A structured light three-dimensional vertical line measurement device and method

Abstract

The present invention proposes a structured light three-dimensional vertical line measurement device and method. The method of the present invention calibrates the CCD camera parameters by Zhang Zhengyou camera calibration method; calibrates the laser plane parameters by line structured light calibration method based on chessboard; calculates the calibration parameters of the vertical line direction vector by placing two chessboards in vertical postures; the computer controls the CCD camera to collect panoramic images, extracts the image coordinates of the light point where the laser plane in the horizontal direction intersects the vertical line and the center point of the ball, and constructs the analytical equation of the vertical line and the light equation of the projection imaging of the center point of the ball in combination with the calibration parameters, and solves them together to obtain the coordinates of the center point of the ball. The change in the coordinates of the center point of the ball is the displacement of the vertical line in the three directions of X, Y, and Z. The advantages of the present invention are that there is no need to configure three sets of light sources and sensors of the same structure in three directions, simplifying the structure and improving stability; using high-resolution cameras and lenses, making full use of the field of view, and improving measurement accuracy and measurement range.

Description

Technical Field

[0001] The method of the invention belongs to the field of computer vision, and in particular relates to a structured light three-dimensional vertical line measurement device and method. Background Art

[0002] The plumb line coordinate measuring machine is a traditional instrument for measuring the horizontal displacement and (vertical displacement) of large engineering structures. It is widely used for monitoring the horizontal displacement and deflection of dams and buildings. It is an important instrument to ensure the safe operation of dams. In order to achieve the goals of real-time acquisition, accurate and reliable, online monitoring and rapid feedback of plumb line instrument observation data, it is required to adopt an automated measurement method. With the development of sensor technology, the use of automatic telemetry to replace the traditional manual observation mode has become an important development direction for safety monitoring.

[0003] According to the working principle, the vertical coordinate meter can be divided into capacitive, eddy current, photoelectric and other types. The traditional capacitive vertical coordinate meter can realize the large-scale, high-sensitivity and high-precision measurement of the vertical line, but when the measurement environment is humid and dusty, the dielectric constant between the capacitor plates is prone to slow changes, resulting in distorted measurement results. CCD sensors are widely used in vertical coordinate meters due to their small size, light weight, high integration, low power consumption, good linearity, large dynamic range, long life and strong anti-interference ability. Most of the existing automatic vertical coordinate meters use displacement measurement technology based on linear array CCD sensors. Design method of vertical coordinate meter based on CCD A vertical coordinate meter based on linear array CCD was developed for mine wall deformation observation. Development method of new photoelectric vertical coordinate meter A large-scale lensless CCD vertical coordinate meter was developed. However, there are still problems such as only being able to measure two directions of the plane, repeated measuring devices, small range, and measurement accuracy affected by the quality of parallel light sources. On this basis, the design method of the three-dimensional vertical coordinate instrument based on CCD fixes a disk perpendicular to the vertical reference line in the horizontal direction as the vertical reference in the vertical direction, and designs a three-dimensional vertical coordinate instrument. In order to expand the measurement range of the vertical coordinate instrument, the development method of the large-scale stepping vertical coordinate instrument adopts the stepping measurement principle. The stepping motor drives the photoelectric probe to realize the plane two-dimensional displacement measurement and the laser emission and reception are used for position detection. The driving pulses of the stepping motor are counted, and the movement distance is calculated by the lead screw to give the displacement value. The high-speed and high-precision vertical coordinate instrument adopts a similar idea to develop a high-speed and high-precision vertical coordinate instrument. The instrument uses a grating ruler for displacement measurement. The vertical coordinate instrument based on the stepping measurement principle has a complex structure and high cost because it contains a motor and a lead screw mechanism. Summary of the invention

[0004] In view of the problems of the prior art, the present invention proposes a structured light three-dimensional vertical line measurement device and method. The present invention does not rely on a high-precision parallel light source and a motor screw mechanism, has a simple structure, good real-time performance, and strong adaptability to different environments.

