Optical axis center correction method for optoelectronic pod imaging module

Abstract

The application discloses a kind of optical axis center correction methods of optoelectronic pod imaging module, comprising: in imaging module, select an imaging module as standard module, and the optical axis center of standard module is corrected by hardware;Each imaging module in imaging module is respectively imaged to calibration chart, and the imaging image of each imaging module is obtained;According to the imaging image of each imaging module, its image parameter is calculated;According to the image parameter of standard module and the image parameter of the rest imaging module, the relative parameter of the rest imaging module is calculated respectively;According to the relative parameter of the rest imaging module, the optical axis center of the rest imaging module is calibrated respectively.In the present application, correction process is simple, correction equipment cost is low, efficiency is high, and it can be mass-produced quickly, with wide application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of optoelectronic pods, and particularly relates to a method for correcting the optical axis center of an imaging module of an optoelectronic pod. BACKGROUND

[0002] An optoelectronic pod is a sensor system that is very important for a modern aircraft (such as a drone, a military aircraft, a police helicopter, etc.), and is internally provided with multiple imaging modules, like the "eyes" of the aircraft, so that it can "see" clearly and "see" far in various environments and obtain target information. Since the different imaging modules in the optoelectronic pod have their own physical installation positions, there are inevitably slight deviations in the mechanical axes of the imaging modules during processing and assembly. At the same time, environmental factors such as temperature changes, vibrations, and impacts can also cause these deviations to change. Therefore, it is necessary to correct the "line of sight" of all the imaging modules and the "pointing" of the laser beams in the optoelectronic pod to be strictly parallel to each other and aligned with the same absolute correct reference point, so as to ensure the measurement accuracy of the optoelectronic pod. In addition, one of the core functions of a modern optoelectronic pod is image fusion (for example, fusing a high-definition visible light image and an infrared thermal imaging picture together). To achieve perfect fusion, it is also necessary to ensure that each pixel point on the visible light imaging module looks at the same point on the ground as the corresponding pixel point on the infrared thermal imager detector. In the prior art, each imaging module is calibrated by a hardware alignment method, which requires an expensive automatic calibration mechanism, has a high calibration cost, and also needs manual precise mechanical alignment, so the calibration efficiency is low. SUMMARY

[0003] In view of the above problems in the prior art, the technical problem to be solved by the present application is to provide a method for correcting the optical axis center of an imaging module of an optoelectronic pod.

[0004] To solve the above technical problems, the present application provides the following technical solutions:

[0005] A method for correcting the optical axis center of an imaging module of an optoelectronic pod, the optoelectronic pod being provided with an imaging module group, comprising the following steps:

[0006] S100, selecting an imaging module as a standard module in the imaging module group, and performing hardware correction on the optical axis center of the standard module;

[0007] S200, imaging each imaging module in the imaging module group on a correction chart to obtain an imaging image of each imaging module;

[0008] S300, calculating an image parameter of each imaging module according to the imaging image of each imaging module; the image parameter of each imaging module includes a center point coordinate, a pixel size, and a rotation parameter matrix of the imaging image of each imaging module;

[0009] S400, calculate the relative parameters of the rest of the imaging modules according to the image parameters of the standard module and the image parameters of the rest of the imaging modules respectively; the relative parameters include pixel translation parameters, focal length magnification parameters and pixel transfer parameters; the pixel translation parameters of each of the rest of the imaging modules are calculated according to the center point coordinates of the image parameters thereof and the center point coordinates in the image parameters of the standard module; the focal length magnification parameters of each of the rest of the imaging modules are calculated according to the pixel sizes of the image parameters thereof and the pixel sizes in the image parameters of the standard module; the pixel transfer parameters of each of the rest of the imaging modules are calculated according to the rotation parameter matrices of the image parameters thereof and the rotation parameter matrices in the image parameters of the standard module;

[0010] S500, calibrate the optical axis centers of the rest of the imaging modules according to the relative parameters of the rest of the imaging modules respectively; the calibration method is that after imaging is performed on each imaging module, first, the coordinates of the pixel points in the imaging images of the rest of the imaging modules are translated according to the pixel translation parameters and the focal length magnification when imaging, then the translated pixel point coordinates are scaled according to the focal length magnification parameters, and finally the pixel point coordinates are sequentially normalized, rotated and re-projected according to the pixel transfer parameters.

[0011] Further, the method for performing hardware correction on the optical axis center of the standard module is that a rectangular area is set as an imaging area on the correction chart, and the lens center of the standard module is aligned with the center point of the rectangular area.

[0012] Further, the imaging module includes a zoom module, and the zoom module is selected as the standard module; in the S200 step, each imaging module respectively images the correction chart at the 1X focal length of the zoom module.

[0013] Further, the imaging module further includes a wide-angle module;

[0014] The rectangular area of the correction chart is provided with a first corner point group, the first corner point group includes four first black and white corner point patterns, the center points of the four first black and white corner point patterns are respectively located on two diagonal lines of the rectangular area, the center points of the two first black and white corner point patterns on each of the diagonal lines are symmetrically arranged on both sides of the center point of the rectangular area, and the distances between the center points of the four first black and white corner point patterns and the center point of the rectangular area are all equal;

[0015] The image parameters of the zoom module include a first center point coordinate, a first pixel size, and a first rotation matrix; the first center point coordinate is a center point coordinate of a rectangular region calculated according to center point coordinates of four first black-and-white corner point patterns in an imaging image of the zoom module; the first pixel size includes a first pixel width and / or a first pixel height, the first pixel width is a distance between two feature points selected in the same horizontal direction in the imaging image of the zoom module, and the first pixel height is a distance between two feature points selected in the same vertical direction in the imaging image of the zoom module; and the first rotation matrix is a rotation parameter matrix calculated according to the imaging image of the zoom module.

[0016] The image parameters of the wide-angle module include a second center point coordinate, a second pixel size, and a second rotation matrix; the second center point coordinate is a center point coordinate of a correction chart calculated according to center point coordinates of the four first black-and-white corner point patterns in the imaging image of the wide-angle module; the second pixel size includes a second pixel width and / or a second pixel height, the second pixel width is a distance between two feature points corresponding to the first pixel width in the imaging image of the wide-angle module, and the second pixel height is a distance between two feature points corresponding to the first pixel height in the imaging image of the wide-angle module; and the second rotation matrix is a rotation parameter matrix calculated according to the imaging image of the wide-angle module.

