CN115683059A - Structured light three-dimensional perpendicular line measuring device and method - Google Patents

Abstract

The invention provides a structured light three-dimensional perpendicular line measuring device and method. The method calibrates the parameters of the CCD camera by a Zhang Zhengyou camera calibration method; calibrating laser plane parameters by a checkerboard-based line structured light calibration method; calculating to obtain a vector calibration parameter of the vertical direction by a method of vertically placing the two postures of the checkerboards; the computer controls the CCD camera to collect panoramic images, extracts light spots of the intersection of the laser plane in the horizontal direction and the vertical line and image coordinates of the center point of the small ball, constructs an analytical equation of the vertical line and a light equation of projection imaging of the center point of the small ball by combining calibration parameters, and simultaneously solves to obtain the coordinates of the center point of the small ball, wherein the variable quantity of the coordinates of the center point of the small ball is the displacement of the vertical line in the X direction, the Y direction and the Z direction. The invention has the advantages that three sets of light sources and sensors with the same structure are not required to be respectively configured in three directions, the structure is simplified, and the stability is improved; and a camera and a lens with high resolution are used, a view field is fully utilized, and the measurement precision and the measurement range can be improved.

Description

A structured light three-dimensional vertical measurement device and method

technical field

The method of the invention belongs to the field of computer vision, and in particular relates to a structured light three-dimensional vertical line measuring device and method.

Background technique

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

Perpendicular coordinate instruments can be divided into capacitive, eddy current, photoelectric and other types according to the working principle. The traditional capacitive vertical line coordinate instrument can realize large-scale, high-sensitivity, and high-precision measurement of the vertical line. However, when the measurement environment is humid and dusty, the dielectric constant between the capacitor plates is prone to slow changes, resulting in distortion of the measurement results. CCD sensors are widely used in vertical coordinate instruments due to the advantages of small size, light weight, high integration, low power consumption, good linearity, large dynamic range, long life and strong anti-interference ability. Most of them adopt displacement measurement technology based on linear array CCD sensor. Design method of vertical coordinate instrument based on CCD A vertical coordinate instrument based on linear array CCD is used for mine shaft wall deformation observation. The development method of a new photoelectric vertical coordinate instrument A large-range lensless CCD vertical coordinate instrument has been developed. However, there are still problems such as only two directions of the plane can be measured, the measurement device is repeated, the measuring range is small, and the measurement accuracy is affected by the quality of the parallel light source. On this basis, a three-dimensional vertical coordinate instrument design method based on CCD fixes a disk perpendicular to it on 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 line instrument, the development method of the large-range stepping vertical line coordinate instrument adopts the stepping measurement principle, and the photoelectric probe is driven by the stepping motor to realize the plane two-dimensional displacement measurement. Laser emission and reception are used for position detection. The driving pulse of the motor is counted, and the displacement value is given by calculating the movement distance through the screw lead. A high-speed and high-precision vertical coordinate instrument has developed a high-speed and high-precision vertical coordinate instrument using a similar idea. The instrument uses a grating ruler for displacement measurement. The vertical line meter based on the principle of step-by-step measurement has a complicated structure and high cost because the instrument includes a motor and a screw mechanism.

Contents of the invention

Aiming at 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 high-precision parallel light sources and motor screw mechanisms. It has simple structure, good real-time performance, and adaptability to different environments. powerful.

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

Described CCD camera is connected with shown computer;

The line laser emitter is placed below the CCD camera, towards the vertical line to be measured, and emits a horizontal laser plane;

The bead is fixed on the vertical line to be measured, and the vertical line to be measured is suspended in front of the CCD camera by the bracket;

The technical solution of the method of the present invention is a structured light three-dimensional perpendicular measurement method, comprising the following steps:

Step 1: The computer calibrates the principal point of the CCD camera, the focal length of the CCD camera, and the distortion parameters of the CCD camera through Zhang Zhengyou’s camera calibration method, and obtains the principal point of the calibrated camera, the focal length of the calibrated camera, and the distortion parameters of the calibrated camera;

Step 2: The computer calibrates the laser plane parameters through the checkerboard-based line structure cursor calibration method to obtain the laser plane equation parameters;

Step 3: Place the checkerboard vertically in front of the CCD camera, the computer captures the first pose checkerboard image through the CCD camera, extracts the first pose image coordinates of the corner points of the checkerboard and the first pose in the local checkerboard world coordinate system World coordinates, calculate the first pose of the local checkerboard world coordinate system, calculate the first pose camera coordinates of the checkerboard corner points in the camera coordinate system, and pass the first pose camera coordinates of the checkerboard corner points in the camera coordinate system through the minimum The square fitting method calculates and obtains the normal vector of the first attitude checkerboard plane;