[0005] The technical solution of the device of the present invention is a structured light three-dimensional vertical line measuring device, comprising: a computer, a CCD camera, a line laser transmitter, a vertical line to be measured, a bracket, and a small ball;

[0006] The CCD camera is connected to the computer;

[0007] The line laser transmitter is placed below the CCD camera, facing the vertical line to be measured, and transmits a horizontal laser plane;

[0008] The small ball is fixed on the vertical line to be measured, and the vertical line to be measured is suspended in front of the CCD camera through the bracket;

[0009] The technical solution of the method of the present invention is a structured light three-dimensional vertical line measurement method, comprising the following steps:

[0010] Step 1: The computer calibrates the principal point, focal length and distortion parameters of the CCD camera through the Zhang Zhengyou camera calibration method to obtain the principal point, focal length and distortion parameters of the calibrated camera;

[0011] Step 2: The computer calibrates the laser plane parameters by a line structure calibration method based on a chessboard to obtain the laser plane equation parameters;

[0012] Step 3: Place the chessboard vertically in front of the CCD camera, and the computer uses the CCD camera to collect the first-pose chessboard image, extract the first-pose image coordinates of the chessboard corner points and the first-pose world coordinates in the local chessboard world coordinate system, calculate the first pose of the local chessboard world coordinate system, calculate the first-pose camera coordinates of the chessboard corner points in the camera coordinate system, and calculate the first-pose camera coordinates of the chessboard corner points in the camera coordinate system by the least squares fitting method to obtain the normal vector of the first-pose chessboard plane;

[0013] Step 4: After rotating the chessboard by a certain angle, the computer collects the second posture chessboard image through the CCD camera, extracts the second posture image coordinates of the chessboard corner points and the second posture world coordinates in the local chessboard world coordinate system, calculates the second posture camera coordinates of the chessboard corner points in the camera coordinate system, and calculates the second posture camera coordinates of the chessboard corner points in the camera coordinate system by the least squares fitting method to obtain the normal vector of the second posture chessboard plane;

[0014] Step 5: Perform a cross product of the normal vector of the first posture chessboard plane and the normal vector of the second posture chessboard plane to obtain a vertical direction vector calibration parameter;

[0015] Step 6: The computer controls the CCD camera to collect the panoramic image, and the panoramic image is distorted and corrected in combination with the CCD camera distortion parameters to obtain the distortion-corrected image. The image coordinates of the light point where the horizontal laser plane intersects the vertical line are extracted, and the image coordinates of the center point of the ball are extracted. The analytical equation of the vertical line and the light equation of the projection imaging of the center point of the ball are constructed, and the displacement of the vertical line in the three directions of X, Y, and Z is obtained by solving the equation.

[0016] Preferably, the first posture image coordinates of the checkerboard corner points and the first posture world coordinates in the local checkerboard world coordinate system are extracted in step 3, specifically:

[0017] The computer processes the first posture checkerboard image using a checkerboard corner point extraction algorithm to extract the first posture image coordinates of the checkerboard corner points and the first posture world coordinates in a local checkerboard world coordinate system;

[0018] Preferably, the first posture of the local chessboard world coordinate system is calculated in step 3, specifically:

[0019] The computer uses a PnP algorithm to combine the first posture image coordinates of the checkerboard corner point and the first posture world coordinates of the checkerboard corner point in the local checkerboard world coordinate system to calculate the first posture of the local checkerboard world coordinate system;

[0020] Preferably, the first posture camera coordinates of the chessboard corner points in the camera coordinate system are calculated in step 3, specifically:

[0021] Combining the calibrated camera principal point, the calibrated camera focal length, the calibrated camera distortion parameters, and the first pose of the local chessboard world coordinate system, the first pose camera coordinates of the chessboard corner points in the camera coordinate system are calculated through the camera imaging model;

[0022] Preferably, the second posture image coordinates of the checkerboard corner points and the second posture world coordinates in the local checkerboard world coordinate system are extracted in step 4, specifically as follows:

[0023] The computer processes the second posture checkerboard image using a checkerboard corner point extraction algorithm to extract the second posture image coordinates of the checkerboard corner points and the second posture world coordinates in a local checkerboard world coordinate system;

