A method, system, computer readable storage medium and computer program product for correcting shear deformation in line laser scanning three-dimensional reconstruction

Abstract

The present application relates to the technical fields of image processing and point cloud processing, and discloses a line laser scanning three-dimensional reconstruction shear deformation correction method, system, computer readable storage medium and computer program product, the method comprises the following steps: according to the ratio of the height measurement value and the height nominal value of the height block, the first direction deflection angle of the line laser scanning camera is calculated;And the included angle between the straight line L and the predetermined horizontal line is measured, and the second direction deflection angle of the line laser scanning camera is obtained;The third direction deflection angle of the line laser scanning camera is obtained by using the constraint relationship that the adjacent edges of the checkerboard grid are perpendicular to each other;The photographed image is sequentially deflected and corrected according to the order of the three direction deflection angles, and then outputted.The present application does not need camera internal and external parameters, greatly reduces the system calibration difficulty, improves the angle solving precision through the joint estimation of the height block and the checkerboard grid, has strong algorithm robustness, can effectively remove the three-dimensional shear deformation caused by splicing, and has high algorithm reconstruction precision.

Description

Technical Field

[0001] This invention relates to the fields of image processing and point cloud processing technology, and in particular to a method, system, computer-readable storage medium, and computer program product for correcting shear deformation in three-dimensional reconstruction using line laser scanning. Background Technology

[0002] Line laser scanning reconstruction technology is widely used in industrial measurement, robot navigation, and 3D inspection. In practical applications, because the direction of motion during scanning is not completely consistent with the direction of contour stitching, significant shear deformation can occur in the 3D reconstruction results.

[0003] Currently, the mainstream methods for movement vector calibration mainly include: (1) Independent estimation method: By moving the system and acquiring multiple images, the extrinsic parameters of each frame are estimated and the scanning direction is approximated. However, due to changes in image position and repeated calculation of extrinsic parameters, the error accumulates significantly and the stability is limited.

[0004] (2) Joint estimation method: The planar target is moved by a displacement stage at fixed steps, and the scanning direction is obtained by introducing a joint constraint of rotation matrix and translation vector. However, this method requires high accuracy of displacement stage and requires pre-calibration of camera intrinsic and extrinsic parameters, and has poor applicability.

[0005] Therefore, existing technologies generally have the following shortcomings: Offline calibration is complex, and the calibration method depends on the accuracy of the equipment (such as the displacement stage); it is highly dependent on the camera's intrinsic and extrinsic parameters, which limits its applicability; calculating extrinsic parameters from multiple images leads to an increase in instability factors.

[0006] In summary, there is an urgent need in this field for a three-dimensional reconstruction shear deformation correction method that is independent of camera intrinsic and extrinsic parameters, has a simplified calibration process, and is highly robust to errors. Summary of the Invention

[0007] The purpose of this invention is to provide a method, system, computer-readable storage medium, and computer program product for correcting shear deformation in three-dimensional reconstruction by line laser scanning, so as to solve or at least partially solve the technical problems mentioned in the background art.

[0008] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for correcting shear deformation in three-dimensional reconstruction using line laser scanning, comprising: Place the height block on the platform, and use a line laser scanning camera to illuminate the location of the height block with a laser to capture the outline of the light bar in that frame. The light stripe contour line is used to fit the straight line L on the bottom surface of the platform, and the height of the height block is measured. The first directional deflection angle of the line laser scanning camera is calculated based on the ratio of the measured height value of the height block to the nominal height value; and the second directional deflection angle of the line laser scanning camera is obtained by measuring the angle between the straight line L and the predetermined horizontal line. The corner points of the checkerboard in the sheared checkerboard image captured by the line laser scanning camera are converted to the corresponding undeformed checkerboard corner points according to the correction principle. Then, the third-direction deflection angle of the line laser scanning camera is obtained by using the constraint relationship that the adjacent sides of the checkerboard are perpendicular to each other. When a line laser scanning camera captures an image, the captured image is corrected for deflection in the order of third-direction deflection angle, second-direction deflection angle, and first-direction deflection angle before being output.

[0009] Optionally, the fitting method for the straight line L is as follows: use the RANSAC straight line fitting method to fit the center point of the light stripe illuminating the bottom surface of the platform.

[0010] Optionally, the height of the height block can be measured as follows: Calculate the average vertical distance from the center point of the light stripe on the top surface of the height block to the straight line L to obtain the height measurement value of the height block.

