Camera intrinsic parameter calibration device and method

Abstract

The present application provides a camera intrinsic parameter calibration device and method, the device includes: an intrinsic parameter calibration stand and multiple calibration plates, the multiple calibration plates are arranged inside the intrinsic parameter calibration stand, the shape of the internal parameter calibration stand is a cuboid, the ratio of the width and height of the internal parameter calibration stand is equal to the ratio of the horizontal field of view angle and the vertical field of view angle of the camera, the angle range between the multiple calibration plates and the top surface of the internal parameter calibration stand is ≥0° and ≤90°, and the orthographic projections of the multiple calibration plates on either side of the internal parameter calibration stand are at least partially non-overlapping. Therefore, by setting multiple calibration plates at different distances and different positions and postures, it is only necessary to collect a graphic containing multiple calibration plates to perform camera intrinsic parameter calibration, which is time-saving, simple in process, and improves efficiency.

Description

Technical Field

[0001] The present application relates to the field of camera calibration, and in particular to a camera intrinsic parameter calibration device and method. Background Art

[0002] In order to determine the relationship between the three-dimensional coordinate points of a spatial object and its two-dimensional coordinate points in the camera image, a geometric model of camera imaging must be established. These geometric model parameters are the camera parameters. The process of solving the camera parameters is called camera calibration. Camera calibration is divided into internal parameter calibration and external parameter calibration. The camera internal parameters are determined by the properties of the camera itself and have nothing to do with the installation position.

[0003] Traditional camera intrinsic parameters are generally calibrated using the checkerboard method, which means collecting multiple checkerboard images at different distances and positions for calibration. For example, dozens of images must be collected to accurately solve the intrinsic parameters, resulting in a long calibration time, a cumbersome process, and difficulty in industrial application. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a camera intrinsic parameter calibration device and method, which can accurately solve the camera intrinsic parameters while taking a short time and having a simple process.

[0005] To achieve the above purpose, this application has the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides a camera intrinsic parameter calibration device, comprising: an intrinsic parameter calibration stand and a plurality of calibration plates; the plurality of calibration plates are arranged inside the intrinsic parameter calibration stand;

[0007] The shape of the internal parameter calibration rig is a cuboid; the ratio of the width to the height of the internal parameter calibration rig is equal to the ratio of the horizontal field of view angle to the vertical field of view angle of the camera;

[0008] The angle between the multiple calibration plates and the top surface of the internal reference calibration stand is in the range of ≥0° and ≤90°;

[0009] The orthographic projections of the plurality of calibration plates on any side of the internal reference calibration stand are at least partially non-overlapping.

[0010] In a possible implementation, the angle between the multiple calibration plates and the top surface of the internal reference calibration stand is in a range of ≥0° and ≤90°, including:

[0011] The angle between the multiple calibration plates and the top surface of the internal reference calibration stand is in the range of ≥20° and ≤70°.

[0012] In a possible implementation, the plurality of calibration plates include: a first calibration plate, a second calibration plate, a third calibration plate, a fourth calibration plate, a fifth calibration plate, a sixth calibration plate, a seventh calibration plate, and an eighth calibration plate;

[0013] The angle between the first calibration plate and the second calibration plate and the top surface of the calibration stand is 40°; the angle between the third calibration plate and the fourth calibration plate and the top surface of the calibration stand is 0°; the angle between the fifth calibration plate and the sixth calibration plate and the top surface of the calibration stand is 50°; the angle between the seventh calibration plate and the eighth calibration plate and the top surface of the calibration stand is 60°.

[0014] In a possible implementation, the device further includes: a camera fixing device;

[0015] The camera fixing device is located on the outside of one side of the internal reference calibration platform, and the orthographic projection of the camera fixing device on the one side is at the intersection of the diagonal line of the one side.

