsivity non-uniformity correction system for multi-level cold screens, applicable to the aforementioned photosensitive element responsivity non-uniformity correction method for multi-level cold screens. The system includes:

[0089] The model building module is used to construct the model. The model includes windows, a multi-level cold screen structure, and an area array infrared detector chip.

[0090] The mesh generation module is used to divide the face of a window into mesh units.

[0091] The coordinate system construction module is used to establish a three-dimensional coordinate system with the geometric center of the area array infrared detector chip model as the origin. In the three-dimensional coordinate system, the z-axis is perpendicular to the photosensitive surface of the area array infrared detector chip.

[0092] The distribution matrix generation module is used to determine the solid angle of each window face grid cell to each photosensitive element in the array infrared detector chip based on the three-dimensional coordinate system, so as to obtain the effective solid angle of the window face to the photosensitive element and generate the effective solid angle distribution matrix of the detector photosensitive element.

[0093] The distribution matrix determination module is used to determine the F-number distribution matrix of the photosensitive elements in the entire area array infrared detector chip based on the effective solid angle distribution matrix of the detector photosensitive elements.

[0094] The response rate matrix testing module is used to test and obtain the photosensitive element response rate matrix based on the constructed model.

[0095] The response rate matrix correction module is used to correct the photosensitive element response rate matrix using the F-number distribution matrix to obtain the corrected photosensitive element response rate matrix.

[0096] Furthermore, the program is written according to steps 100 to 106 of the above-described method for correcting the non-uniformity of photosensitive element responsivity in multi-level cold screens. In actual use, the following inputs are required: the shape and size of the window and each level of cold screens; the vertical distance between the window and the first-level cold screen; the vertical distance between each level of cold screens; the vertical distance between the last-level cold screen and the area array infrared detector chip; the grid side length; the photosensitive element size and center-to-center distance of the area array infrared detector chip; the photosensitive element responsivity matrix before correction; and the fixed F-number used to calculate this matrix. If the actual number of cold screen levels p is less than the number of cold screen levels n-1 set in the program, it is only necessary to set the shape and size of the cold screens from p+1 to n-1 levels in the program to be consistent with the area array infrared detector chip, and to set the distance between the cold screens from p+1 to n-1 levels in the program and the next level of cold screen to be 0. The program outputs the corrected photosensitive element F-number distribution matrix and the corrected photosensitive element responsivity matrix.

[0097] Based on this, when the aforementioned method for correcting the non-uniformity of photosensitive element responsivity in multi-level cold screens is implemented as a computer program through software functional units and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0098] The advantages of the photosensitive element responsivity non-uniformity correction method for multi-level cold screens provided by the present invention are further detailed below using an embodiment:

[0099] This embodiment corrects for the non-uniformity of the responsivity of an infrared focal plane detector with a scale of 512×512 and a center-to-center distance of 30μm. The Dewar structure contains three levels of cold screens. The geometric parameters of the window and the cold screens are as follows: the window is circular with a diameter of 25000μm; the perpendicular distance h1 between the window and the opening of the first-level cold screen is 5500μm; the opening of the first-level cold screen is circular with a diameter of 11000μm; the perpendicular distance h2 between the opening of the first-level cold screen and the opening of the second-level cold screen is 7000μm; the opening of the second-level cold screen is square with a side length of 13000μm; the perpendicular distance h3 between the opening of the second-level cold screen and the opening of the third-level cold screen is 7000μm; the opening of the third-level cold screen is square with a side length of 18000μm; and the perpendicular distance h4 between the opening of the third-level cold screen and the photosensitive surface is 2000μm. Input the above parameters, the photosensitive element responsivity matrix before correction, and the fixed F-number (e.g., 1.4) used to calculate the matrix into the computer program provided by this invention. The result of correcting the non-uniformity of the responsivity is shown in the appendix. Figure 3 and Figure 4 As shown, the uniformity of the response rate is significantly improved after correction compared to before correction, and the overall non-uniformity of the detector array response is reduced from 18% before correction to 4.1% after correction. The non-uniformity after correction is mainly caused by the series resistance of different photosensitive elements in the detector and is unrelated to the effects of the cold screen and window.