Step 4: After rotating the checkerboard at a certain angle, the computer collects the second pose checkerboard image through the CCD camera, extracts the second pose image coordinates of the corner points of the checkerboard and the second pose world coordinates in the local checkerboard world coordinate system, Calculate the second pose of the local checkerboard world coordinate system, calculate the second pose camera coordinates of the checkerboard corner points in the camera coordinate system, and pass the second pose camera coordinates of the checkerboard corner points in the camera coordinate system through least squares The fitting method calculates the normal vector of the second attitude checkerboard plane;

Step 5: Carry out the cross product of the normal vector of the first posture checkerboard plane and the normal vector of the second posture checkerboard plane to obtain the calibration parameter of the vertical direction vector;

Step 6: The computer controls the CCD camera to collect the panoramic image, and combines the distortion parameters of the CCD camera to correct the distortion of the panoramic image to obtain the distortion-corrected image, extract the image coordinates of the light point where the laser plane in the horizontal direction intersects the vertical line, and extract the center of the ball The image coordinates of the point, construct the analytical equation of the vertical line and the ray equation of the projection imaging of the center point of the ball, and solve the displacement of the vertical line in the three directions of X, Y, and Z

As a preference, step 3 extracts the first posture image coordinates of the checkerboard corner points and the first posture world coordinates under the local checkerboard world coordinate system, specifically:

The computer adopts the checkerboard corner point extraction algorithm to process the first posture checkerboard image, and extracts the first posture image coordinates of the checkerboard corner points and the first posture world coordinates under the local checkerboard world coordinate system;

As a preference, the calculation of the first posture of the local checkerboard world coordinate system described in step 3 is specifically:

The computer adopts the PnP algorithm to calculate the first posture of the local checkerboard world coordinate system in combination with the first pose image coordinates of the checkerboard corner points and the first pose world coordinates of the checkerboard corner points in the local checkerboard world coordinate system;

As a preference, the calculation of the first pose camera coordinates of the checkerboard corner points in the camera coordinate system described in step 3 is specifically:

Combining the principal point of the camera after calibration, the focal length of the camera after calibration, the distortion parameters of the camera after calibration, and the first pose of the local checkerboard world coordinate system, the first pose camera coordinates of the checkerboard corner points in the camera coordinate system are calculated through the camera imaging model ;

As a preference, step 4 extracts the second posture image coordinates of the checkerboard corner points and the second posture world coordinates under the local checkerboard world coordinate system, specifically as follows:

The computer adopts the checkerboard corner point extraction algorithm to process the second posture checkerboard image, and extracts the second posture image coordinates of the checkerboard corner points and the second posture world coordinates under the local checkerboard world coordinate system;

As a preference, the calculation of the second pose of the local checkerboard world coordinate system described in step 4 is as follows:

The computer adopts the PnP algorithm to calculate the second pose of the local checkerboard world coordinate system in combination with the second pose image coordinates of the checkerboard corner points and the second pose world coordinates of the checkerboard corner points in the local checkerboard world coordinate system;

As a preference, the second pose camera coordinates of the checkerboard corner points in the camera coordinate system are calculated in step 4, specifically:

Combining the principal point of the camera after calibration, the focal length of the camera after calibration, the distortion parameters of the camera after calibration, and the second pose of the local checkerboard world coordinate system, calculate the second pose camera coordinates of the checkerboard corner points in the camera coordinate system through the camera imaging model ;

As a preference, the image coordinates of the light spot where the laser plane in the horizontal direction intersects the vertical line as described in step 6 are specifically:

For image processing after distortion correction, the image coordinates of the light point where the laser plane in the horizontal direction intersects the vertical line are extracted through median filtering, binarization, and gray-scale centroid method;

As a preference, the image coordinates of the center point of the small ball extracted in step 6 are specifically:

The computer intercepts the image block containing the ball through morphological filtering and connected domain analysis on the image after distortion correction, and extracts the image coordinates of the center point of the ball through Gaussian filtering, canny edge extraction, and ellipse fitting for the image block containing the ball;

As preferably, the analytical equation of constructing the vertical line described in step 6 is specifically:

Combining the parameters of the laser plane equation, the computer 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 line direction vector;

As a preference, the ray equation for constructing the projection imaging of the center point of the small ball described in step 6 is specifically:

The computer combines the principal point of the camera after calibration, the focal length of the camera after calibration, and the distortion parameters of the camera after calibration, and according to the camera imaging model, constructs the ray equation for projection imaging of the center point of the ball;

As preferably, the solution described in step 6 obtains the displacement of the vertical line in three directions of X, Y, and Z, specifically:

The computer combines the analytical equation of the vertical line and the ray equation of the projection imaging of the center point of the ball, and solves the coordinates of the center point of the ball. displacement.