[0016] In a possible implementation, the orthographic projections of the first calibration plate and the second calibration plate on one side of the internal reference calibration rig are the first projection; the orthographic projections of the third calibration plate and the fourth calibration plate on one side of the internal reference calibration rig are the second projection; the orthographic projections of the fifth calibration plate and the sixth calibration plate on one side of the internal reference calibration rig are the third projection; the orthographic projections of the seventh calibration plate and the eighth calibration plate on one side of the internal reference calibration rig are the fourth projection;

[0017] The area of ​​the first projection that does not overlap with other projections accounts for 50% of the total projection area of ​​the multiple calibration plates; the area of ​​the second projection that does not overlap with other projections accounts for 16.6% of the total projection area of ​​the multiple calibration plates; the area of ​​the third projection that does not overlap with other projections accounts for 16.6% of the total projection area of ​​the multiple calibration plates; the area of ​​the fourth projection that does not overlap with other projections accounts for 16.6% of the total projection area of ​​the multiple calibration plates.

[0018] In a second aspect, an embodiment of the present application provides a camera intrinsic parameter calibration method, including:

[0019] Acquire images of the plurality of calibration plates as described above;

[0020] Establishing the world coordinate systems of the multiple calibration plates respectively;

[0021] Using a corner point recognition algorithm to identify the corner points of each of the plurality of calibration plates;

[0022] After matching the corner point coordinates of the corner points with the world coordinates in the world coordinate system one by one, the camera intrinsic parameter result is obtained by using Zhang Zhengyou calibration method.

[0023] In a possible implementation manner, the image is a grayscale image.

[0024] In a possible implementation, the corner point recognition algorithm includes: Harris algorithm.

[0025] In a possible implementation, the calibration plate is a checkerboard calibration plate; and the step of using a corner point recognition algorithm to recognize corner points of each of the plurality of calibration plates includes:

[0026] Locate the coordinate origin and the length of each checkerboard in the checkerboard calibration plate in the image;

[0027] Using a corner point recognition algorithm to identify corner points in the image;

[0028] The corner points in the image are sorted and screened; the screening includes: if the distance between the next corner point and the previous corner point exceeds the length of each chessboard in the image, then the next corner point is excluded;

[0029] The corner points in the filtered image are used as the corner points of each of the multiple calibration plates.

[0030] In a possible implementation manner, the adopting a corner point recognition algorithm to recognize corner points in the image includes:

[0031] A corner point recognition algorithm is used to recognize initial corner points in the image, and the initial corner points are refined to sub-pixels to obtain corner points in the image.

[0032] The embodiment of the present application provides a camera intrinsic parameter calibration device and method, the device includes: an intrinsic parameter calibration stand and multiple calibration plates, the multiple calibration plates are arranged inside the intrinsic parameter calibration stand, the shape of the intrinsic parameter calibration stand is a cuboid, the ratio of the width and height of the intrinsic parameter calibration stand is equal to the ratio of the horizontal field of view angle and the vertical field of view angle of the camera, the angle range between the multiple calibration plates and the top surface of the intrinsic parameter calibration stand is >0° and ≤90°, and the orthographic projections of the multiple calibration plates on any side of the intrinsic parameter calibration stand are at least partially non-overlapping. Therefore, by setting multiple calibration plates at different distances and different positions and postures, it is only necessary to collect a graphic containing multiple calibration plates to perform camera intrinsic parameter calibration, which is time-saving, simple in process, and improves efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1A schematic diagram of a camera intrinsic parameter calibration device provided in an embodiment of the present application is shown;

[0035] Figure 2A A schematic diagram showing angles formed between a plurality of calibration plates and a top surface of an intrinsic calibration stand in a camera intrinsic calibration device provided in an embodiment of the present application is shown;

[0036] Figure 2B A schematic diagram showing the angles formed by the third calibration plate and the fourth calibration plate and the side surface of the intrinsic calibration stand in a camera intrinsic calibration device provided in an embodiment of the present application;

[0037] Figure 3 A flow chart of a camera intrinsic parameter calibration method provided in an embodiment of the present application is shown;

[0038] Figure 4 A schematic diagram of a checkerboard calibration plate provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0040] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0041] As described in the background technology, in order to determine the relationship between the three-dimensional coordinate points of a spatial object and its two-dimensional coordinate points in the camera image, a geometric model of camera imaging must be established. These geometric model parameters are the camera parameters. The process of solving the camera parameters is called camera calibration. Camera calibration is divided into intrinsic calibration and extrinsic calibration. The camera intrinsic parameters are determined by the properties of the camera itself and have nothing to do with the installation position.

