Laser and visible light combined tunnel surrounding rock convergence monitoring method

Abstract

The invention discloses a laser and visible light combined tunnel surrounding rock convergence monitoring method, which combines an image recognition technology based on an optical camera and a single-point elevation measurement technology based on a laser measuring instrument, and comprises the following steps of: firstly, recognizing reflecting parts and roughly calculating coordinates of central points of the reflecting parts; the coordinates are used as tracking targets to enable the laser measuring instrument to automatically track the reflecting part bodies, then the laser measuring instrument accurately measures elevation information of all the reflecting parts, obtained elevation value data of all the reflecting parts can be timely transmitted to a cloud end according to a monitoring period, the cloud end carries out data analysis and processing according to actual needs, and the monitoring efficiency is improved. And generating a curve and a report that the coordinates of the single point change along with time so as to monitor and early warn the convergence condition of the tunnel surrounding rock. According to the invention, automatic monitoring and automatic data analysis processing of tunnel surrounding rock convergence conditions are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel deformation measurement, and in particular relates to a tunnel surrounding rock convergence monitoring method combining laser and visible light. Background Art

[0002] In tunnel engineering, the convergence of tunnel surrounding rock is a very important monitoring indicator. At present, the main monitoring methods are 3D scanner and total station monitoring. The amount of data monitored by 3D scanner is relatively large, and it is difficult to achieve full automatic monitoring because of the large amount of data transmission, which makes it difficult to achieve automatic data processing; the amount of data from the total station is small, but it generally requires manual measurement, and it is also difficult to achieve automatic monitoring. Therefore, a tunnel surrounding rock convergence monitoring method that can achieve automatic monitoring is needed. Summary of the invention

[0003] The purpose of the present invention is to solve the deficiencies of the prior art and to provide a tunnel surrounding rock convergence monitoring method combining laser and visible light.

[0004] The technical solution adopted to achieve the purpose of the present invention is:

[0005] A tunnel surrounding rock convergence monitoring method using a combination of laser and visible light comprises the following steps:

[0006] Step 1: According to the actual measurement requirements, multiple reflectors are arranged on the surface of the tunnel surrounding rock. The reflectors use 360 ​​prisms;

[0007] Step 2: Arrange a patrol car in the tunnel, and set a depth camera and a laser measuring instrument on the patrol car. The laser measuring instrument has the function of rotation adjustment around its Z axis and rotation adjustment around its X axis. The Z axis refers to the direction along the height of the tunnel, the X axis refers to the direction along the length of the tunnel, and the Y axis refers to the direction along the width of the tunnel;

[0008] Step 3: Use the above inspection vehicle to inspect along the tunnel. After the inspection vehicle arrives at the inspection point, perform the following steps:

[0009] Step 3.1: Use a depth camera to take a picture of the tunnel surrounding rock surface, identify the reflectors based on the photographed image, and calculate the center point coordinate information of each reflector in the camera coordinate system;

[0010] Step 3.2: Transform the coordinates of the center point of the reflector obtained in step 3.1 in the camera coordinate system to the laser measuring instrument coordinate system, and use the laser measuring instrument to automatically track each reflector in turn. The specific steps are as follows:

[0011] Step 3.21: Construct the spatial pose transformation relationship from the camera coordinate system c to the laser measuring instrument coordinate system t, and transform the coordinates of the center point of the reflector obtained in step 3.1 in the camera coordinate system to the laser measuring instrument coordinate system;

[0012] Step 3.22: The laser measuring instrument uses the center point coordinates of the reflector obtained in step 3.21 in the laser measuring instrument coordinate system t as the tracking target P, and automatically generates the tracking control parameters of the laser measuring instrument in the laser measuring instrument coordinate system t. The tracking control parameters include: X-axis rotation angle θ tx and the Z-axis rotation angle θ tz , Then the laser measuring instrument automatically adjusts the rotation angles of the Z and X axes according to the above tracking control parameters to reach the target position;