[0024] Preferably, the second pose of the local chessboard world coordinate system is calculated in step 4 as follows:

[0025] The computer uses a PnP algorithm to combine the second posture image coordinates of the checkerboard corner points and the second posture world coordinates of the checkerboard corner points in the local checkerboard world coordinate system to calculate the second posture of the local checkerboard world coordinate system;

[0026] Preferably, the second posture camera coordinates of the checkerboard corner points in the camera coordinate system are calculated in step 4, specifically:

[0027] Combining the calibrated camera principal point, the calibrated camera focal length, the calibrated camera distortion parameters, and the second pose of the local chessboard world coordinate system, the second pose camera coordinates of the chessboard corner points in the camera coordinate system are calculated through the camera imaging model;

[0028] Preferably, the image coordinates of the light point where the horizontal laser plane intersects the vertical line in step 6 are specifically:

[0029] The image after distortion correction is processed by extracting the image coordinates of the light point where the horizontal laser plane intersects the vertical line through median filtering, binarization, and grayscale centroid method;

[0030] Preferably, the image coordinates of the center point of the ball are extracted in step 6, specifically:

[0031] The computer uses morphological filtering and connected domain analysis to extract the image block containing the ball after distortion correction, and uses Gaussian filtering, canny edge extraction, and ellipse fitting to extract the image coordinates of the center point of the ball.

[0032] Preferably, the analytical equation for constructing the vertical line in step 6 is specifically:

[0033] The computer combines the laser plane equation parameters, solves the coordinates of the light spot through the principle of laser triangulation, and constructs the analytical equation of the vertical line by combining the vertical line direction vector calibration parameters;

[0034] Preferably, the light equation for constructing the projection imaging of the center point of the ball in step 6 is specifically:

[0035] The computer combines the calibrated camera principal point, the calibrated camera focal length, and the calibrated camera distortion parameters, and constructs the light equation of the projection imaging of the center point of the ball according to the camera imaging model;

[0036] Preferably, the displacement of the vertical line in the three directions of X, Y and Z is obtained by solving step 6, specifically:

[0037] The computer combines the analytical equation of the perpendicular line and the light equation of the projection image of the center point of the ball to solve the coordinates of the center point of the ball. The change in the coordinates of the center point of the ball is the displacement of the perpendicular line in the X, Y, and Z directions.

[0038] The advantages of the present invention are that it is based on the laser triangulation ranging principle of line structured light and adopts a single line structured light source, so that three-dimensional displacement measurement of the vertical line can be realized, and there is no need to configure three sets of light sources and sensors with the same structure in the X, Y and Z directions respectively, which simplifies the structure and improves the stability; by using a high-resolution camera and lens and making full use of the field of view, the measurement accuracy and measurement range can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 : Schematic diagram of the device structure of an embodiment of the present invention.

[0040] Figure 2 : Flow chart of the method of an embodiment of the present invention.

[0041] Figure 3 : Schematic diagram of the principle of calibrating the vertical line direction vector in three-dimensional vertical line measurement according to an embodiment of the present invention.

[0042] Figure 4 : Schematic diagram of the three-dimensional vertical line measurement principle of an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In specific implementation, the method proposed in the technical solution of the present invention can be implemented by technical personnel in this field using computer software technology to realize automatic operation process. System devices for implementing the method, such as computer-readable storage media storing the corresponding computer program of the technical solution of the present invention and computer equipment running the corresponding computer program, should also be within the scope of protection of the present invention.

[0045] Figure 1 Schematic diagram of the structure of the device of the embodiment of the present invention. The technical solution of the device of the embodiment of the present invention is a structured light three-dimensional vertical line measurement device, including: a computer, a CCD camera, a line laser transmitter, a vertical line to be measured, a bracket, and a small ball;

[0046] The CCD camera is connected to the computer;

[0047] The line laser transmitter is placed below the CCD camera, facing the vertical line to be measured, and transmits a horizontal laser plane;

[0048] The small ball is fixed on the vertical line to be measured, and the vertical line to be measured is suspended in front of the CCD camera through the bracket.