[0042] Traditional camera intrinsic parameters are generally calibrated using the checkerboard method, which means collecting multiple checkerboard images at different distances and positions for calibration. For example, dozens of images must be collected to accurately solve the intrinsic parameters, resulting in a long calibration time, a cumbersome process, and difficulty in industrial application.

[0043] In order to solve the above technical problems, the present application provides a camera intrinsic parameter calibration device and method, the device includes: an intrinsic parameter calibration stand and multiple calibration plates, the multiple calibration plates are arranged inside the internal parameter calibration stand, the shape of the internal parameter calibration stand is a rectangular parallelepiped, the ratio of the width and height of the internal parameter calibration stand is equal to the ratio of the horizontal field of view angle and the vertical field of view angle of the camera, the angle range between the multiple calibration plates and the top surface of the internal parameter calibration stand is ≥0° and ≤90°, and the orthographic projections of the multiple calibration plates on any side of the internal parameter calibration stand are at least partially non-overlapping. Therefore, by setting multiple calibration plates at different distances and different positions and postures, it is only necessary to collect a graphic containing multiple calibration plates to perform camera intrinsic parameter calibration, which is time-saving, simple in process, and improves efficiency.

[0044] In order to better understand the technical solution and technical effects of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.

[0045] Exemplary Devices

[0046] See also Figure 1 As shown in FIG. 1 , this figure is a schematic diagram of a camera intrinsic parameter calibration device provided in an embodiment of the present application, including:

[0047] Internal reference calibration stand 0 and multiple calibration plates, Figure 1 For the convenience of explanation, multiple calibration plates are separately illustrated for explanation. In actual application, multiple calibration plates are arranged inside the internal reference calibration stand 0.

[0048] In the embodiment of the present application, the shape of the internal parameter calibration stand 0 is a rectangular parallelepiped. In order to make the imaging of the calibration plate just cover the picture taken by the camera and improve the accuracy of the camera internal parameter calibration, the ratio of the width and height of the internal parameter calibration stand 0 can be equal to the ratio of the horizontal field of view angle and the vertical field of view angle of the camera. Among them, the camera can be fixed on a camera fixing device (not shown in the figure) during shooting, and the camera fixing device is located on the outside of one side of the internal parameter calibration stand 0, and the orthographic projection of the camera fixing device on one side of the internal parameter calibration stand 0 is at the intersection of the diagonal lines on one side of the internal parameter calibration stand 0.

[0049] The angle range between the multiple calibration plates and the top surface of the internal parameter calibration rig 0 is ≥0° and ≤90°, so that the camera can capture the pattern on the calibration plate to perform internal parameter calibration on the camera. In a possible implementation, the calibration plate can be a checkerboard calibration plate. At the same time, the orthographic projections of the multiple calibration plates on either side of the internal parameter calibration rig 0 are at least partially non-overlapping, so that the multiple calibration plates are at different distances from the camera and are in different positions and postures. Only one image containing multiple calibration plates needs to be collected to perform camera internal parameter calibration, which is time-saving, simple in process, and improves efficiency.

[0050] In a possible implementation, in order to achieve better shooting effects, the angle range between the multiple calibration plates and the top surface of the intrinsic reference calibration stand 0 may be set to ≥20° and ≤70°, so as to obtain more accurate camera intrinsic references.