[0017] The relative parameters of the wide-angle module include a first pixel translation parameter, a first focal length magnification parameter, and a first pixel transfer parameter; the first pixel translation parameter is calculated according to the first center point coordinate and the second center point coordinate; the first focal length magnification parameter is calculated according to the first pixel size and the second pixel size; and the first pixel transfer parameter is calculated according to the first rotation matrix and the second rotation matrix.

[0018] Further, the four first black-and-white corner point patterns of the first corner point group are located at four corner regions of the rectangular region, respectively.

[0019] Further, the first center point coordinate is an average value of center point coordinates of the four first black-and-white corner point patterns in the imaging image of the zoom module, the second center point coordinate is an average value of center point coordinates of the four first black-and-white corner point patterns in the imaging image of the wide-angle module, the first pixel translation parameter is a difference between the second center point coordinate and the first center point coordinate, the first focal length magnification parameter is a ratio of the second pixel size to the first pixel size, and the first pixel transfer parameter is obtained by multiplying a transposed matrix of the second rotation matrix with the first rotation matrix.

[0020] Further, the imaging module further comprises a thermal imaging module, and a second corner point group is arranged in the rectangular region of the correction board, the second corner point group comprises four second black and white corner point patterns, and the center points of the four second black and white corner point patterns are respectively located on two diagonal lines of the rectangular region, the center points of the two second black and white corner point patterns on each diagonal line are symmetrically arranged on both sides of the center point of the rectangular region, and the distances from the center points of the four second black and white corner point patterns to the center point of the rectangular region are equal; a constant temperature metal rod is vertically arranged in the middle of each second black and white corner point pattern, and the center point of the second black and white corner point pattern is located on the axis of the constant temperature metal rod;

[0021] The image parameters of the zoom module include third center point coordinates, third pixel sizes and a third rotation matrix; the third center point coordinates are center point coordinates of the rectangular region calculated according to the center point coordinates of the four second black and white corner point patterns in the imaging image of the zoom module; the third pixel sizes include a third pixel width and / or a third pixel height, the third pixel width is the distance between the center points of the two second black and white corner point patterns symmetrically arranged in the horizontal direction in the imaging image of the zoom module, and the third pixel height is the distance between the center points of the two second black and white corner point patterns symmetrically arranged in the vertical direction in the imaging image of the zoom module; and the third rotation matrix is a rotation parameter matrix calculated according to the center point coordinates of the four second black and white corner point patterns in the imaging image of the zoom module;

[0022] The image parameters of the thermal imaging module include fourth center point coordinates, fourth pixel sizes and a fourth rotation matrix; the fourth center point coordinates are center point coordinates of the correction board calculated according to the center point coordinates of the four constant temperature metal rods in the imaging image of the thermal imaging module; the fourth pixel sizes include a fourth pixel width and / or a fourth pixel height, the fourth pixel width is the distance between the center points of the two constant temperature metal rods symmetrically arranged in the horizontal direction in the imaging image of the thermal imaging module, and the fourth pixel height is the distance between the center points of the two constant temperature metal rods symmetrically arranged in the vertical direction in the imaging image of the thermal imaging module; and the fourth rotation matrix is a rotation parameter matrix calculated according to the center point coordinates of the four constant temperature metal rods in the imaging image of the thermal imaging module;

[0023] The relative parameters of the thermal imaging module include a second pixel translation parameter, a second focal length magnification parameter and a second pixel transfer parameter; the second pixel translation parameter is calculated according to the third center point coordinates and the fourth center point coordinates; the second focal length magnification parameter is calculated according to the third pixel sizes and the fourth pixel sizes; and the second pixel transfer parameter is calculated according to the third rotation matrix and the fourth rotation matrix.

[0024] Further, the third center point coordinate is obtained by averaging the center point coordinates of the four second black and white corner point patterns in the imaging image of the zoom module, and the fourth center point coordinate is obtained by averaging the center point coordinates of the four constant temperature metal rods in the imaging image of the thermal imaging module; the second pixel translation parameter is the difference between the fourth center point coordinate and the third center point coordinate; the second focal length ratio parameter is the ratio of the fourth pixel size to the third pixel size; and the second pixel transfer parameter is obtained by multiplying the fourth rotation matrix and the transpose matrix of the third rotation matrix.

[0025] Further, the photoelectric pod further comprises an auxiliary imaging module, the auxiliary imaging module comprises a laser ranging module, and the middle part of the correction board is provided with a laser observation card; the image parameters of the standard module include a fifth center coordinate, and the fifth center coordinate is the center point coordinate of the imaging image of the standard module; in the S200 step, the laser ranging module also emits laser to the laser observation card, in the S300 step, the laser spot center coordinate is taken as the image parameter of the laser ranging module, and the laser spot center coordinate is the center point coordinate of the laser spot pattern formed by the laser emitted by the laser ranging module on the laser observation card; the relative parameters of the laser ranging module include a third pixel translation parameter, and the third pixel translation parameter is the difference between the laser spot center coordinate and the fifth center coordinate; in the S500 step, the optical axis center of the laser ranging module is also calibrated according to the relative parameters of the laser ranging module.

[0026] Further, the method for calculating the fifth center coordinate is as follows: half of the width of the imaging image of the standard module is taken as the x-axis coordinate of the fifth center coordinate; and half of the height of the imaging image of the standard module is taken as the y-axis coordinate of the fifth center coordinate.

[0027] The method for calculating the laser spot center coordinate is as follows: the correction board is continuously imaged by using the standard module to obtain a plurality of images, and the first image of the continuous imaging is subtracted from the remaining images in turn to obtain a plurality of difference images, the maximum value of the difference images is found out, the laser spot pattern is found out from the difference image, and the center point coordinate of the laser spot pattern is calculated.

[0028] In the present application, the optical axis deviation is corrected by software and image processing algorithm, and the correction process can be completed only by simple optical calibration board and general test software, without the need of expensive automatic calibration mechanism, so that the labor cost of precise mechanical alignment can be saved. In addition, the correction process is simple and efficient, and can be quickly mass-produced, which is suitable for multiple machine bodies or deployment of a large number of pods at one time. The optical axis deviation can be quickly adjusted on site, without the need of returning to the factory for fine repair, and has a wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0030] Figure 1 Flow chart of the optical axis center correction method of the optical-electric pod imaging module according to an embodiment of the present application.