[0049] The computer is selected as follows: i7-7700 CPU, 16GB memory, Windows 10 operating system;

[0050] The CCD camera is selected as: JAI GO-5000M-PGE;

[0051] The line laser transmitter is selected as: Hengjiu-100M-16A648-50-GLXS;

[0052] The selection of the vertical line to be measured is: white building chord;

[0053] The selection of the bracket is: a laboratory bracket with a height of 50 cm;

[0054] The small balls are white plastic hollow small balls with a diameter of 5 mm.

[0055] Combine the following Figure 2-Figure 4 A structured light three-dimensional vertical line measurement method provided by an embodiment of the present invention is introduced as follows:

[0056] Step 1: The computer calibrates the principal point, focal length and distortion parameters of the CCD camera through the Zhang Zhengyou camera calibration method to obtain the principal point, focal length and distortion parameters of the calibrated camera;

[0057] Step 2: The computer calibrates the laser plane parameters by a line structure calibration method based on a chessboard to obtain the laser plane equation parameters;

[0058] Step 3: Place the chessboard vertically in front of the CCD camera, and the computer collects the first posture chessboard image through the CCD camera. The computer uses the chessboard corner point extraction algorithm to process the first posture chessboard image, and extracts the first posture image coordinates of the chessboard corner points and the first posture world coordinates in the local chessboard world coordinate system; the computer uses the PnP algorithm to combine the first posture image coordinates of the chessboard corner points and the first posture world coordinates of the chessboard corner points in the local chessboard world coordinate system to calculate the first posture of the local chessboard world coordinate system; combine the calibrated camera principal point, the calibrated camera focal length, the calibrated camera distortion parameters, and the first position of the local chessboard world coordinate system, calculate the first posture camera coordinates of the chessboard corner points in the camera coordinate system through the camera imaging model, and calculate the first posture camera coordinates of the chessboard corner points in the camera coordinate system through the least squares fitting method to obtain the normal vector of the first posture chessboard plane;

[0059] Step 4: After rotating the chessboard by a certain angle, the computer collects the second posture chessboard image through the CCD camera, and the computer processes the second posture chessboard image using the chessboard corner point extraction algorithm to extract the second posture image coordinates of the chessboard corner points and the second posture world coordinates in the local chessboard world coordinate system; the computer uses the PnP algorithm to combine the second posture image coordinates of the chessboard corner points and the second posture world coordinates of the chessboard corner points in the local chessboard world coordinate system to calculate the second posture of the local chessboard world coordinate system; the camera imaging model is used to calculate the second posture camera coordinates of the chessboard corner points in the camera coordinate system by combining the calibrated camera principal point, the calibrated camera focal length, the calibrated camera distortion parameters, and the second posture of the local chessboard world coordinate system, and the second posture camera coordinates of the chessboard corner points in the camera coordinate system are calculated by the least squares fitting method to obtain the normal vector of the second posture chessboard plane;

[0060] Step 5: Perform a cross product of the normal vector of the first posture chessboard plane and the normal vector of the second posture chessboard plane to obtain a vertical direction vector calibration parameter;

[0061] Step 6: The computer controls the CCD camera to collect the panoramic image, and performs distortion correction on the panoramic image in combination with the CCD camera distortion parameters to obtain the distortion-corrected image; the image after distortion correction is processed, and the image coordinates of the light point where the laser plane intersects the vertical line in the horizontal direction are extracted by median filtering, binarization, and grayscale centroid method; the computer intercepts the image block containing the small ball through morphological filtering and connected domain analysis of the distortion-corrected image, and extracts the image coordinates of the center point of the small ball through Gaussian filtering, canny edge extraction, and ellipse fitting of the image block containing the small ball; the computer combines the laser plane equation parameters, solves the coordinates of the light point through the principle of laser triangulation, and constructs the analytical equation of the vertical line in combination with the calibration parameters of the vertical direction vector; the computer combines the calibrated camera principal point, the calibrated camera focal length, and the calibrated camera distortion parameters, and constructs the light equation of the projection imaging of the center point of the small ball according to the camera imaging model; the computer combines the analytical equation of the vertical line and the light equation of the projection imaging of the center point of the small ball to solve the coordinates of the center point of the small ball, and the change in the coordinates of the center point of the small ball is the displacement of the vertical line in the three directions of X, Y, and Z.