[0051] In one possible implementation, see Figure 1 As shown, the plurality of calibration plates may include: a first calibration plate 11 , a second calibration plate 12 , a third calibration plate 13 , a fourth calibration plate 14 , a fifth calibration plate 21 , a sixth calibration plate 22 , a seventh calibration plate 31 and an eighth calibration plate 32 . The internal reference calibration stand 0 is divided into three planes, namely the front surface 1, the middle surface 2 and the back surface 3, wherein one side of the first calibration plate 11 is located in the front surface 1, and the angle between the first calibration plate 11 and the top surface of the calibration stand 0 is 40°; one side of the second calibration plate 12 is located in the front surface 1, and the angle between the second calibration plate 12 and the top surface of the calibration stand 0 is 40°; one side of the third calibration plate 13 is located in the front surface 1, and the angle between the third calibration plate 13 and the top surface of the calibration stand 0 is 0°; one side of the fourth calibration plate 14 is located in the front surface 1, and the angle between the fourth calibration plate 14 and the top surface of the calibration stand 0 is 0°; that is, the angle between the third calibration plate 13 and the side surface 4 of the calibration stand 0 is 30°; one side of the fourth calibration plate 14 is located in the front surface 1, and the angle between the fourth calibration plate 14 and the side surface 5 of the calibration stand 0 is 30°; one side of the fifth calibration plate 21 is located in the middle surface 2, and the angle between the fifth calibration plate 21 and the top surface of the calibration stand 0 is 50°; one side of the sixth calibration plate 22 is located in the middle surface 2, and the angle between the sixth calibration plate 22 and the top surface of the calibration stand 0 is 50°; one side of the seventh calibration plate 31 is located in the back surface 3, and the angle between the seventh calibration plate 31 and the top surface of the calibration stand 0 is 60°; one side of the eighth calibration plate 32 is located in the back surface 3, and the angle between the eighth calibration plate 32 and the top surface of the calibration stand 0 is 60°, see specifically Figure 2A and Figure 2B As shown, it is a schematic diagram of the angles formed by multiple calibration plates in a camera intrinsic parameter calibration device and the top surface of the intrinsic parameter calibration stand 0 provided in an embodiment of the present application, and a schematic diagram of the angles formed by the third calibration plate and the fourth calibration plate in a camera intrinsic parameter calibration device and the side surface of the intrinsic parameter calibration stand.

[0052] In addition, the above-mentioned multiple calibration plates and the camera can be set at different distances, and the above-mentioned multiple calibration plates are in different positions and postures, that is, the orthographic projection of the first calibration plate 11 and the second calibration plate 12 on one side of the internal reference calibration stand 0 is the first projection; the orthographic projection of the third calibration plate 13 and the fourth calibration plate 14 on one side of the internal reference calibration stand 0 is the second projection; the orthographic projection of the fifth calibration plate 21 and the sixth calibration plate 22 on one side of the internal reference calibration stand 0 is the third projection; the orthographic projection of the seventh calibration plate 31 and the eighth calibration plate 32 on one side of the internal reference calibration stand 0 is the fourth projection.

[0053] There is at least partial non-overlap between the first projection, the second projection, the third projection and the fourth projection. The area of ​​the first projection that does not overlap with other projections accounts for 50% of the total projection area of ​​multiple calibration plates; the area of ​​the second projection that does not overlap with other projections accounts for 16.6% of the total projection area of ​​multiple calibration plates; the area of ​​the third projection that does not overlap with other projections accounts for 16.6% of the total projection area of ​​multiple calibration plates; the area of ​​the fourth projection that does not overlap with other projections accounts for 16.6% of the total projection area of ​​multiple calibration plates. Only one image of the multiple calibration plates recorded above needs to be collected to perform camera intrinsic calibration, which is time-saving and simple in process, and can be applied to camera intrinsic process calibration.

[0054] The present application provides a camera intrinsic parameter calibration device, which includes: an intrinsic parameter calibration stand and multiple calibration plates, the multiple calibration plates are arranged inside the intrinsic parameter calibration stand, the shape of the internal parameter calibration stand is a cuboid, the ratio of the width and height of the internal parameter calibration stand is equal to the ratio of the horizontal field of view angle and the vertical field of view angle of the camera, the angle range between the multiple calibration plates and the top surface of the internal parameter calibration stand is ≥0° and ≤90°, and the orthographic projections of the multiple calibration plates on either side of the internal parameter calibration stand are at least partially non-overlapping. Therefore, by setting multiple calibration plates at different distances and different positions and postures, it is only necessary to collect a graphic containing multiple calibration plates to perform camera intrinsic parameter calibration, which is time-saving, simple in process, and improves efficiency.

[0055] Exemplary Methods

[0056] See also Figure 3 As shown in FIG. 1 , the figure is a flow chart of a camera intrinsic parameter calibration method provided in an embodiment of the present application, including:

[0057] S101: Acquire images of multiple calibration plates of the camera intrinsic parameter calibration device.