[0031] Figure 2 Structure diagram of the correction board.

[0032] Figure 3 Structure diagram of the laser observation card.

[0033] The description of the drawings is as follows:

[0034] Correction board-1; first black and white corner point pattern-2; second black and white corner point pattern-3; constant temperature metal rod-4; laser observation card-5; zoom module pattern-6; laser ranging module pattern-7; wide-angle module pattern-8; constant temperature metal rod pattern-9. DETAILED DESCRIPTION

[0035] The embodiments of the present application will be described in detail below with specific reference to the accompanying drawings. The following examples are provided to illustrate the basic concepts of the present application, and the following examples and features in the examples can be combined with each other without conflict.

[0036] Please refer to Figure 1 , Figure 1 Flow chart of the optical axis center correction method of the optical-electric pod imaging module according to an embodiment of the present application. The optical-electric pod is provided with an imaging module, and the imaging module includes a plurality of imaging modules. The optical axis center correction method of the optical-electric pod imaging module according to the embodiment includes the following steps:

[0037] S100, select an imaging module as a standard module in the imaging module, and perform hardware correction on the optical axis center of the standard module. The method for performing hardware correction on the optical axis center of the standard module is to set a rectangular area as an imaging area on the correction board 1, and align the lens center of the standard module with the center point of the rectangular area. In the embodiment, the correction board 1 is directly used in a rectangular shape, so that the outer contour of the correction board 1 forms a rectangular area, and it is not necessary to separately divide a rectangular area. Of course, other shapes of the correction board 1 can also be used, and a rectangular area can be marked on the correction board 1.

[0038] In the embodiment, the optoelectronic pod adopts a four-optical pod, and in addition to the imaging module, an auxiliary imaging module is further included, which is a module for imaging assistance. The imaging modules in the imaging module include a zoom module, a wide-angle module, and a thermal imaging module, and the auxiliary imaging module includes a laser ranging module. In the embodiment, the zoom module is selected as the standard module, and the correction method is described by taking the structure of the four-optical pod as an example. Of course, the optoelectronic pod does not necessarily include the above four modules, but can only include part of the above four modules, or include more modules.

[0039] S200, each imaging module (i.e., zoom module, wide-angle module, and thermal imaging module) in the imaging module is respectively imaged on the correction chart 1 to obtain an imaging image of each imaging module; at the same time, the laser ranging module emits laser to the laser observation card. Please refer to Figure 2 In the embodiment, the rectangular area of the correction chart 1 is provided with a first corner point group, a second corner point group, a constant temperature metal rod 4, and a laser observation card 5. Each imaging module can simultaneously image the correction chart 1 at the 1X focal length of the zoom module, so that the coefficient of the focal length can be ignored to facilitate the subsequent calculation process. The core function of the laser observation card 5 is to convert the invisible infrared laser spot to the visible light spot that can be clearly seen by the naked eye, so that the zoom module can image the laser spot pattern. Since the laser ranging module needs to collect multiple images to find the laser spot pattern, the zoom module needs to image multiple times.

[0040] The first corner point group includes four first black and white corner point patterns 2, and the center points of the four first black and white corner point patterns 2 are respectively located on two diagonal lines (i.e. Figure 2 two inclined dashed lines) of the rectangular area, and the first black and white corner point pattern 2 is a pattern composed of two black rectangular blocks and two white rectangular blocks in a checkerboard form, and the common vertex of the two black rectangular blocks and the two white rectangular blocks is the corner point of the first black and white corner point pattern 2.

[0041] The center points of the two first black and white corner point patterns 2 on each diagonal line are symmetrically arranged on both sides of the center point of the rectangular area, and the distances from the center points of the four first black and white corner point patterns 2 to the center point of the rectangular area are equal. The first corner point group is used for optical axis center correction of the wide-angle module, so the four first black and white corner point patterns 2 of the first corner point group can be respectively located in the four corner regions of the rectangular area, and of course, the four first black and white corner point patterns 2 also need to be within the imaging range of the zoom module.

[0042] The second corner dot group includes four second black and white corner dot patterns 3. The structure of the second black and white corner dot pattern 3 is similar to that of the first black and white corner dot pattern 2. It is also a pattern composed of two black rectangular blocks and two white rectangular blocks in a checkerboard pattern. However, the size of the second black and white corner dot pattern 3 is generally smaller than that of the first black and white corner dot pattern 2.

[0043] The center points of the four second black and white corner dot patterns 3 are respectively located on the two diagonals of the rectangular area. The center points of the two second black and white corner dot patterns 3 on each diagonal are symmetrically arranged on both sides of the center point of the rectangular area, and the distances between the center points of the four second black and white corner dot patterns 3 and the center point of the rectangular area are all equal. A thermostatic metal rod 4 is vertically inserted through the middle part of each second black and white corner dot pattern 3, and the center point of the second black and white corner dot pattern 3 is located on the axis of the thermostatic metal rod 4. The second corner dot group and the four thermostatic metal rods 4 are used for optical axis center correction of the thermal imaging module. The four second black and white corner dot patterns 3 of the second corner dot group are generally located inside the first corner dot group.

[0044] Please see Figure 3 For ease of observation, a photoelectric pod pattern can be formed on the laser observation card 5. The photoelectric pod pattern can include a zoom module graphic 6, a laser ranging module graphic 7, a wide-angle module graphic 8, and a constant-temperature metal rod graphic 9 formed at a 1:1 scale according to the relative positions of the shapes of each imaging module. The center of the zoom module graphic 6 in the photoelectric pod pattern is aligned with the center of the rectangular area.