[0062] The principle of calibrating the vertical line direction vector of the three-dimensional vertical line measurement of the embodiment of the present invention is as follows Figure 3 As shown, O-uv is the camera imaging surface, O c -X c Y c Z c is the camera coordinate system. The chessboard plane α 1 is the checkerboard plane in the first posture, the checkerboard plane α 2 is the chessboard plane in the second posture. c，i，jis the chessboard plane α 1 The coordinates of the previous corner point in the camera coordinate system, where the subscript c indicates that the coordinate value is based on the camera coordinate system, the subscript i indicates that the corner point is located in the i-th row of the chessboard, and the subscript j indicates that the corner point is located in the j-th column of the chessboard. Based on the size of the calibration board used, which is 11×8, the value range of the subscript i is 1 to 11, and the value range of the subscript j is 1 to 8. w，i，j is the coordinate of the corner point of the i-th row and j-th column in the local chessboard world coordinate system, where the subscript w indicates that the coordinate value is based on the local chessboard world coordinate system. i，j is the image coordinates of the projection point of the chessboard corner point in the i-th row and j-th column. 1 is the chessboard plane α 1 The normal vector, n 2 is the chessboard plane α 2 The normal vector of the plane α is n, and the vertical line is the normal vector calibration parameter. 1 With plane α 2 The vertical direction vector can be obtained by cross product of the normal vectors of the two planes, that is, n = n 1 ×n 2 .

[0063] The three-dimensional vertical line measurement principle of the embodiment of the present invention is as follows Figure 4 As shown, O-uv is the camera imaging surface, O c -X c Y c Z c is the camera coordinate system. c is the center point of the ball, and p is the image point of its image. 1 is the point where the laser plane intersects the vertical line, p 1 The image point of the image. The light P projected by the center point of the ball c p intersects the perpendicular line at point P c , then the combined light P c The equation of p and the equation of the perpendicular line are:

[0064]

[0065] Among them, f x is the focal length of the camera in the X direction after calibration, f y is the camera focal length in the Y direction after calibration, u 0 is the X-direction offset of the camera principal point after calibration, v 0 is the Y-direction offset of the camera principal point after calibration, n x The X-direction component of the vertical direction vector calibration parameter n, n y The Y direction component of the vertical direction vector calibration parameter n, n z is the Z-direction component of the vertical direction vector calibration parameter n, xc P c X coordinate value in the camera coordinate system, y c P c The Y coordinate value in the camera coordinate system, z c P c The Z coordinate value in the camera coordinate system. Find the least squares solution to the above overdetermined equations to get the center point P of the ball c The coordinate value x c ,y c 、z c .

[0066] Experiment: According to the method described in the present invention, a three-dimensional vertical line measurement system based on structured light (hereinafter referred to as the system) is constructed on the Windows platform. A vertical line displacement measurement experiment is carried out on a laboratory mobile platform. A high-precision grating ruler and guide rail are used to control the vertical line to move 5 mm each time. The measured vertical line displacement is compared with the grating ruler reading, and the error is calculated. The experimental data are shown in Tables 1 and 2:

[0067] Table 1: Vertical X-direction displacement measurement test results (unit: mm)

[0068]

[0069] Table 2: Vertical Y-direction displacement measurement test results (unit: mm)

[0070]

[0071] The displacement of the vertical line in the Z direction is difficult to control accurately, so two small balls are hung on the vertical line, and the distance between the two small balls is measured by the above method and compared with the distance measured by a vernier caliper. The experimental data are shown in Table 3:

[0072] Table 3: Vertical Z-direction displacement measurement test results (unit: mm)

[0073]

[0074] In summary, in view of the problems that the existing vertical coordinate measuring machine can only measure the displacement in two directions of the plane, has a small measurement range, and a complex instrument structure, the present invention is based on the principle of laser triangulation, selects a suitable camera and lens, constructs a structured light measurement system, and fixes a small ball on the vertical line to achieve simultaneous measurement of the displacement of the vertical line in three directions, with high accuracy, large measurement range, fast measurement speed, simple structure, and high reliability. The experimental results confirm that the method proposed in the present invention can simultaneously measure the displacement of the vertical line in three directions, and the measurement accuracy meets the requirements.