[0100] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0101] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for correcting the non-uniformity of photosensitive element responsivity in a multi-level cold screen, characterized in that, include: Build a model; The model includes a window, a multi-level cold screen structure, and an array infrared detector chip. The face of the window is divided into meshes to obtain window face mesh cells; A three-dimensional coordinate system is established with the geometric center of the area array infrared detector chip model as the origin; in the three-dimensional coordinate system, the z-axis is perpendicular to the photosensitive surface of the area array infrared detector chip. Based on the three-dimensional coordinate system, the solid angle of each window face grid unit to each photosensitive element in the array infrared detector chip is determined, and the effective solid angle of the window face to the photosensitive element is obtained to generate the effective solid angle distribution matrix of the detector photosensitive element. The F-number distribution matrix of the photosensitive elements in the entire area array infrared detector chip is determined based on the effective solid angle distribution matrix of the photosensitive elements; the F-number distribution matrix is: ； In the formula, The F-number distribution matrix, The effective solid angle distribution matrix of the detector photosensitive elements. Pi; Based on the constructed model, the photosensitive element responsivity matrix was obtained through testing; The photosensitive element responsivity matrix is ​​corrected using the F-number distribution matrix to obtain the corrected photosensitive element responsivity matrix; the corrected photosensitive element responsivity matrix is: ； In the formula, This is the corrected photosensitive element responsivity matrix. The photoresponse matrix obtained from the test, The F-number distribution matrix, The fixed F value used when testing and obtaining the photosensitive element responsivity matrix; Specifically, based on the three-dimensional coordinate system, the solid angle of each window face grid cell to each photosensitive element in the array infrared detector chip is determined, thereby obtaining the effective solid angle of the window face to the photosensitive element, and generating the effective solid angle distribution matrix of the detector photosensitive elements, including: Determine the coordinates of the intersection point of the line connecting the center of the window surface grid unit and the center of the photosensitive element with each level of the cold screen surface; Based on the coordinates, determine whether all intersection points fall within the corresponding level of cold screen opening range, and obtain the judgment result; When the judgment result is yes, the solid angle of each window grid unit to each photosensitive element in the array infrared detector chip is determined as follows: ; In the formula, The effective solid angle of the window facing the photosensitive element. Let be the grid side length. This is the vertical distance between the window and the area array infrared detector chip. The x-coordinate of the window face grid cell. The x-coordinate of the photosensitive element is denoted as . The vertical coordinate of the window surface grid cell. The vertical coordinate of the photosensitive element; When the judgment result is negative, the solid angle of each window grid unit to each photosensitive element in the array infrared detector chip is determined as follows: ; The effective solid angle of the window face to the photosensitive element is obtained by summing the solid angles of each window face grid unit to each photosensitive element in the array infrared detector chip. The effective solid angle distribution matrix of the detector photosensitive element is generated based on the effective solid angle of the window facing the photosensitive element.

2. The method for correcting the non-uniformity of photosensitive element responsivity for multi-level cold screens according to claim 1, characterized in that, In the model, the vertical distance between the window and the area array infrared detector chip is: ; In the formula, This is the vertical distance between the window and the area array infrared detector chip. n -1 represents the total number of levels in the cold screen structure. k =1,2,..., n The vertical distance between the first-level cold screen opening and the window is h 1. The vertical distance between the second-level cold screen opening and the first-level cold screen opening is... h 2,…,No. n -1 level cold screen opening and the first n The vertical distance of the -2 level cold screen opening is h n-1 , No. n The vertical distance between the -1 level cold screen aperture and the area array infrared detector chip is h n 。 3. The method for correcting the non-uniformity of photosensitive element responsivity for multi-level cold screens according to claim 1, characterized in that, The photosensitive element size of the area array infrared detector chip is M×N, where M is the number of columns, N is the number of rows, and the center distance between adjacent photosensitive elements is a.

4. The method for correcting the non-uniformity of photosensitive element responsivity for multi-level cold screens according to claim 1, characterized in that, The size of the effective solid angle distribution matrix of the detector photosensitive elements is the same as the size of the photosensitive elements in the area array infrared detector chip.

5. A photosensitive element responsivity non-uniformity correction system for multi-level cold screens, characterized in that, The system is applied to the photosensitive element responsivity nonuniformity correction method for multi-level cold screens as described in any one of claims 1-4; the system comprises: The model building module is used to build the model; the model includes a window, a multi-level cold screen structure, and an area array infrared detector chip. The mesh generation module is used to divide the face of the window into mesh units to obtain window face mesh units; The coordinate system construction module is used to establish a three-dimensional coordinate system with the geometric center of the area array infrared detector chip model as the origin; in the three-dimensional coordinate system, the z-axis is perpendicular to the photosensitive surface of the area array infrared detector chip; The distribution matrix generation module is used to determine the solid angle of each window face grid unit to each photosensitive element in the array infrared detector chip based on the three-dimensional coordinate system, so as to obtain the effective solid angle of the window face to the photosensitive element and generate the effective solid angle distribution matrix of the detector photosensitive element. The distribution matrix determination module is used to determine the F-number distribution matrix of the photosensitive elements in the entire area array infrared detector chip based on the effective solid angle distribution matrix of the photosensitive elements of the detector. The response rate matrix testing module is used to test and obtain the photosensitive element response rate matrix based on the constructed model. The response rate matrix correction module is used to correct the photosensitive element response rate matrix using the F-number distribution matrix to obtain the corrected photosensitive element response rate matrix.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program; the computer program is used to implement the photosensitive element responsivity non-uniformity correction method for multi-level cold screens as described in any one of claims 1-4.

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