[0045] S300. Calculate the image parameters of each imaging module based on its imaging images. The image parameters of each imaging module include the center point coordinates, pixel size, and rotation parameter matrix of its imaging image. The center coordinates of the laser spot are used as the image parameters of the laser ranging module. Specifically, to perform optical axis center correction on the wide-angle module, the image parameters of the zoom module may include the first center point coordinates, the first pixel size, and the first rotation matrix. The first center point coordinates are the center point coordinates of the rectangular area calculated based on the center point coordinates of the four first black and white corner pattern 2 in the imaging image of the zoom module. For example, the first center point coordinates can be obtained by averaging the center point coordinates of the four first black and white corner pattern 2 in the imaging image of the zoom module. Assume that the center point coordinates of the four first black and white corner pattern 2 in the imaging image of the zoom module are (cx... 00 ,cy 00 (cx) 01 ,cy 01 (cx) 02 ,cy 02 (cx) 03 ,cy 03If the coordinates of the first center point (cx0, cy0) are given by the following formula:

[0046] cx0 = (cx 00 +cx 01 +cx 02 +cx 03 ) / 4

[0047] cy0 = (cy 00 +cy 01 +cy 02 +cy 03 ) / 4

[0048] The first pixel size includes a first pixel width w0 and / or a first pixel height h0. The first pixel width w0 is the distance between two feature points selected in the same horizontal direction in the image captured by the zoom module. In this embodiment, the center points of two symmetrical first black and white corner dot patterns 2 in the horizontal direction are used as the two feature points of the first pixel width; of course, other feature points can also be used. The first pixel height h0 is the distance between two feature points selected in the same vertical direction in the image captured by the zoom module. In this embodiment, the center points of two symmetrical first black and white corner dot patterns 2 in the vertical direction can be used as the two feature points of the first pixel height; of course, other feature points can also be used.

[0049] The first rotation matrix is ​​a rotation parameter matrix calculated based on the coordinates of the center points of the four first black and white corner point patterns 2 in the imaging image of the zoom module. The coordinates of the center points of the four first black and white corner point patterns 2 in the imaging image of the zoom module can be calculated using Perspective-n-Point (PnP) to obtain the attitude parameters [R0, T0] of the zoom module. Here, R0 is the rotation parameter matrix of the zoom module obtained through the above calculation, i.e., the first rotation matrix; T0 is the translation parameter matrix of the zoom module obtained through the above calculation, which is not required in this embodiment.

[0050] The PnP algorithm is a computer vision algorithm used to calculate camera pose. It calculates the camera pose, i.e., the camera's rotation and translation parameter matrices, based on known 3D point coordinates and corresponding 2D image point coordinates. In this embodiment, the center point coordinates of the four first black and white corner point patterns 2 can be converted from 2D coordinates to 3D coordinates. Since the center points of the four first black and white corner point patterns 2 are all located on the known planar graphic of the calibration board, the depth (i.e., Z-coordinate) of the center points of the four first black and white corner point patterns 2 can be defined as 0, thus converting the center point coordinates of the four first black and white corner point patterns 2 from 2D coordinates to 3D coordinates. Inputting the 2D and 3D coordinates of the center points of the four first black and white corner point patterns 2 into the relevant software of the PnP algorithm outputs the corresponding rotation parameter matrix (i.e., matrix R0) and translation parameter matrix (i.e., matrix T0), thereby obtaining the zoom module's pose parameters [R0, T0].

[0051] The image parameters of the wide-angle module may include the second center point coordinates, the second pixel size, and the second rotation matrix. The second center point coordinates are the center point coordinates of a rectangular area calculated based on the center point coordinates of the four first black and white corner point patterns 2 in the wide-angle module's image. For example, the second center point coordinates can be obtained by averaging the center point coordinates of the four first black and white corner point patterns 2 in the wide-angle module's image. Assume the center point coordinates of the four first black and white corner point patterns 2 in the wide-angle module's image are (cx... 10 ,cy 10 (cx) 11 ,cy 11 (cx) 12 ,cy 12 (cx) 13 ,cy 13 Then, the coordinates of the second center point (cx1cy1) can be obtained by the following formula:

[0052] Cx1 = (cx 10 +cx 11 +cx 12 +cx 13 ) / 4

[0053] Cy1 = (cy 10 +cy 11 +cy 12 +cy 13 ) / 4

[0054] The second pixel size includes a second pixel width w1 and / or a second pixel height h1. The second pixel width w1 is the distance between two feature points corresponding to the first pixel width in the image of the wide-angle module (i.e., the distance between the center points of two symmetrical first black and white corner dot patterns 2 in the horizontal direction). The second pixel height h1 is the distance between two feature points corresponding to the first pixel height in the image of the wide-angle module (i.e., the distance between the center points of two symmetrical first black and white corner dot patterns 2 in the vertical direction).

[0055] The second rotation matrix is ​​a rotation parameter matrix calculated based on the coordinates of the center points of the four first black and white corner point patterns 2 in the imaging image of the wide-angle module. The Perspective-n-Point (PnP) algorithm can be used to calculate the coordinates of the center points of the four first black and white corner point patterns 2 in the imaging image of the wide-angle module, obtaining the attitude parameters [R1, T1] of the wide-angle module. Here, R1 is the rotation parameter matrix of the wide-angle module obtained through the above calculation, i.e., the second rotation matrix; T1 is the translation parameter matrix of the wide-angle module obtained through the above calculation, which is not required in this embodiment. The method for calculating the attitude parameters [R1, T1] of the wide-angle module using the PnP algorithm is the same as the method for calculating the attitude parameters [R0, T0] of the zoom module, and will not be described in detail here.

[0056] To perform optical axis centering correction on the thermal imaging module, the image parameters of the zoom module also include the third center point coordinates, the third pixel size, and the third rotation matrix. The third center point coordinates are the center point coordinates of a rectangular area calculated based on the center point coordinates of the four second black-and-white corner dot patterns 3 in the zoom module's image. For example, the third center point coordinates can be obtained by averaging the center point coordinates of the four second black-and-white corner dot patterns 3 in the zoom module's image. Assume the center point coordinates of the four second black-and-white corner dot patterns 3 in the zoom module's image are (cx... 20 ,cy 20 (cx) 21 ,cy 21 (cx) 22 ,cy 22 (cx) 23 ,cy 23 Then the coordinates of the third center point (cx2, cy2) can be obtained by the following formula:

[0057] Cx2 = (cx 20 +cx 21 +cx 22 +cx 23 ) / 4

[0058] Cy2=(cy 20 +cy21 +cy 22 +cy 23 ) / 4

[0059] The third pixel size includes a third pixel width w2 and / or a third pixel height h2. The third pixel width w2 is the distance between the center points of two symmetrical second black and white corner dot patterns 3 in the horizontal direction in the image of the zoom module. The third pixel height h2 is the distance between the center points of two symmetrical second black and white corner dot patterns 3 in the vertical direction in the image of the zoom module.