The advantage of the present invention is that it is based on the principle of laser triangulation distance measurement of line structured light, using a single line structured light source, that is, three-dimensional displacement measurement of vertical lines can be realized, and there is no need to configure three sets of light sources with the same structure in the three directions of X, Y, and Z respectively. and sensors, simplify the structure and improve stability; use high-resolution cameras and lenses to make full use of the field of view, which can improve measurement accuracy and measurement range.

Description of drawings

Figure 1: Schematic diagram of the device structure of the embodiment of the present invention.

Fig. 2: A flow chart of the method of the embodiment of the present invention.

Fig. 3: Schematic diagram of the three-dimensional vertical measurement calibration vertical direction vector of the embodiment of the present invention.

Fig. 4: Schematic diagram of the three-dimensional vertical line measurement of the embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

During specific implementation, the method proposed by the technical solution of the present invention can be implemented by those skilled in the art using computer software technology to realize the automatic operation process. The system device for realizing the method is, for example, a computer-readable storage medium that stores the corresponding computer program of the technical solution of the present invention and includes a computer that runs the corresponding computer program. The computer equipment of the program should also be within the protection scope of the present invention.

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

Described CCD camera is connected with shown computer;

The line laser emitter is placed below the CCD camera, towards the vertical line to be measured, and emits 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 selection of the computer is: i7-7700 CPU, 16GB memory, Windows10 operating system;

The selection of the CCD camera is: JAI GO-5000M-PGE;

The selection of the line laser transmitter is: Hengjiu-100M-16A648-50-GLXS;

The selection of the vertical line to be measured is: white building string;

The type selection of the support is: a laboratory support with a height of 50cm;

The selected ball is a white plastic hollow ball with a diameter of 5 mm.

A structured light three-dimensional vertical line measurement method provided by an embodiment of the present invention is introduced below in conjunction with FIGS. 2-4 , specifically as follows:

Step 1: The computer calibrates the principal point of the CCD camera, the focal length of the CCD camera, and the distortion parameters of the CCD camera through Zhang Zhengyou’s camera calibration method, and obtains the principal point of the calibrated camera, the focal length of the calibrated camera, and the distortion parameters of the calibrated camera;

Step 2: The computer calibrates the laser plane parameters through the checkerboard-based line structure cursor calibration method to obtain the laser plane equation parameters;

Step 3: Place the checkerboard vertically in front of the CCD camera, the computer collects the first posture checkerboard image through the CCD camera, and the computer uses the checkerboard corner extraction algorithm to process the first posture checkerboard image to extract the checkerboard corner points The first pose image coordinates and the first pose world coordinates in the local checkerboard world coordinate system; the computer adopts the PnP algorithm, combining the first pose image coordinates of the checkerboard corner points and the checkerboard corner points in the local checkerboard world coordinate system calculate the first pose of the local checkerboard world coordinate system; combine the calibrated camera principal point, calibrated camera focal length, calibrated camera distortion parameters, and the first pose of the local checkerboard world coordinate system, through The camera imaging model calculates the first pose camera coordinates of the checkerboard corner points in the camera coordinate system, and calculates the first pose checkerboard coordinates of the checkerboard corner points in the camera coordinate system through the least squares fitting method the normal vector of the plane;

Step 4: After rotating the checkerboard at a certain angle, the computer collects the second pose checkerboard image through the CCD camera, and the computer uses the checkerboard corner point extraction algorithm to process the second pose checkerboard image to extract the second pose of the checkerboard corner points The image coordinates and the second pose world coordinates in the local checkerboard world coordinate system; the computer uses the PnP algorithm to combine the second pose image coordinates of the checkerboard corner points with the second pose coordinates of the checkerboard corner points in the local checkerboard world coordinate system. Attitude world coordinates, calculate the second pose of the local checkerboard world coordinate system; combined with the calibrated camera principal point, calibrated camera focal length, calibrated camera distortion parameters, and the second pose of the local checkerboard world coordinate system, image through the camera The model calculates the second pose camera coordinates of the checkerboard corner points in the camera coordinate system, and calculates the second pose camera coordinates of the checkerboard corner points in the camera coordinate system through the least squares fitting method to obtain the second pose checkerboard plane normal vector;