[0011] Optionally, the calculation method for the first direction deflection angle is as follows: Let the nominal height of the height block be H, and the measured height be H'. Then the first direction deflection angle θ x for: .

[0012] Optionally, the method for calculating the third-direction deflection angle is as follows: Let A(x1,y1), B(x2,y2), C(x3,y3), and D(x4,y4) be the four deformed corner points of a checkerboard grid in a checkerboard image captured by a line laser scanning camera, and let θ be the coordinates of the grid. y The second direction deflection angle, θ z The third-party deflection angle; the four deformed corner points, converted according to the correction principle, yield four undeformed corner points as follows: A': , B': , C': , D': ; Based on the fact that adjacent sides of a chessboard square are perpendicular, that is: ; The equation is constructed as follows: , , , ; Finally, sinθ is calculated using the quadratic formula. z The value of θ is taken as a valid value between [-1, 1], and then the arcsine function is used to find θ. z The value of .

[0013] Optionally, the method for sequentially correcting the deflection of the captured image according to the third direction deflection angle, the second direction deflection angle, and the first direction deflection angle before outputting the image is as follows: Let (x, d, z) be a point in the captured image. After obtaining the three deflection angles, according to θ z θ y θ x The deflection correction is performed sequentially, that is: After the first deflection correction, the coordinates are transformed into: , , ; After the second deflection correction, the coordinates are transformed into: , , ; After the third deflection correction, the coordinates are transformed into: , , ; Finally, the output for point (x, d, z) is: .

[0014] Optionally, before converting the corner points of the sheared and deformed checkerboard image captured by the line laser scanning camera to their corresponding undeformed corner points according to the correction principle, and then using the constraint relationship of the perpendicularity between adjacent edges of the checkerboard grid to obtain the third-direction deflection angle of the line laser scanning camera, the method further includes: The checkerboard calibration plate is placed flat on the platform, and the line laser scanning camera or the platform is moved to scan and acquire a 2D stitched image of the checkerboard calibration plate, thus obtaining the sheared and deformed checkerboard image.

[0015] Optionally, the light stripe contour line is a set of coordinate points of the light stripe center point, including the light stripe center point illuminating the bottom surface of the platform and the light stripe center point illuminating the top surface of the height block.

[0016] Secondly, the present invention provides a line laser scanning three-dimensional reconstruction correction system for shear deformation, comprising: A line laser scanning camera is used to illuminate the location of the height block placed on the platform with a laser and acquire the outline of the light stripe in that frame; and to capture a 2D stitched image of the checkerboard calibration board placed on the platform to obtain a sheared checkerboard image. The height measurement module is electrically connected to the line laser scanning camera and is used to fit the straight line L of the light stripe illuminating the bottom surface of the platform using the light stripe contour line, and to measure the height of the height block. The deflection angle calculation module is electrically connected to the height measurement module and is used to calculate the first direction deflection angle of the line laser scanning camera based on the ratio of the height measurement value of the height block to the nominal height value; and to measure the angle between the straight line L and the predetermined horizontal line to obtain the second direction deflection angle of the line laser scanning camera. The corner conversion module, which is electrically connected to the laser scanning camera, is used to convert the corner points of the chessboard in the sheared and deformed chessboard image to the corresponding undeformed chessboard corner points according to the correction principle. The deflection angle calculation module is also electrically connected to the corner conversion module, and is used to obtain the third-direction deflection angle of the line laser scanning camera by utilizing the constraint relationship that the adjacent sides of the chessboard grid are perpendicular to each other; The image output module is electrically connected to the deflection angle calculation module. It is used to perform deflection correction on the image captured by the line laser scanning camera in the order of third direction deflection angle, second direction deflection angle and first direction deflection angle before outputting it.

[0017] Optionally, the fitting method for the straight line L is as follows: use the RANSAC straight line fitting method to fit the center point of the light stripe illuminating the bottom surface of the platform.

[0018] Optionally, the height of the height block can be measured as follows: Calculate the average vertical distance from the center point of the light stripe on the top surface of the height block to the straight line L to obtain the height measurement value of the height block.

[0019] Optionally, the calculation method for the first direction deflection angle is as follows: Let the nominal height of the height block be H, and the measured height be H'. Then the first direction deflection angle θ x for: .