[0060] The third rotation matrix is ​​a rotation parameter matrix calculated based on the coordinates of the center points of the four second black and white corner point patterns 3 in the imaging image of the zoom module. The Perspective-n-Point (PnP) algorithm can be used to calculate the coordinates of the center points of the four second black and white corner point patterns 3 in the imaging image of the zoom module to obtain the attitude parameters [R2, T2] of the zoom module. Here, R2 is the rotation parameter matrix of the zoom module obtained through the above calculation, i.e., the third rotation matrix; T2 is the translation parameter matrix of the zoom module obtained through the above calculation, which is not required in this embodiment. The method for calculating the attitude parameters [R2, T2] of the zoom module using the PnP algorithm is the same as the method for calculating the attitude parameters [R0, T0] of the zoom module, and will not be described in detail here.

[0061] The image parameters of the thermal imaging module include the fourth center point coordinates, the fourth pixel size, and the fourth rotation matrix. The fourth center point coordinates are the center point coordinates of a rectangular area calculated based on the center point coordinates of the four isothermal metal rods 4 in the thermal imaging module's image. For example, the fourth center point coordinates can be obtained by averaging the center point coordinates of the four second black and white corner pattern 3 in the zoom module's image. Assume the center point coordinates of the four second black and white corner pattern 3 in the zoom module's image are (cx... 30 ,cy 30 (cx) 31 ,cy 31 (cx) 32 ,cy 32 (cx) 33 ,cy 33 Then the coordinates of the fourth center point (cx3, cy3) can be obtained by the following formula:

[0062] Cx3 = (cx 30 +cx 31 +cx 32 +cx 33 ) / 4

[0063] Cy3 = (cy 30 +cy31 +cy 32 +cy 33 ) / 4

[0064] The fourth pixel size includes a fourth pixel width w3 and / or a fourth pixel height h3. The fourth pixel width w3 is the distance between the center points of two horizontally symmetrical isothermal metal rods 4 in the imaging image of the thermal imaging module. The fourth pixel height h3 is the distance between the center points of two vertically symmetrical isothermal metal rods 4 in the imaging image of the thermal imaging module.

[0065] The fourth rotation matrix is ​​a rotation parameter matrix calculated based on the coordinates of the center points of the four isothermal metal rods 4 in the imaging image of the thermal imaging module. The Perspective-n-Point (PnP) algorithm can be used to calculate the coordinates of the center points of the four second black and white corner point patterns 3 in the imaging image of the thermal imaging module, obtaining the attitude parameters [R3, T3] of the thermal imaging module. Here, R3 is the rotation parameter matrix of the thermal imaging module obtained through the above calculation, i.e., the fourth rotation matrix; T3 is the translation parameter matrix of the thermal imaging module obtained through the above calculation, which is not required in this embodiment. The method for calculating the attitude parameters [R3, T3] of the thermal imaging module using the PnP algorithm is the same as the method for calculating the attitude parameters [R0, T0] of the zoom module, and will not be described in detail here.

[0066] To perform optical axis centering correction on the laser ranging module, the image parameters of the zoom module (i.e., the standard module) also include a fifth center coordinate, which is the coordinate of the center point (cx4, cy4) in the image of the zoom module. For example, half the width of the image of the standard module can be used as the x-axis coordinate of the fifth center coordinate; and half the height of the image of the standard module can be used as the y-axis coordinate of the fifth center coordinate.

[0067] The center coordinates of the laser spot are used as the image parameters of the laser ranging module. These center coordinates are the coordinates (cx5, cy5) of the center point of the laser spot pattern formed on the laser observation card 5 by the laser emitted by the laser ranging module. The method for calculating the center coordinates of the laser spot is as follows: A zoom module is used to continuously image the calibration board 1, obtaining multiple images frame0, frame1, frame2, ..., frame... n The first image, frame0, is the image taken when no laser spot pattern has formed on the laser observation card 5. The first image, frame0, is subtracted sequentially from the remaining images to obtain multiple difference images, frame. diff , such as frame diff1 =sum|frame0-frame1|, frame diff2= sum |frame0-frame2|,…,framediff n = sum |frame0-frame n Find the maximum value in the difference image, locate the laser spot pattern from the difference image, and calculate the coordinates of the center point of the laser spot pattern.

[0068] Since the laser spot pattern formed by the laser ranging module on the laser observation card 5 is presented intermittently, in order to avoid the zoom module not being able to capture the complete display of the laser spot pattern, a continuous imaging method is adopted, so that there is always an image that can capture the complete display of the laser spot pattern. Thus, the laser spot pattern can be found by subtracting the images, and then the center coordinates of the laser spot can be calculated.

[0069] S400. The relative parameters of the remaining imaging modules are calculated based on the image parameters of the standard module and the image parameters of the other imaging modules. These relative parameters include pixel translation parameters, focal length magnification parameters, and pixel transfer parameters. The pixel translation parameters of each remaining imaging module are calculated based on the center point coordinates of its image parameters and the center point coordinates of the standard module's image parameters. The focal length magnification parameters of each remaining imaging module are calculated based on the pixel size of its image parameters and the pixel size of the standard module's image parameters. The pixel transfer parameters of each remaining imaging module are calculated based on the rotation parameter matrix of its image parameters and the rotation parameter matrix of the standard module's image parameters.

[0070] Specifically, the relative parameters of the wide-angle module may include a first pixel translation parameter, a first focal length magnification parameter, and a first pixel shift parameter. The first pixel translation parameter is calculated based on the coordinates of a first center point and a second center point. For example, the first pixel translation parameter can be the difference between the coordinates of the second center point and the coordinates of the first center point; that is, [cx1, cy1] - [cx0, cy0], which includes two elements: a horizontal coordinate translation value (cx1 - cx0) and a vertical coordinate translation value (cy1 - cy0).

[0071] The first focal length magnification parameter is calculated based on the first pixel size and the second pixel size. For example, the first focal length magnification parameter can be the ratio of the second pixel size to the first pixel size, i.e., [w1,h1] / [w0,h0], which can include two elements: width magnification and height magnification. Of course, since the width magnification and height magnification are generally basically the same, either the width magnification w1 / w0 or the height magnification h1 / h0 can be taken as the first focal length magnification parameter.

[0072] The first pixel transfer parameter R 01It is calculated based on the first rotation matrix R0 and the second rotation matrix R1. For example: the first pixel transfer parameter R 01 It can be the second rotation matrix R1 and the transpose of the first rotation matrix R0 T Multiplying them together gives us R. 01 = R1R0 T .

[0073] Of course, multiple sets of the first corner point group can be set to obtain multiple sets of test results, so as to combine multiple sets of test results to improve the optical axis center correction accuracy of the wide-angle module.