Step 5: Carry out the cross product of the normal vector of the first posture checkerboard plane and the normal vector of the second posture checkerboard plane to obtain the calibration parameter of the vertical direction vector;

Step 6: The computer controls the CCD camera to collect panoramic images, and performs distortion correction on the panoramic images combined with the distortion parameters of the CCD camera to obtain a distortion-corrected image; for image processing after distortion correction, median filtering, binarization, and grayscale centroid The method extracts the image coordinates of the light spot where the laser plane in the horizontal direction intersects with the vertical line; the computer intercepts the image blocks containing small balls through morphological filtering and connected domain analysis on the image after distortion correction, and passes Gaussian to the image blocks containing small balls. Filtering, canny edge extraction, and ellipse fitting extract the image coordinates of the center point of the ball; the computer combines the parameters of the laser plane equation, 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 line direction vector; The computer combines the principal point of the camera after calibration, the focal length of the camera after calibration, and the distortion parameters of the camera after calibration, and according to the camera imaging model, constructs the ray equation of the projection imaging of the center point of the ball; the computer combines the analytical equation of the vertical line and the projection imaging of the center point of the ball The ray equation is solved to obtain the coordinates of the center point of the ball, and 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 principle of the three-dimensional vertical line measurement and calibration of the vertical line direction vector in the embodiment of the present invention is shown in Figure 3, where O-uv is the camera imaging plane, and O _c -X _c Y _c Z _c is the camera coordinate system. The checkerboard plane α ₁ is the checkerboard plane in the first posture, and the checkerboard plane α ₂ is the checkerboard plane in the second posture. P _{c, i, j} are the coordinates of a corner point on the checkerboard plane α ₁ in the camera coordinate system, where the subscript c indicates that the coordinate value is based on the camera coordinate system, and the subscript i indicates that the corner point is located in the ith row of the checkerboard , the subscript j indicates that the corner point is located in the jth column of the checkerboard. According to the size of the calibration board used is 11×8, the value range of the subscript i is 1~11, and the value range of the subscript j is 1~8 . P _{w, i, j} are the coordinates of the checkerboard corner point in the i-th row and the jth column in the local checkerboard world coordinate system, where the subscript w indicates that the coordinate value is based on the local checkerboard world coordinate system. p _i,j is the image coordinates of the projection point of the checkerboard corner point in row i and column j. n ₁ is the normal vector of the checkerboard plane α ₁ , n ₂ is the normal vector of the checkerboard plane α ₂ , n is the calibration parameter of the vertical direction vector, where the vertical line is the intersection line of the plane α ₁ and the plane α ₂ , then the vertical The line direction vector can be calculated by the cross product of the normal vectors of the two planes, namely n=n ₁ ×n ₂ .

The three-dimensional vertical measurement principle of the embodiment of the present invention is shown in Figure 4, where O-uv is the camera imaging plane, and O _c -X _c Y _c Z _c is the camera coordinate system. P _c is the center point of the ball, and p is its imaging point. P ₁ is the point where the laser plane intersects the vertical line, and p ₁ is the image point of its imaging. Among them, the ray P _c p projected and imaged by the center point of the ball intersects the vertical line at point P _c , then the equation of the simultaneous ray P _c p and the vertical line equation are:

Among them, f _x is the focal length of the camera in the X direction after calibration, f _y is the focal length of the camera in the Y direction after calibration, u ₀ is the offset in the X direction of the principal point of the camera after calibration, v ₀ is the offset in the Y direction of the principal point of the camera after calibration, n _x is the X direction component of the calibration parameter n of the vertical direction vector, n _y is the Y direction component of the calibration parameter n of the vertical direction vector, n _z is the Z direction component of the calibration parameter n of the vertical direction vector, x _c is P _c The X coordinate value in the camera coordinate system, y _c is the Y coordinate value of P _c in the camera coordinate system, and z _c is the Z coordinate value of P _c in the camera coordinate system. Find the least squares solution to the above overdetermined equations to get the coordinate values x _c , y _c , z _c of the center point P _c of the ball.