[0020] Optionally, the method for calculating the third-direction deflection angle is as follows: Let A(x1,y1), B(x2,y2), C(x3,y3), and D(x4,y4) be the four deformed corner points of a checkerboard grid in a checkerboard image captured by a line laser scanning camera, and let θ be the coordinates of the grid. y The second direction deflection angle, θ zThe third-party deflection angle; the four deformed corner points, converted according to the correction principle, yield four undeformed corner points as follows: A': , B': , C': , D': ; Based on the fact that adjacent sides of a chessboard square are perpendicular, that is: ; The equation is constructed as follows: , , , ; Finally, sinθ is calculated using the quadratic formula. z The value of θ is taken as a valid value between [-1, 1], and then the arcsine function is used to find θ. z The value of .

[0021] Optionally, the method for sequentially correcting the deflection of the captured image according to the third direction deflection angle, the second direction deflection angle, and the first direction deflection angle before outputting the image is as follows: Let (x, d, z) be a point in the captured image. After obtaining the three deflection angles, according to θ z θ y θ x The deflection correction is performed sequentially, that is: After the first deflection correction, the coordinates are transformed into: , , ; After the second deflection correction, the coordinates are transformed into: , , ; After the third deflection correction, the coordinates are transformed into: , , ; Finally, the output for point (x, d, z) is: .

[0022] Optionally, the method for acquiring the chessboard image is as follows: The checkerboard calibration plate is placed flat on the platform, and the line laser scanning camera or the platform is moved to scan and acquire a 2D stitched image of the checkerboard calibration plate, thus obtaining the sheared and deformed checkerboard image.

[0023] Optionally, the light stripe contour line is a set of coordinate points of the light stripe center point, including the light stripe center point illuminating the bottom surface of the platform and the light stripe center point illuminating the top surface of the height block.

[0024] Thirdly, the present invention provides a computer-readable storage medium storing at least one instruction, which is loaded and executed by a processor to implement a method for correcting shear deformation in three-dimensional reconstruction by line laser scanning as described above.

[0025] Fourthly, the present invention also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements a method for correcting shear deformation in three-dimensional reconstruction by line laser scanning as described above.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: The line laser scanning 3D reconstruction shear deformation correction method proposed in this application does not require camera intrinsic and extrinsic parameters, greatly reducing the difficulty of system calibration. It improves the accuracy of angle calculation by jointly estimating height blocks and checkerboard grids. The algorithm is robust and has a significant correction effect, which can effectively remove 3D shear deformation caused by stitching and improve the final reconstruction accuracy. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A flowchart illustrating a method for correcting shear deformation in three-dimensional reconstruction using line laser scanning, provided as an embodiment of the present invention.

[0029] Figure 2 The image shows a sheared checkerboard pattern captured by a line laser scanning camera, as provided in an embodiment of the present invention.

[0030] Figure 3 for Figure 2 The chessboard image is obtained by conversion according to the correction principle.

[0031] Figure 4 This is a schematic diagram illustrating the coordinate transformation principle for the first deflection correction provided in an embodiment of the present invention.

[0032] Figure 5 The diagram illustrates the coordinate transformation principle for the second deflection correction provided in this embodiment of the invention.

[0033] Figure 6 The diagram illustrates the coordinate transformation principle for the third deflection correction provided in this embodiment of the invention.

[0034] Figure 7 The image before and after correction is shown in the embodiment of the present invention.

[0035] Figure 8 This is a diagram illustrating the architecture of a line laser scanning three-dimensional reconstruction system for correcting shear deformation, provided as an embodiment of the present invention. Detailed Implementation

[0036] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] Example 1: Please refer to Figure 1 , Figure 1 A flowchart of a method for correcting shear deformation in three-dimensional reconstruction using line laser scanning, provided as an embodiment of the present invention, is shown below. The method includes: Step 100: Place the height block on the platform, use a line laser scanning camera to illuminate the location of the height block with a laser, and capture the outline of the light bar in that frame.

[0038] This step involves collecting calibration data. A line laser scanning camera is used to illuminate a standard height block, obtaining the outline of the light bar in that frame. This outline is used to measure the height of the height block. Due to the deflection angle, the height measurement under tilt will always be greater than the nominal value of the height block.

[0039] The outline of the light stripe here refers to the set of coordinate points of the center point of the light stripe, including the center point of the light stripe illuminating the bottom surface of the platform and the center point of the light stripe illuminating the top surface of the height block.

[0040] Step 110: Fit the straight line L of the light stripe illuminating the bottom surface of the platform using the light stripe contour line, and measure the height of the height block.