[0013] Step 3.23: Determine whether the target position reached by the laser measuring instrument in step 3.22 is aligned with the target reflector P; if the laser measuring instrument receives the reflection signal of the target reflector P, it means that the laser measuring instrument is aligned with the target reflector P, and then execute step 3.25; if the laser measuring instrument does not receive the reflection signal of the target reflector P, it means that the laser measuring instrument is not aligned with the target reflector P, and then execute step 3.24;

[0014] Step 3.24: If the laser measuring instrument is not aimed at the target reflector P, define the current target point that the laser measuring instrument is aimed at as P1. First, rotate the laser measuring instrument clockwise or counterclockwise around the Z axis to the set fine-tuning angle θ. tΔz , so that the laser measuring instrument is offset from point P1 to point P2, the distance between point P1 and point P2 is ΔS, and ΔS is the set step value, then the fine adjustment angle θ tΔz The calculation formula is:

[0015] in is the distance between the center O of the laser measuring instrument and the target reflector P, and the distance OP is considered to be approximately equal to OP1, so as to construct a plane a P1b perpendicular to the current line of sight OP1 of the laser measuring instrument, and the points P1 and P2 are both on the plane a P1b; the set step value ΔS is smaller than the cross-sectional length dimension of the reflector;

[0016] Then, the laser measuring instrument is controlled to search counterclockwise or clockwise with the set step value ΔS as the radius and point P1 as the center. If the target reflector P is found, step 3.25 is executed; if the target reflector P is still not found after searching for one week, the laser measuring instrument continues to increase a step value ΔS as a new search radius and searches, and the step value ΔS is gradually increased until the target reflector P is found or the set maximum number of searches is reached;

[0017] Step 3.25: After the laser measuring instrument is aimed at the target reflector P, the precise distance S and vertical angle a of the target reflector are measured, and then the elevation value H of each reflector is calculated according to the measured distance S and vertical angle a of each reflector, H=sina·S;

[0018] Step 4: According to the set monitoring cycle, calculate the new center point coordinate data of each reflector in the camera coordinate system according to step 3.1, and then measure the new elevation value of each reflector according to step 3.2 based on the new center point coordinate data of each reflector in the camera coordinate system; transmit the obtained elevation value data of each reflector to the cloud in time according to the monitoring cycle, and the cloud performs data analysis and processing to generate a curve and report of the change of single-point coordinates over time, which is used to monitor and warn the convergence of the surrounding rock.

[0019] In the above technical solution, step 3.1 includes the following steps:

[0020] Step 3.11, use Gaussian function to smooth the image;

[0021] Step 3.12: For the smoothed image, the Sobel gradient operator is used to calculate the finite difference of the first-order partial derivative between adjacent pixels to calculate the magnitude and direction of the gradient of each pixel;

[0022] Step 3.13, filter non-maximum values;

[0023] Step 3.14: Use upper and lower thresholds to detect edges. Points greater than the upper threshold are detected as edge points, and points less than the lower threshold are detected as non-edge points. Points between the upper and lower thresholds are detected as weak edge points. If they are adjacent to pixels that are determined to be edge points, they are determined to be edge points, otherwise they are non-edge points.

[0024] Step 3.15: After the edge detection of the reflector is completed, the intersection point of the straight line fitted with the cross line of the identified reflector edge data is obtained, and the coordinates of the intersection point are used as the coordinates of the center point of the reflector in the pixel coordinate system;

[0025] Step 3.16: Calculate the coordinates of the center point of the reflector in the camera coordinate system based on the coordinates of the center point of the reflector in the pixel coordinate system obtained in step 3.15 above.

[0026] In the above technical solution, the conversion relationship between the coordinates of the center point of the reflector in the pixel coordinate system and the coordinates of the center point in the camera coordinate system is as follows:

[0027]

[0028] in, is the camera's internal parameter matrix, (u, v) is the coordinate of the center point of the reflector in the pixel coordinate system; (X c ,Y c ,Z c ) is the coordinate of the center point of the reflector in the camera coordinate system c.