Experiment: according to the method of the present invention, a three-dimensional vertical line measurement system (hereinafter referred to as the system) based on structured light is constructed based on the Windows platform, and the vertical line displacement measurement experiment is carried out on the laboratory mobile platform, using a high-precision grating ruler and a guide rail, Control the vertical line to move 5mm each time, compare the measured vertical line displacement with the reading of the grating ruler, and calculate the error. The experimental data are shown in Table 1 and Table 2:

Table 1: Experimental results of displacement measurement in the vertical X direction (unit: mm)

Table 2: Experimental results of displacement measurement in the vertical Y direction (unit: mm)

The displacement of the vertical line in the Z direction is difficult to control precisely, so two small balls are suspended on the vertical line, and the distance between the two small balls is measured by the above method. Compared with the distance measured by the vernier caliper, the experimental data are shown in Table 3 :

Table 3: Experimental results of displacement measurement in the vertical Z direction (unit: mm)

To sum up, in view of the problems that the existing vertical line coordinate instrument can only measure the displacement in two directions of the plane, the measurement range is small, and the instrument structure is complicated, the present invention is based on the principle of laser triangulation, selects a suitable camera and lens, and constructs a structured light The measurement system fixes the small ball on the vertical line at the same time to realize the simultaneous measurement of the displacement of the vertical line in three directions, with high precision, large measurement range, fast measurement speed, simple structure and high reliability. Experimental results prove that the method proposed by the invention can simultaneously measure the displacement in three directions of the vertical line, and the measurement accuracy meets the requirements.

It should be understood that the parts not described in detail in this specification belong to the prior art.

Although terms such as computer, CCD camera, line laser emitter, vertical line to be measured, bracket, and ball are frequently used in this paper, the possibility of using other terms is not excluded. These terms are only used to describe the essence of the present invention more conveniently, and it is against the spirit of the present invention to interpret them as any additional limitation.

It should be understood that the above-mentioned descriptions for the preferred embodiments are relatively detailed, and should not therefore be considered as limiting the scope of the patent protection of the present invention. Within the scope of protection, replacements or modifications can also be made, all of which fall within the protection scope of the present invention, and the scope of protection of the present invention should be based on the appended claims.

Claims (9)

1. A structured light three-dimensional perpendicular measurement device, comprising: the device comprises a computer, a CCD camera, a line laser emitter, a vertical line to be measured, a bracket and a small ball;

the CCD camera is connected with the computer;

the line laser transmitter is placed below the CCD camera, faces the vertical line to be measured and transmits a laser plane in the horizontal direction;

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 support.

2. A structured light three-dimensional perpendicular measuring method using the structured light three-dimensional perpendicular measuring apparatus according to claim 1, comprising the steps of:

step 1: the computer calibrates the CCD camera principal point, the CCD camera focal length and the CCD camera distortion parameter by a Zhang-Zhengyou camera calibration method to obtain a calibrated camera principal point, a calibrated camera focal length and a calibrated camera distortion parameter;

step 2: the computer calibrates the laser plane parameters by a line structured light calibration method based on the checkerboard to obtain laser plane equation parameters;

and step 3: the checkerboard is vertically placed in front of a CCD camera, a computer collects a first posture checkerboard image through the CCD camera, a first posture image coordinate of a checkerboard angular point and a first posture world coordinate under a local checkerboard world coordinate system are extracted, a first posture of the local checkerboard world coordinate system is calculated, a first posture camera coordinate of the checkerboard angular point under the camera coordinate system is calculated, and a normal vector of a first posture checkerboard plane is calculated by the first posture camera coordinate of the checkerboard angular point under the camera coordinate system through a least square fitting method;

and 4, step 4: after rotating the checkerboards for a certain angle, acquiring a second posture checkerboard image by the computer through the CCD camera, extracting a second posture image coordinate of a checkerboard angular point and a second posture world coordinate under a local checkerboard world coordinate system, calculating a second posture of the local checkerboard world coordinate system, calculating a second posture camera coordinate of the checkerboard angular point under the camera coordinate system, and calculating the second posture camera coordinate of the checkerboard angular point under the camera coordinate system through a least square fitting method to obtain a normal vector of a second posture checkerboard plane;

and 5: performing cross multiplication on the normal vector of the first posture checkerboard plane and the normal vector of the second posture checkerboard plane to obtain a calibration parameter of the vector of the vertical direction;

step 6: the computer controls a CCD camera to collect panoramic images, distortion correction is carried out on the panoramic images by combining with distortion parameters of the CCD camera to obtain images after distortion correction, image coordinates of light spots where laser planes in the horizontal direction are intersected with the vertical line are extracted, image coordinates of the central point of the small ball are extracted, an analytical equation of the vertical line and a light equation of projection imaging of the central point of the small ball are constructed, and the displacement of the vertical line in the X direction, the Y direction and the Z direction is obtained through solving.