[0041] In this step, the fitting method for the straight line L is as follows: the RANSAC straight line fitting method is used to fit the center point of the light stripe illuminating the bottom surface of the platform. Specifically, let the point cloud coordinates of a set of light stripe contour lines be represented as (xi ,0,z i ), which can be represented on the laser plane as (x i ,z i The RANSAC line fitting method was used to fit the set of points to obtain the straight line L that illuminates the bottom surface of the platform. Since the RANSAC line fitting method is an existing technology, its fitting principle and process will not be described in detail here.

[0042] Let H' be the measured height (height measurement value) of the height block with a nominal height of H, where H' is the average distance from the center point of the light strip on the height block to the straight line L.

[0043] Step 120: Calculate the first directional deflection angle of the line laser scanning camera based on the ratio of the measured height value of the height block to the nominal height value; and measure the angle between the straight line L and the predetermined horizontal line to obtain the second directional deflection angle of the line laser scanning camera.

[0044] Let the first yaw angle (pitch angle) be θ. x The second directional deflection angle (roll angle) is θ. y ,but: ; θ is obtained by measuring the angle between the straight line L and the horizontal line. y .

[0045] Step 130: Convert the corner points of the checkerboard in the sheared checkerboard image captured by the line laser scanning camera to the corresponding undeformed checkerboard corner points according to the correction principle, and then use the constraint relationship that the adjacent sides of the checkerboard are perpendicular to each other to obtain the third-direction deflection angle of the line laser scanning camera.

[0046] Let the third-direction yaw angle be θ. z In calculating θ z Previously, another set of calibration data needed to be collected, namely, by performing: Step 101: Place the checkerboard calibration plate flat on the platform, drive the line laser scanning camera to move or move the platform to scan and obtain a 2D stitched image of the checkerboard calibration plate, and obtain a sheared and deformed checkerboard image.

[0047] θ z The calculation method is as follows: like Figure 2 As shown, let A(x1,y1), B(x2,y2), C(x3,y3), and D(x4,y4) be the four deformed corner points of a chessboard grid in the chessboard image obtained in step 101, respectively. The four undeformed corner points obtained by converting these four deformed corner points according to the correction principle are as follows: Figure 3 As shown, that is: A': , B': , C': , D': .

[0048] The constraint is that adjacent sides of a chessboard square are perpendicular. ; Therefore, the equation can be constructed as follows: , , , .

[0049] Finally, sinθ is calculated using the quadratic formula. z The value of θ is taken as a valid value between [-1, 1], and then the arcsine function is used to find θ. z The value of .

[0050] Step 140: When the line laser scanning camera captures an image, the captured image is deflected in sequence according to the third direction deflection angle, the second direction deflection angle, and the first direction deflection angle before being output.

[0051] For example, such as Figure 4 As shown, let (x, d, z) be a point in the captured image. After obtaining the three deflection angles, according to θ z θ y θ x The deflection correction is performed sequentially, that is: After the first deflection correction, the coordinates are transformed into: , , ; like Figure 5 As shown, after the second deflection correction, the coordinates are transformed into: , , ; like Figure 6 As shown, after the third deflection correction, the coordinates are transformed into: , , ; After three corrections, shear deformation can be eliminated, and the output for point (x,d,z) is: .

[0052] To verify the practical application performance of the line laser scanning three-dimensional reconstruction shear deformation correction method provided in this embodiment, specific application examples are given below.

[0053] First, acquire an image of the chessboard calibration board ( Figure 7 (Top left image) and the outline data of the block with a nominal height of H=30mm; Using RANSAC fitting, the bottom light stripe line L is obtained. The angle between this line and the horizontal line is found to be 2.2976 degrees. Therefore: θ y =2.2976; Next, the average distance H' from the center point of the light stripe on the height block to the fitted straight line L is calculated in the contour data to be 31.8367 mm. Therefore, ; To reduce random errors, in calculating θ z The value is the average of all grid results on the calibration board. Below is one set of data: A (2189.9, 3261.1), B (1937.4, 3197.1), C (1683.8, 3132.8), and D (1431.0, 3069.6).

[0054] Combine the coordinate values ​​and the calculated deflection angle θ x θ y Substitute the information from step 130 about In the quadratic equation in one variable, that is: ; Solving for: = -0.1685, -34.0945 (discarded); therefore = -9.7003; The average value of the calculated results for all chessboard corner points is: -9.5275842524320229. Finally, take θ z It is -9.5276.