[0074] The relative parameters of the thermal imaging module include the second pixel translation parameter, the second focal length magnification parameter, and the second pixel transfer parameter.

[0075] The second pixel translation parameter is calculated based on the coordinates of the third center point and the fourth center point. For example, the second pixel translation parameter can be the difference between the coordinates of the fourth center point and the coordinates of the third center point; that is, [cx3, cy3] - [cx2, cy2], which includes two elements: the horizontal coordinate translation value (cx3 - cx2) and the vertical coordinate translation value (cy3 - cy2).

[0076] The second focal length magnification parameter is calculated based on the third and fourth pixel dimensions. For example, the second focal length magnification parameter can be the ratio of the fourth pixel dimension to the third pixel dimension, i.e., [w3,h3] / [w2,h2], which can include two elements: width magnification and height magnification. Of course, since the width magnification and height magnification are generally basically the same, either the width magnification w3 / w2 or the height magnification h3 / h2 can be used as the second focal length magnification parameter.

[0077] The second pixel transfer parameter R 02 It is calculated based on the third rotation matrix R2 and the fourth rotation matrix R3. For example: the second pixel transfer parameter R 02 It can be the fourth rotation matrix R3 and the transpose of the third rotation matrix R2. T Multiplying them together gives us R. 02 = R3R2 T .

[0078] Of course, multiple sets of the second corner point group and the constant temperature metal rod 4 can be set to obtain multiple sets of test results, so as to integrate multiple sets of test results to improve the optical axis center correction accuracy of the thermal imaging module.

[0079] The relative parameters of the laser ranging module include a third pixel translation parameter, which is the difference between the coordinates of the laser spot center and the fifth center coordinate. That is, [cx5, cy5] - [cx4, cy4], which includes two elements: the horizontal coordinate translation value (cx5 - cx4) and the vertical coordinate translation value (cy5 - cy4).

[0080] S500, based on the relative parameters of the remaining imaging modules (i.e., the wide-angle module, the thermal imaging module) and the laser ranging module, corrects the optical axis deviation through software and image processing algorithms, and calibrates the optical axis centers of the remaining imaging modules and the laser ranging module. The relative parameters of the wide-angle module, the thermal imaging module, and the laser ranging module can be stored after calibration. During imaging, the relative parameters are retrieved through software to calibrate the optical axis centers of the wide-angle module, the thermal imaging module, and the laser ranging module. The calibration process includes the following sub-steps:

[0081] S510. After each imaging module performs imaging, the coordinates of the pixels in the imaging images of the remaining imaging modules (excluding the standard module) are translated according to the pixel translation parameters and the focal length magnification during imaging, to obtain the coordinates of the pixels in the imaging images of the remaining imaging modules after the first step of correction; and the optical axis center of the laser ranging module is calibrated according to the relative parameters of the laser ranging module. In this embodiment, after each imaging module performs imaging and the laser ranging module performs ranging, the imaging images of the wide-angle module and the thermal imaging module are corrected in the first step according to the first pixel translation parameters, the second pixel translation parameters, the third pixel translation parameters and the focal length magnification during imaging (ranging), and the ranging point position of the laser ranging module is corrected.

[0082] For example, for the wide-angle module, the product of the horizontal coordinate shift value (cx1-cx0) in the first pixel translation parameter and the focal length magnification is used as its horizontal offset, and the product of the vertical coordinate shift value (cy1-cy0) in the first pixel translation parameter and the focal length magnification is used as its vertical offset. The horizontal offset is subtracted from the horizontal coordinate of each pixel in the image to obtain the horizontal coordinate of the pixel in the first step of correction, and the vertical offset is subtracted from the vertical coordinate of each pixel in the image to obtain the vertical coordinate of the pixel in the first step of correction. This completes the first step of correction for the wide-angle module. The method for the first step of correction for the thermal imaging module based on the second pixel translation parameter is basically the same as that for the wide-angle module, and will not be elaborated here.

[0083] When correcting the ranging point position of the laser ranging module based on the third pixel translation parameter, the lateral and vertical offsets are first calculated using the third pixel translation parameter and the focal length magnification, in the same way as the wide-angle module. Then, the horizontal offset of the laser ranging module is added to the horizontal coordinate of the center point of the zoom module's image to obtain the horizontal coordinate of the laser ranging module's ranging point. Similarly, the vertical offset of the laser ranging module is added to the vertical coordinate of the center point of the zoom module's image to obtain the vertical coordinate of the laser ranging module's ranging point. This gives the corrected coordinate position of the laser ranging module's ranging point.

[0084] S520. The coordinates of pixels in the imaging images of the remaining imaging modules (excluding the standard module) after the first step correction are scaled according to the focal length magnification parameter to obtain the coordinates of pixels in the imaging images of the remaining imaging modules after the second step correction. In this embodiment, the imaging images of the wide-angle module and the thermal imaging module are corrected in the second step according to the first focal length magnification parameter and the second focal length magnification parameter, respectively.

[0085] For example, for a wide-angle module, the x-coordinate of each pixel in its image (i.e., the x-coordinate of the pixel after the first correction) is divided by the width ratio in the first focal length magnification parameter to obtain the x-coordinate of the pixel after the second correction. Similarly, the y-coordinate of each pixel in its image (i.e., the y-coordinate of the pixel after the first correction) is divided by the height ratio in the first focal length magnification parameter to obtain the y-coordinate of the pixel after the second correction. If there is only a uniform first focal length magnification parameter and no distinction is made between width and height magnification, then simply divide both the x-coordinate and y-coordinate of each pixel in the wide-angle module's image by the first focal length magnification parameter. The method for performing the second correction on the thermal imaging module based on the second focal length magnification parameter is basically the same as that for the wide-angle module and will not be elaborated here.

[0086] S530: After normalizing the coordinates of pixels in the imaging images of the imaging modules other than the standard module after the second step correction, they are rotated according to the pixel transfer parameters and reprojected back to the pixel coordinates to obtain the corrected coordinates of pixels in the imaging images of the remaining imaging modules at the optical axis center. In this embodiment, the first pixel transfer parameter R is used respectively. 01 Second pixel transfer parameter R 02 The third step involves correcting the images from the wide-angle module and the thermal imaging module.