3. The structured light three-dimensional perpendicular measurement method according to claim 2, characterized in that:

step 3, extracting the first attitude image coordinate of the checkerboard corner point and the first attitude world coordinate under the local checkerboard world coordinate system, specifically:

and the computer processes the first posture checkerboard image by adopting a checkerboard corner extraction algorithm, and extracts the first posture image coordinates of the checkerboard corners and the first posture world coordinates under the local checkerboard world coordinate system.

4. The structured light three-dimensional perpendicular measurement method according to claim 3, wherein:

step 3, calculating the first posture of the local checkerboard world coordinate system, specifically:

the computer adopts a PnP algorithm, and calculates a first posture of a local checkerboard world coordinate system by combining a first posture image coordinate of a checkerboard angular point and a first posture world coordinate of the checkerboard angular point under the local checkerboard world coordinate system;

step 3, calculating the first posture camera coordinate of the checkerboard angular point under the camera coordinate system, specifically:

and calculating a first posture camera coordinate of the checkerboard angular point under the camera coordinate system through a camera imaging model by combining the calibrated camera principal point, the calibrated camera focal length, the calibrated camera distortion parameter and the first pose of the local checkerboard world coordinate system.

5. The structured light three-dimensional perpendicular measurement method according to claim 2, characterized in that:

and 4, extracting a second attitude image coordinate of the checkerboard corner point and a second attitude world coordinate under a local checkerboard world coordinate system, which are specifically as follows:

and the computer processes the second posture checkerboard image by adopting a checkerboard corner extraction algorithm, and extracts the second posture image coordinates of the checkerboard corners and the second posture world coordinates under the local checkerboard world coordinate system.

6. The structured light three-dimensional perpendicular measurement method according to claim 5, wherein:

and 4, calculating a second pose of the local checkerboard world coordinate system, which comprises the following steps:

the computer adopts a PnP algorithm, and calculates a second posture of the local checkerboard world coordinate system by combining a second posture image coordinate of the checkerboard angular point and a second posture world coordinate of the checkerboard angular point under the local checkerboard world coordinate system;

step 4, calculating a second posture camera coordinate of the checkerboard angular point under the camera coordinate system, specifically:

and calculating a second posture camera coordinate of the checkerboard angular point under the camera coordinate system through the camera imaging model by combining the calibrated camera principal point, the calibrated camera focal length, the calibrated camera distortion parameter and a second pose of the local checkerboard world coordinate system.

7. The structured light three-dimensional perpendicular measurement method according to claim 2, wherein:

and 6, taking the image coordinates of the light spot where the laser plane in the horizontal direction intersects with the vertical line, specifically:

processing the image after distortion correction, and extracting image coordinates of light spots where the laser plane in the horizontal direction intersects with the vertical line by median filtering, binarization and a gray level centroid method;

step 6, extracting the image coordinates of the central point of the small ball, specifically:

and the computer intercepts the image blocks containing the pellets through morphological filtering and connected domain analysis on the image after the distortion correction, and extracts the image coordinates of the central points of the pellets through Gaussian filtering, canny edge extraction and ellipse fitting on the image blocks containing the pellets.

8. The structured light three-dimensional perpendicular measurement method according to claim 7, wherein:

step 6, constructing an analytic equation of the vertical line, specifically:

the computer combines the laser plane equation parameters, solves the coordinates of the light spot through the laser triangulation principle, and combines the vertical direction vector calibration parameters to construct an analytical equation of the vertical line;

step 6, constructing a light equation of the projection imaging of the center point of the small ball, specifically:

and the computer combines the principal point of the camera after calibration, the focal length of the camera after calibration and the distortion parameter of the camera after calibration, and constructs a light equation of the projection imaging of the central point of the small ball according to the camera imaging model.

9. The structured light three-dimensional perpendicular measurement method according to claim 8, wherein:

and 6, solving to obtain the displacement of the vertical line in the X direction, the Y direction and the Z direction, wherein the method specifically comprises the following steps:

and (3) the computer simultaneously establishes an analytic equation of the vertical line and a light equation of the projection imaging of the central point of the small ball, and solves to obtain the coordinate of the central point of the small ball, wherein the variable quantity of the coordinate of the central point of the small ball is the displacement of the vertical line in the X direction, the Y direction and the Z direction.

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