[0075] It should be understood that parts not elaborated in detail in this specification belong to the prior art.

[0076] Although the terms such as computer, CCD camera, line laser transmitter, vertical line to be measured, bracket, ball, etc. are used more frequently in this article, the possibility of using other terms is not excluded. The use of these terms is only for the purpose of more conveniently describing the essence of the present invention, and interpreting them as any additional restrictions is contrary to the spirit of the present invention.

[0077] It should be understood that the above description of the preferred embodiment is relatively detailed and cannot be regarded as limiting the scope of patent protection of the present invention. Under the enlightenment of the present invention, ordinary technicians in this field can also make substitutions or modifications without departing from the scope of protection of the claims of the present invention, which all fall within the scope of protection of the present invention. The scope of protection requested for the present invention shall be based on the attached claims.

Claims

1. A structured light three-dimensional vertical line measurement method of a structured light three-dimensional vertical line measurement device, characterized in that: The structured light three-dimensional vertical line measuring device comprises: a computer, a CCD camera, a line laser transmitter, a vertical line to be measured, a bracket, and a small ball; The CCD camera is connected to the computer; The line laser transmitter is placed below the CCD camera, facing the vertical line to be measured, and transmits a horizontal laser plane; The small ball is fixed on the vertical line to be measured, and the vertical line to be measured is suspended in front of the CCD camera through the bracket; The structured light three-dimensional vertical line measurement method comprises the following steps: Step 1: The computer calibrates the principal point, focal length and distortion parameters of the CCD camera through the Zhang Zhengyou camera calibration method to obtain the principal point, focal length and distortion parameters of the calibrated camera; Step 2: The computer calibrates the laser plane parameters by a line structure calibration method based on a chessboard to obtain the laser plane equation parameters; Step 3: Place the chessboard vertically in front of the CCD camera, and the computer uses the CCD camera to collect the first-pose chessboard image, extract the first-pose image coordinates of the chessboard corner points and the first-pose world coordinates in the local chessboard world coordinate system, calculate the first pose of the local chessboard world coordinate system, calculate the first-pose camera coordinates of the chessboard corner points in the camera coordinate system, and calculate the first-pose camera coordinates of the chessboard corner points in the camera coordinate system by the least squares fitting method to obtain the normal vector of the first-pose chessboard plane; Step 4: After rotating the chessboard by a certain angle, the computer collects the second posture chessboard image through the CCD camera, extracts the second posture image coordinates of the chessboard corner points and the second posture world coordinates in the local chessboard world coordinate system, calculates the second posture camera coordinates of the chessboard corner points in the camera coordinate system, and calculates the second posture camera coordinates of the chessboard corner points in the camera coordinate system by the least squares fitting method to obtain the normal vector of the second posture chessboard plane; Step 5: Perform cross multiplication on the normal vector of the first posture chessboard plane and the normal vector of the second posture chessboard plane to obtain the vertical direction vector calibration parameter; Step 6: The computer controls the CCD camera to capture the panoramic image, and performs distortion correction on the panoramic image in combination with the CCD camera distortion parameters to obtain the distortion-corrected image. The image coordinates of the light point where the horizontal laser plane intersects the vertical line are extracted, and the image coordinates of the center point of the ball are extracted. The analytical equation of the vertical line and the light equation of the projection imaging of the center point of the ball are constructed, and the displacement of the vertical line in the three directions of X, Y, and Z is obtained by solving.

2. The structured light three-dimensional vertical line measurement method of the structured light three-dimensional vertical line measurement device according to claim 1, characterized in that: The first posture image coordinates of the checkerboard corner points and the first posture world coordinates in the local checkerboard world coordinate system are extracted in step 3, specifically: The computer processes the first posture checkerboard image using a checkerboard corner point extraction algorithm to extract the first posture image coordinates of the checkerboard corner points and the first posture world coordinates in a local checkerboard world coordinate system.