[0055] The shear deformation correction effect is shown in the attached figure. Figure 7 As shown. Figure 7 The two images on the top are the checkerboard calibration board before and after calibration, respectively. Figure 7 The two images below are real-world images taken by the camera before and after correction; in the accuracy test, the average absolute value of the difference between the included angle of adjacent sides of the chessboard and 90 degrees after correction was 0.03 degrees, and the average value of the angle blocks after correction was 0.05 degrees.

[0056] In summary, compared with the prior art, the present invention has at least the following advantages: (1) No camera internal / external parameters are required, greatly reducing the difficulty of system calibration.

[0057] (2) Data acquisition is simple and has few limitations on the device, and no fixed step length or high-precision displacement stage is required.

[0058] (3) The algorithm is robust and improves the accuracy of angle calculation by jointly estimating the height block and the chessboard grid.

[0059] (4) The correction effect is significant, which can effectively remove the three-dimensional shear deformation caused by splicing and improve the final reconstruction accuracy.

[0060] Example 2: Please refer to Figure 8 , Figure 8 A system architecture diagram for correcting shear deformation by line laser scanning three-dimensional reconstruction is provided in this embodiment of the invention. The system includes: A line laser scanning camera 10 is used to irradiate the position of the height block placed on the platform with a laser and acquire the outline of the light stripe in that frame; and to capture a 2D stitched image of the checkerboard calibration board placed on the platform to obtain a sheared checkerboard image; wherein the outline of the light stripe is a set of coordinate points of the center point of the light stripe, including the center point of the light stripe irradiating the bottom surface of the platform and the center point of the light stripe irradiating the top surface of the height block; The height measurement module 20 and the electrically connected laser scanning camera 10 are used to fit the straight line L of the light stripe illuminating the bottom surface of the platform using the light stripe contour line and to measure the height of the height block. The deflection angle calculation module 30 and the height measurement module 20 are electrically connected to calculate the first direction deflection angle of the line laser scanning camera based on the ratio of the height measurement value of the height block to the nominal height value; and measure the angle between the straight line L and the predetermined horizontal line to obtain the second direction deflection angle of the line laser scanning camera. Corner conversion module 40 and electrical connection laser scanning camera 10 are used to convert the corner points of the chessboard in the sheared and deformed chessboard image to the corresponding undeformed chessboard corner points according to the correction principle. The deflection angle calculation module 30 is also electrically connected to the corner point conversion module 40, which is used to obtain the third-direction deflection angle of the line laser scanning camera by utilizing the constraint relationship that the adjacent sides of the chessboard grid are perpendicular to each other. The image output module 50 is electrically connected to the deflection angle calculation module 30, which is used to perform deflection correction on the image captured by the line laser scanning camera 10 in the order of third direction deflection angle, second direction deflection angle and first direction deflection angle before outputting it.

[0061] The specific method for acquiring the checkerboard image is as follows: the checkerboard calibration plate is placed flat on the platform, and the line laser scanning camera or the platform is moved to scan and acquire the 2D stitched image of the checkerboard calibration plate, thus obtaining the sheared and deformed checkerboard image.

[0062] The above-described device can realize the line laser scanning three-dimensional reconstruction shear deformation correction method described in Embodiment 1. Since Embodiment 1 has already described the line laser scanning three-dimensional reconstruction shear deformation correction method in detail, it will not be repeated in this embodiment.

[0063] Example 3: This embodiment also provides a computer-readable storage medium storing at least one instruction, which is loaded and executed by a processor to implement a method for correcting shear deformation in three-dimensional reconstruction using line laser scanning as described in Embodiment 1.

[0064] Since Example 1 has already described in detail the method for correcting shear deformation in three-dimensional reconstruction by line laser scanning, it will not be repeated in this example.

[0065] Example 4: The present invention also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements a method for correcting shear deformation in three-dimensional reconstruction by line laser scanning as described in Embodiment 1.

[0066] Since Example 1 has already described in detail the method for correcting shear deformation in three-dimensional reconstruction by line laser scanning, it will not be repeated in this example.