[0087] For example, for the wide-angle module, based on the first pixel transfer parameter R 01 The third step of image correction for the wide-angle module mainly involves the following three steps:

[0088] (1) Obtain the normalized coordinate matrix based on the pixel coordinates of the wide-angle module's image. d The formula is as follows:

[0089]

[0090]

[0091]

[0092] in, u This refers to the x-coordinate of the pixel in the image after the second step of correction. v This refers to the ordinate of the pixel in the image after the second step of correction. x , y These are normalized coordinate parameters; c x , c y , f x , f y represents the parameters of the wide-angle module's intrinsic parameter matrix, where c x , c y These are the pixel center coordinate parameters. f x , f y These are the coordinate parameters of the focal center.

[0093] (2) Based on the first pixel transfer parameter R 01 For the normalized coordinate matrix d Rotate to obtain the corrected coordinate matrix. d' The formula is as follows:

[0094]

[0095] in, d' x , d' y , d' z To correct the coordinate matrix d' The parameters.

[0096] (3) Correct the coordinate matrix d' The formula for reprojecting back to pixel coordinates is as follows:

[0097]

[0098]

[0099] in, u' This refers to the x-coordinate of the pixel in the image after the third step of correction. v'This represents the ordinate of the pixel in the image after the third step of correction. This completes the third step of correction, namely, the process of correcting the optical axis center of the wide-angle module.

[0100] According to the second pixel transfer parameter R 02 The third-step calibration method for the thermal imaging module is basically the same as that for the wide-angle module, and will not be elaborated here.

[0101] Then, the imaging images from each imaging module and the measurement data from the laser ranging module are fused together; this fusion process is a conventional existing technology and will not be described in detail here.

[0102] This embodiment has the following beneficial effects:

[0103] 1. Simplified Hardware: Utilizing a simplified structure and low-cost sensors eliminates the need for expensive automatic calibration mechanisms, reducing component costs. Furthermore, through improvements to calibration board 1, all imaging modules and laser ranging modules can be calibrated using the same calibration board 1, eliminating the need for separate, custom-made calibration boards for each module.

[0104] 2. Software compensation: By correcting optical axis deviation through software and image processing algorithms, the labor cost of precision mechanical alignment can be saved.

[0105] 3. High efficiency in mass production: The inexpensive solution can be mass-produced quickly, suitable for multiple airframes or a large number of pods deployed at once.

[0106] 4. Quick on-site adjustment: The optical axis can be aligned using a simple calibration board or natural scene features, eliminating the need for factory fine-tuning.

[0107] 5. Low cost of calibration tools: The calibration process can be completed with only a simple optical standard and general testing software.

[0108] 6. Remote recalibration is possible: By combining image overlay and comparison technology, software recalibration can be performed through ground stations or airborne computing units.

[0109] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A method for optical axis center correction of an electro-optical pod imaging module, the electro-optical pod being provided with an imaging module, characterized in that, The method comprises the following steps: S100, selecting an imaging module as a standard module in an imaging module group, and performing hardware correction on the optical axis center of the standard module; S200, performing imaging on the correction chart by each imaging module in the imaging module group to obtain an imaging image of each imaging module; S300, calculating the image parameters of each imaging module according to the imaging image of each imaging module; the image parameters of each imaging module comprise the center point coordinates, pixel size and rotation parameter matrix of the imaging image of each imaging module; S400, calculating the relative parameters of each remaining imaging module according to the image parameters of the standard module and the image parameters of each remaining imaging module; the relative parameters comprise pixel translation parameters, focal length magnification parameters and pixel transfer parameters; the pixel translation parameters of each remaining imaging module are calculated according to the center point coordinates of the image parameters and the center point coordinates in the image parameters of the standard module; the focal length magnification parameters of each remaining imaging module are calculated according to the pixel size of the image parameters and the pixel size in the image parameters of the standard module; and the pixel transfer parameters of each remaining imaging module are calculated according to the rotation parameter matrix of the image parameters and the rotation parameter matrix in the image parameters of the standard module; S500, respectively calibrating the optical axis center of each remaining imaging module according to the relative parameters of each remaining imaging module; the calibration method comprises the following steps: after imaging is performed on each imaging module, firstly, the coordinates of the pixel points in the imaging image of each remaining imaging module are translated according to the pixel translation parameters and the focal length magnification during imaging, then the translated pixel point coordinates are scaled according to the focal length magnification parameters, and finally, the pixel point coordinates are sequentially normalized, rotated and re-projected according to the pixel transfer parameters.

2. The optical axis center correction method of the electro-optical pod imaging module according to claim 1, wherein, The method for performing hardware correction on the optical axis center of the standard module comprises the following steps: a rectangular area is arranged on the correction chart as an imaging area, and the lens center of the standard module is aligned with the center point of the rectangular area.

3. The optical axis center correction method of a photometric pod imaging module according to claim 2, characterized by: The imaging module group comprises a zoom module, and the zoom module is selected as the standard module; in the S200 step, each imaging module performs imaging on the correction chart at the 1X focal length of the zoom module.

4. The optical axis center correction method of the electro-optical pod imaging module according to claim 3, characterized in that: The imaging module group further comprises a wide-angle module; The rectangular area of the correction chart is provided with a first corner point group, the first corner point group comprises four first black and white corner point patterns, the center points of the four first black and white corner point patterns are respectively located on two diagonal lines of the rectangular area, the center points of the two first black and white corner point patterns on each diagonal line are symmetrically arranged on both sides of the center point of the rectangular area, and the distances between the center points of the four first black and white corner point patterns and the center point of the rectangular area are all equal. The image parameters of the zoom module include a first center point coordinate, a first pixel size, and a first rotation matrix; the first center point coordinate is a center point coordinate of a rectangular region calculated according to center point coordinates of four first black-and-white corner point patterns in an imaging image of the zoom module; the first pixel size includes a first pixel width and / or a first pixel height, the first pixel width is a distance between two feature points selected in the same horizontal direction in the imaging image of the zoom module, and the first pixel height is a distance between two feature points selected in the same vertical direction in the imaging image of the zoom module; and the first rotation matrix is a rotation parameter matrix calculated according to the imaging image of the zoom module. The image parameters of the wide-angle module include a second center point coordinate, a second pixel size, and a second rotation matrix; the second center point coordinate is a center point coordinate of a correction chart calculated according to center point coordinates of the four first black-and-white corner point patterns in the imaging image of the wide-angle module; the second pixel size includes a second pixel width and / or a second pixel height, the second pixel width is a distance between two feature points corresponding to the first pixel width in the imaging image of the wide-angle module, and the second pixel height is a distance between two feature points corresponding to the first pixel height in the imaging image of the wide-angle module; and the second rotation matrix is a rotation parameter matrix calculated according to the imaging image of the wide-angle module. The relative parameters of the wide-angle module include a first pixel translation parameter, a first focal length magnification parameter, and a first pixel transfer parameter; the first pixel translation parameter is calculated according to the first center point coordinate and the second center point coordinate; and the first focal length magnification parameter is calculated according to the first pixel size and the second pixel size. The first pixel transfer parameter is calculated according to the first rotation matrix and the second rotation matrix.