3. The structured light three-dimensional vertical line measurement method of the structured light three-dimensional vertical line measurement device according to claim 1, characterized in that: The first posture of the local chessboard world coordinate system is calculated in step 3, specifically: The computer uses a PnP algorithm to combine the first posture image coordinates of the checkerboard corner point and the first posture world coordinates of the checkerboard corner point in the local checkerboard world coordinate system to calculate the first posture of the local checkerboard world coordinate system; The first posture camera coordinates of the chessboard corner points in the camera coordinate system are calculated in step 3, specifically: Combining the calibrated camera principal point, the calibrated camera focal length, the calibrated camera distortion parameters, and the first pose of the local chessboard world coordinate system, the first pose camera coordinates of the chessboard corner points in the camera coordinate system are calculated through the camera imaging model.

4. The structured light three-dimensional vertical line measurement method of the structured light three-dimensional vertical line measurement device according to claim 1, characterized in that: The second posture image coordinates of the checkerboard corner points and the second posture world coordinates in the local checkerboard world coordinate system are extracted in step 4 as follows: The computer processes the second posture checkerboard image using a checkerboard corner point extraction algorithm to extract the second posture image coordinates of the checkerboard corner points and the second posture world coordinates in a local checkerboard world coordinate system.

5. The structured light three-dimensional vertical line measurement method of the structured light three-dimensional vertical line measurement device according to claim 1, characterized in that: Step 4 calculates the second pose of the local chessboard world coordinate system as follows: The computer uses a PnP algorithm to combine the second posture image coordinates of the checkerboard corner points and the second posture world coordinates of the checkerboard corner points in the local checkerboard world coordinate system to calculate the second posture of the local checkerboard world coordinate system; The second posture camera coordinates of the chessboard corner points in the camera coordinate system are calculated in step 4, specifically: Combining the calibrated camera principal point, the calibrated camera focal length, the calibrated camera distortion parameters, and the second pose of the local chessboard world coordinate system, the second pose camera coordinates of the chessboard corner points in the camera coordinate system are calculated through the camera imaging model.

6. The structured light three-dimensional vertical line measurement method of the structured light three-dimensional vertical line measurement device according to claim 1, characterized in that: The image coordinates of the light point where the horizontal laser plane intersects the vertical line in step 6 are specifically: The image after distortion correction is processed by extracting the image coordinates of the light point where the horizontal laser plane intersects the vertical line through median filtering, binarization, and grayscale centroid method; The image coordinates of the center point of the ball are extracted in step 6, specifically: The computer uses morphological filtering and connected domain analysis to extract the image block containing the ball from the distortion-corrected image, and uses Gaussian filtering, canny edge extraction, and ellipse fitting to extract the image coordinates of the center point of the ball from the image block containing the ball.

7. The structured light three-dimensional vertical line measurement method of the structured light three-dimensional vertical line measurement device according to claim 1, characterized in that: The analytical equation for constructing the vertical line described in step 6 is specifically: The computer combines the laser plane equation parameters, solves the coordinates of the light spot through the principle of laser triangulation, and constructs the analytical equation of the vertical line by combining the vertical line direction vector calibration parameters; The light equation of the projection imaging of the center point of the ball in step 6 is specifically: The computer combines the calibrated camera principal point, calibrated camera focal length, and calibrated camera distortion parameters to construct the light equation of the projection imaging of the center point of the ball according to the camera imaging model.

8. The structured light three-dimensional vertical line measurement method of the structured light three-dimensional vertical line measurement device according to claim 1, characterized in that: Step 6 solves the displacement of the vertical line in the three directions of X, Y, and Z, specifically: The computer combines the analytical equation of the perpendicular line and the light equation of the projection imaging of the center point of the ball to solve the coordinates of the center point of the ball. The change in the coordinates of the center point of the ball is the displacement of the perpendicular line in the X, Y, and Z directions.

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