[0058] In an embodiment of the present application, when performing camera intrinsic parameter calibration, it is first necessary to capture images of multiple calibration plates to calibrate the camera intrinsic parameters. Specifically, the first captured image can be a color image in RGB format. In order to reduce memory overhead and computational complexity, the color image can be converted into a grayscale image.

[0059] It should be noted that the embodiment of the present application does not specifically limit the format of the captured image, for example, it can be a raw format, etc., which can be specifically set by those skilled in the art according to actual conditions.

[0060] S102: Establishing world coordinate systems of the multiple calibration plates respectively.

[0061] See also Figure 4 , which is a schematic diagram of a checkerboard calibration plate provided in an embodiment of the present application.

[0062] A world coordinate system is established in the checkerboard calibration plate provided in the present application. Three circular feature points a, b, and c can be added to the checkerboard calibration plate. The world coordinate system of the calibration plate is established through the three feature points. The origin of the coordinate system is o, the positive direction of the x-axis is oc, and the positive direction of the y-axis is oa. Thus, respective world coordinate systems can be established on multiple calibration plates.

[0063] S102: using a corner point recognition algorithm to recognize corner points of the plurality of calibration plates.

[0064] In an embodiment of the present application, in order to improve the efficiency of corner point recognition on the calibration plate, a region of interest (ROI) can be set for each calibration plate, and the corner points of each calibration plate can be identified separately. The circular and square grids can be distinguished by roundness to identify circular feature points.

[0065] At the same time, the coordinate origin and the length of each checkerboard in the checkerboard calibration plate can also be located in the image, and the corner points in the ROI area can be identified using a corner point recognition algorithm such as the Harris algorithm. At the same time, in order to make the corner point recognition more accurate and improve the detection accuracy of the corner points, the corner point recognition algorithm can be used to identify the initial corner points in the captured image, and the initial corner points can be refined to sub-pixels to obtain the corner points in the image.

[0066] In addition, the corner points in the image can also be sorted and screened, and the screening includes: if the distance between the next corner point and the previous corner point exceeds the length of each chessboard in the image, the next corner point is excluded, that is, with the coordinate origin as the center, the corner points are screened along the x, y, -x and -y directions; if the distance between the next corner point and the previous corner point exceeds the length of each chessboard in the image, the corner point that does not meet the requirement is excluded, and the corner points in the screened image are used as the corner points of each calibration plate, so that the corresponding corner points of each calibration plate can be accurately identified, and the image of the calibration plate can be accurately formed for subsequent calibration of the camera intrinsic parameters, avoiding misidentification of corner points on other calibration plates, which is conducive to accurate calibration of the camera intrinsic parameters.

[0067] S103: After matching the corner point coordinates of the corner points with the world coordinates in the world coordinate system one by one, the camera intrinsic parameter result is obtained by using the Zhang Zhengyou calibration method.

[0068] In the embodiment of the present application, after identifying the corner point coordinates of each calibration plate, the corner point coordinates can be matched one-to-one with the world coordinates of the established world coordinate system, and the camera intrinsic reference results can be obtained using the Zhang Zhengyou calibration method.

[0069] Since the camera intrinsic parameter calibration device provided in the embodiment of the present application includes multiple calibration plates at different distances and different positions and postures, the camera's intrinsic parameters can be accurately calibrated by using an image taken by the camera including multiple calibration plates, which saves time, simplifies the process and improves efficiency.

[0070] In addition, the data file after the camera intrinsic calibration can also be stored in the intrinsic calibration data storage module. The file name can be in the form of a camera QR code to facilitate the management and query of the intrinsic calibration file.

[0071] The present application provides a camera intrinsic calibration method, which collects images of multiple calibration plates as described above, respectively establishes world coordinate systems for the multiple calibration plates, uses a corner point recognition algorithm to identify the corner points of the multiple calibration plates, matches the corner point coordinates with the world coordinates in the world coordinate system one by one, and then uses the Zhang Zhengyou calibration method to obtain the camera intrinsic parameter results. The process is simple, and when applied to the camera intrinsic calibration device loaded above, the camera intrinsic parameters can be quickly obtained, which improves efficiency, is easy to industrialize, and enhances the user experience.