[0067] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware, or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0068] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0069] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for correcting shear deformation in three-dimensional reconstruction using line laser scanning, characterized in that, include: Place the height block on the platform, and use a line laser scanning camera to illuminate the location of the height block with a laser to capture the outline of the light bar in that frame. The light stripe contour line is used to fit the straight line L on the bottom surface of the platform, and the height of the height block is measured. The first directional deflection angle of the line laser scanning camera is calculated based on the ratio of the measured height value of the height block to the nominal height value; and the second directional deflection angle of the line laser scanning camera is obtained by measuring the angle between the straight line L and the predetermined horizontal line. The corner points of the checkerboard in the sheared checkerboard image captured by the line laser scanning camera are converted to the corresponding undeformed checkerboard corner points according to the correction principle. Then, the third-direction deflection angle of the line laser scanning camera is obtained by using the constraint relationship that the adjacent sides of the checkerboard are perpendicular to each other. When a line laser scanning camera captures an image, the captured image is corrected for deflection in the order of third-direction deflection angle, second-direction deflection angle, and first-direction deflection angle before being output.

2. The method for correcting shear deformation in three-dimensional reconstruction using line laser scanning according to claim 1, characterized in that, The specific fitting method for line L is as follows: use the RANSAC line fitting method to fit the center point of the light stripe illuminating the bottom surface of the platform.

3. The method for correcting shear deformation in three-dimensional reconstruction using line laser scanning according to claim 2, characterized in that, The method for measuring the height of the height block is as follows: Calculate the average vertical distance from the center point of the light stripe on the top surface of the height block to the straight line L to obtain the height measurement value of the height block.

4. The method for correcting shear deformation in three-dimensional reconstruction using line laser scanning according to claim 3, characterized in that, The calculation method for the first directional deflection angle is as follows: Let the nominal height of the height block be H, and the measured height be H'. Then the first direction deflection angle θ x for: 。 5. The method for correcting shear deformation in three-dimensional reconstruction using line laser scanning according to claim 4, characterized in that, The method for calculating the third-direction deflection angle is as follows: Let A(x1,y1), B(x2,y2), C(x3,y3), and D(x4,y4) be the four deformed corner points of a checkerboard grid in a checkerboard image captured by a line laser scanning camera, and let θ be the coordinates of the grid. y The second direction deflection angle, θ z The third-party deflection angle; the four deformed corner points, converted according to the correction principle, yield four undeformed corner points as follows: A’： ， B’： ， C’： ， D’： ； Based on the fact that adjacent sides of a chessboard square are perpendicular, that is: ； The equation is constructed as follows: ， ， ， ； Finally, sinθ is calculated using the quadratic formula. z The value of θ is taken as a valid value between [-1, 1], and then the arcsine function is used to find θ. z The value of .

6. The method for correcting shear deformation in three-dimensional reconstruction using line laser scanning according to claim 5, characterized in that, The method involves sequentially correcting the deflection of the captured image according to the third direction deflection angle, the second direction deflection angle, and the first direction deflection angle before outputting it. Let (x, d, z) be a point in the captured image. After obtaining the three deflection angles, according to θ z θ y θ x The deflection correction is performed sequentially, that is: After the first deflection correction, the coordinates are transformed into: ， ， ； After the second deflection correction, the coordinates are transformed into: ， ， ； After the third deflection correction, the coordinates are transformed into: ， ， ； final The output for point (x, d, z) is: .

7. The method for correcting shear deformation in three-dimensional reconstruction using line laser scanning according to claim 1, characterized in that, Before converting the corner points of the sheared checkerboard image captured by the line laser scanning camera to their corresponding undeformed corner points according to the correction principle, and then calculating the third-direction deflection angle of the line laser scanning camera using the constraint relationship that adjacent edges of the checkerboard are perpendicular, the process further includes: The checkerboard calibration plate is placed flat on the platform, and the line laser scanning camera or the platform is moved to scan and acquire a 2D stitched image of the checkerboard calibration plate, thus obtaining the sheared and deformed checkerboard image.

8. The method for correcting shear deformation in three-dimensional reconstruction using line laser scanning according to claim 1, characterized in that, The light stripe outline is a set of coordinate points of the light stripe center point, including the light stripe center point illuminating the bottom surface of the platform and the light stripe center point illuminating the top surface of the height block.