5. The optical axis center correction method of a photometric pod imaging module according to claim 4, characterized by: The four first black-and-white corner point patterns of the first corner point group are located at four corner regions of the rectangular region.

6. The optical axis center correction method of a photometric pod imaging module according to claim 4, characterized by: The first center point coordinate is obtained by averaging center point coordinates of the four first black-and-white corner point patterns in the imaging image of the zoom module, and the second center point coordinate is obtained by averaging center point coordinates of the four first black-and-white corner point patterns in the imaging image of the wide-angle module. The first pixel translation parameter is a difference between the second center point coordinate and the first center point coordinate, and the first focal length magnification parameter is a ratio of the second pixel size to the first pixel size. The first pixel transfer parameter is obtained by multiplying the second rotation matrix and a transpose matrix of the first rotation matrix.

7. The optical axis center correction method of a photometric pod imaging module according to claim 3, characterized by: The imaging module further comprises a thermal imaging module, and a second corner point group is arranged in the rectangular area of the correction board, the second corner point group comprises four second black and white corner point patterns, and center points of the four second black and white corner point patterns are respectively located on two diagonal lines of the rectangular area; the center points of the two second black and white corner point patterns on each diagonal line are symmetrically arranged on two sides of a center point of the rectangular area, and distances between the center points of the four second black and white corner point patterns and the center point of the rectangular area are equal; a constant temperature metal rod is vertically arranged in a middle part of each second black and white corner point pattern, and the center point of the second black and white corner point pattern is located on an axis of the constant temperature metal rod; The image parameters of the zoom module comprise a third center point coordinate, a third pixel size and a third rotation matrix; the third center point coordinate is a center point coordinate of the rectangular area calculated according to center point coordinates of the four second black and white corner point patterns in the imaging image of the zoom module; the third pixel size comprises a third pixel width and / or a third pixel height, the third pixel width is a distance between the center points of the two second black and white corner point patterns symmetrically arranged in the horizontal direction in the imaging image of the zoom module, and the third pixel height is a distance between the center points of the two second black and white corner point patterns symmetrically arranged in the vertical direction in the imaging image of the zoom module; and the third rotation matrix is a rotation parameter matrix calculated according to the center point coordinates of the four second black and white corner point patterns in the imaging image of the zoom module; The image parameters of the thermal imaging module comprise a fourth center point coordinate, a fourth pixel size and a fourth rotation matrix; the fourth center point coordinate is a center point coordinate of the correction board calculated according to center point coordinates of the four constant temperature metal rods in the imaging image of the thermal imaging module; the fourth pixel size comprises a fourth pixel width and / or a fourth pixel height, the fourth pixel width is a distance between the center points of the two constant temperature metal rods symmetrically arranged in the horizontal direction in the imaging image of the thermal imaging module, and the fourth pixel height is a distance between the center points of the two constant temperature metal rods symmetrically arranged in the vertical direction in the imaging image of the thermal imaging module; and the fourth rotation matrix is a rotation parameter matrix calculated according to the center point coordinates of the four constant temperature metal rods in the imaging image of the thermal imaging module; The relative parameters of the thermal imaging module comprise a second pixel translation parameter, a second focal length magnification parameter and a second pixel transfer parameter; the second pixel translation parameter is calculated according to the third center point coordinate and the fourth center point coordinate; and the second focal length magnification parameter is calculated according to the third pixel size and the fourth pixel size; The second pixel transfer parameter is calculated according to the third rotation matrix and the fourth rotation matrix.

8. The optical axis center correction method of a photometric pod imaging module according to claim 7, characterized by: The third center point coordinate is obtained by averaging the center point coordinates of four second black and white corner point patterns in the imaging image of the zoom module, and the fourth center point coordinate is obtained by averaging the center point coordinates of four constant temperature metal rods in the imaging image of the thermal imaging module; the second pixel translation parameter is the difference between the fourth center point coordinate and the third center point coordinate; and the second focal length magnification parameter is the ratio of the fourth pixel size to the third pixel size. The second pixel translation parameter is obtained by multiplying the fourth rotation matrix and the transpose matrix of the third rotation matrix.

9. The optical axis center correction method of a photometric pod imaging module according to any one of claims 1 to 8, characterized by: The optoelectronic pod further comprises an auxiliary imaging module, the auxiliary imaging module comprises a laser ranging module, and the middle part of the correction graph board is provided with a laser observation card; the image parameters of the standard module include a fifth center coordinate, and the fifth center coordinate is the center point coordinate of the imaging image of the standard module; in the S200 step, the laser ranging module also emits laser to the laser observation card, in the S300 step, the laser spot center coordinate is taken as the image parameter of the laser ranging module, the laser spot center coordinate is the center point coordinate of the laser spot pattern formed by the laser emitted by the laser ranging module on the laser observation card; the relative parameters of the laser ranging module include a third pixel translation parameter, and the third pixel translation parameter is the difference between the laser spot center coordinate and the fifth center coordinate; in the S500 step, the optical axis center of the laser ranging module is also calibrated according to the relative parameters of the laser ranging module.

10. The optical axis center correction method of the electro-optical pod imaging module according to claim 9, wherein, The method for calculating the fifth center coordinate is that half of the width of the imaging image of the standard module is taken as the x-axis coordinate of the fifth center coordinate, and half of the height of the imaging image of the standard module is taken as the y-axis coordinate of the fifth center coordinate. The method for calculating the laser spot center coordinate is that the correction graph board is continuously imaged by using the standard module to obtain a plurality of images, and the first image of the continuous imaging is subtracted from the remaining images in turn to obtain a plurality of difference images, the maximum value of the difference images is found out, the laser spot pattern is found out from the difference image, and the center point coordinate of the laser spot pattern is calculated.

Images