[0072] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the method embodiment, since it is based on the device embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the device embodiment.

[0073] The above is only a preferred implementation of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of protection of the technical solution of the present application.

Claims

1. A camera intrinsic parameter calibration device, characterized in that: include: Internal reference calibration stand and multiple calibration plates; The plurality of calibration plates include: a first calibration plate, a second calibration plate, a third calibration plate, a fourth calibration plate, a fifth calibration plate, a sixth calibration plate, a seventh calibration plate and an eighth calibration plate; the plurality of calibration plates are arranged inside the internal reference calibration stand; The shape of the internal parameter calibration rig is a cuboid; the ratio of the width to the height of the internal parameter calibration rig is equal to the ratio of the horizontal field of view angle to the vertical field of view angle of the camera; The angle between the first calibration plate and the second calibration plate and the top surface of the calibration rack is 40°; the angle between the third calibration plate and the fourth calibration plate and the top surface of the calibration rack is 0°; the angle between the fifth calibration plate and the sixth calibration plate and the top surface of the calibration rack is 50°; the angle between the seventh calibration plate and the eighth calibration plate and the top surface of the calibration rack is 60°; The orthographic projections of the plurality of calibration plates on any side of the internal reference calibration stand are at least partially non-overlapping.

2. The device according to claim 1, characterized in that The device also includes: a camera fixing device; The camera fixing device is located on the outside of one side of the internal reference calibration platform, and the orthographic projection of the camera fixing device on the one side is at the intersection of the diagonal line of the one side.

3. The device according to claim 2, characterized in that The orthographic projections of the first calibration plate and the second calibration plate on one side of the internal reference calibration rig are the first projection; the orthographic projections of the third calibration plate and the fourth calibration plate on one side of the internal reference calibration rig are the second projection; the orthographic projections of the fifth calibration plate and the sixth calibration plate on one side of the internal reference calibration rig are the third projection; the orthographic projections of the seventh calibration plate and the eighth calibration plate on one side of the internal reference calibration rig are the fourth projection; The area of ​​the first projection that does not overlap with other projections accounts for 50% of the total projection area of ​​the multiple calibration plates; the area of ​​the second projection that does not overlap with other projections accounts for 16.6% of the total projection area of ​​the multiple calibration plates; the area of ​​the third projection that does not overlap with other projections accounts for 16.6% of the total projection area of ​​the multiple calibration plates; the area of ​​the fourth projection that does not overlap with other projections accounts for 16.6% of the total projection area of ​​the multiple calibration plates.

4. A camera intrinsic parameter calibration method, characterized in that: include: Acquiring images of a plurality of calibration plates as described in any one of claims 1 to 3; Establishing the world coordinate systems of the multiple calibration plates respectively; Using a corner point recognition algorithm to identify the corner points of each of the plurality of calibration plates; After matching the corner point coordinates of the corner points with the world coordinates in the world coordinate system one by one, the camera intrinsic parameter result is obtained by using Zhang Zhengyou calibration method.

5. The method according to claim 4, characterized in that The image is a grayscale image.

6. The method according to claim 5, characterized in that The corner point recognition algorithm includes: Harris algorithm.

7. The method according to any one of claims 4 to 6, characterized in that: The calibration plate is a checkerboard calibration plate; the corner point recognition algorithm is used to identify the corner points of each of the plurality of calibration plates, including: Locate the coordinate origin and the length of each checkerboard in the checkerboard calibration plate in the image; Using a corner point recognition algorithm to identify corner points in the image; The corner points in the image are sorted and screened; the screening includes: if the distance between the next corner point and the previous corner point exceeds the length of each chessboard in the image, then the next corner point is excluded; The corner points in the filtered image are used as the corner points of each of the multiple calibration plates.

8. The method according to claim 7, characterized in that The adopting a corner point recognition algorithm to recognize corner points in the image includes: A corner point recognition algorithm is used to recognize initial corner points in the image, and the initial corner points are refined to sub-pixels to obtain corner points in the image.

Images