9. A line laser scanning three-dimensional reconstruction correction system for shear deformation, characterized in that, include: A line laser scanning camera is used to illuminate the location of a height block placed on a platform with a laser and capture the outline of the light bar in that frame. And, to capture 2D stitched images of a checkerboard calibration board placed on a platform to obtain a cut-and-distorted checkerboard image; The height measurement module is electrically connected to the line laser scanning camera and is used to fit the straight line L of the light stripe illuminating the bottom surface of the platform using the light stripe contour line, and to measure the height of the height block. The deflection angle calculation module is electrically connected to the height measurement module and is used to calculate the first direction deflection angle of the line laser scanning camera based on the ratio of the height measurement value of the height block to the nominal height value; and to measure the angle between the straight line L and the predetermined horizontal line to obtain the second direction deflection angle of the line laser scanning camera. Corner conversion module, electrically connected to laser scanning camera, used to convert the corner points of the chessboard in the sheared and deformed chessboard image to the corresponding undeformed chessboard corner points according to the correction principle; The deflection angle calculation module is also electrically connected to the corner conversion module, and is used to obtain the third-direction deflection angle of the line laser scanning camera by utilizing the constraint relationship that the adjacent sides of the chessboard grid are perpendicular to each other; The image output module is electrically connected to the deflection angle calculation module. It is used to perform deflection correction on the image captured by the line laser scanning camera in the order of third direction deflection angle, second direction deflection angle and first direction deflection angle before outputting it.

10. A line laser scanning three-dimensional reconstruction shear deformation correction system according to claim 9, characterized in that, The specific fitting method for line L is as follows: use the RANSAC line fitting method to fit the center point of the light stripe illuminating the bottom surface of the platform.

11. The line laser scanning three-dimensional reconstruction shear deformation correction system according to claim 10, characterized in that, The method for measuring the height of the height block is as follows: Calculate the average vertical distance from the center point of the light stripe on the top surface of the height block to the straight line L to obtain the height measurement value of the height block.

12. The line laser scanning three-dimensional reconstruction shear deformation correction system according to claim 11, characterized in that, The calculation method for the first directional deflection angle is as follows: Let the nominal height of the height block be H, and the measured height be H'. Then the first direction deflection angle θ x for: 。 13. The line laser scanning three-dimensional reconstruction shear deformation correction system according to claim 12, characterized in that, The method for calculating the third-direction deflection angle is as follows: Let A(x1,y1), B(x2,y2), C(x3,y3), and D(x4,y4) be the four deformed corner points of a checkerboard grid in a checkerboard image captured by a line laser scanning camera, and let θ be the coordinates of the grid. y The second direction deflection angle, θ z The third-party deflection angle; the four deformed corner points, converted according to the correction principle, yield four undeformed corner points as follows: A’： ， B’： ， C’： ， D’： ； Based on the fact that adjacent sides of a chessboard square are perpendicular, that is: ； The equation is constructed as follows: ， ， ， ； Finally, sinθ is calculated using the quadratic formula. z The value of θ is taken as a valid value between [-1, 1], and then the arcsine function is used to find θ. z The value of .

14. The line laser scanning three-dimensional reconstruction shear deformation correction system according to claim 13, characterized in that, The method involves sequentially correcting the deflection of the captured image according to the third direction deflection angle, the second direction deflection angle, and the first direction deflection angle before outputting it. Let (x, d, z) be a point in the captured image. After obtaining the three deflection angles, according to θ z θ y θ x The deflection correction is performed sequentially, that is: After the first deflection correction, the coordinates are transformed into: ， ， ； After the second deflection correction, the coordinates are transformed into: ， ， ； After the third deflection correction, the coordinates are transformed into: ， ， ； final The output for point (x, d, z) is: .

15. A line laser scanning three-dimensional reconstruction shear deformation correction system according to claim 9, characterized in that, The specific method for acquiring the chessboard image is as follows: The checkerboard calibration plate is placed flat on the platform, and the line laser scanning camera or the platform is moved to scan and acquire a 2D stitched image of the checkerboard calibration plate, thus obtaining the sheared and deformed checkerboard image.

16. The line laser scanning three-dimensional reconstruction shear deformation correction system according to claim 9, characterized in that, The light stripe outline is a set of coordinate points of the light stripe center point, including the light stripe center point illuminating the bottom surface of the platform and the light stripe center point illuminating the top surface of the height block.

17. A computer-readable storage medium storing at least one instruction, characterized in that, The instructions are loaded and executed by the processor to implement a method for correcting shear deformation in three-dimensional reconstruction by line laser scanning as described in any one of claims 1-8.

18. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the method for correcting shear deformation in three-dimensional reconstruction by line laser scanning as described in any one of claims 1-8.

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