[0029] In the above technical solution, the relationship between time and camera intrinsic parameters is established in advance, zooming is performed at equal times and intervals starting from the minimum focal length, the camera intrinsic parameters at each focal length are calibrated, and the online search for the camera intrinsic parameters is completed according to the zoom time.

[0030] In the above technical solution, in step 3.25, the laser measuring instrument can be used to illuminate the known reference fixed point on the scene to determine the elevation value Z of the laser measuring instrument in the world coordinate system. to , and then we can get the elevation value of the reflector in the world coordinate system Ho = sina·S + Z to .

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention combines the camera-based image recognition technology and the laser-based single-point elevation measurement technology. The reflectors are first identified and the coordinates of the center points of each reflector are roughly calculated. The coordinates are used as the tracking target to enable the laser measuring instrument to automatically track the reflector body. The laser measuring instrument is then used to accurately measure the elevation information of each reflector. The obtained elevation value data of each reflector will be transmitted to the cloud in a timely manner according to the monitoring cycle. The cloud will perform data analysis and processing according to actual needs, and generate a curve and report of the change of single-point coordinates over time, so as to monitor and warn the convergence of the tunnel surrounding rock. In summary, the present invention realizes the automated monitoring of the tunnel surrounding rock convergence and automated data analysis and processing.

[0033] 2. In view of the situation that the laser measuring instrument is not aimed at the target reflective member, the present invention designs an automatic search method, which can effectively and quickly search for the target reflective member.

[0034] 3. The data volume of the present invention is controllable. The number of reflectors to be monitored can be set according to actual needs, avoiding the disadvantage that the large amount of data used in the three-dimensional scanner monitoring method is difficult to transmit and process. The measurement accuracy of the present invention is high. The reflectors on the tunnel surrounding rock are accurately measured using a laser measuring instrument, which improves the monitoring accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the deployment of reflectors in the tunnel surrounding rock and inspection vehicles in the tunnel.

[0036] Figure 2 It is a coordinate transformation diagram of the tracking control parameters of the laser measuring instrument in its own coordinate system.

[0037] Figure 3 This is a schematic diagram of a laser measuring instrument search.

[0038] Figure 4 This is a schematic diagram of a laser measuring instrument search.

[0039] Figure 5 This is a schematic diagram of a laser measuring instrument search.

[0040] Figure 6 This is a schematic diagram of a laser measuring instrument search.

[0041] Figure 7 This is a schematic diagram of a situation where the step value is greater than the cross-sectional length of the reflector and the search target is missed.

[0042] Figure 8 It is a schematic diagram of a laser measuring instrument measuring the target elevation value.

[0043] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] A laser and visible light combined tunnel surrounding rock convergence monitoring method, see Appendix Figure 1 , including the following steps:

[0046] Step 1: See attached Figure 1 According to the actual measurement requirements, multiple reflectors 1 are arranged on the surface of the tunnel surrounding rock. The reflectors use 360 ​​prisms. The center of the prism can be directly seen at any angle through the 360 ​​prism to avoid the influence of positioning differences of different prism surfaces and prism deflection.

[0047] Step 2: deploy a patrol car 2 in the tunnel, and set a depth camera 21 and a laser measuring instrument 22 on the patrol car. The laser measuring instrument has the function of rotation adjustment around its Z axis and rotation adjustment around its X axis. The Z axis refers to the direction along the height of the tunnel, the X axis refers to the direction along the length of the tunnel, and the Y axis refers to the direction along the width of the tunnel.

[0048] Step 3: Use the above inspection vehicle 2 to inspect along the tunnel. After the inspection vehicle 2 arrives at the inspection point, perform the following steps:

[0049] Step 3.1: Use a depth camera to take a picture of the tunnel surrounding rock surface, identify the reflective elements based on the photographed image, and calculate the center point coordinate information of each reflective element in the camera coordinate system.

[0050] In this embodiment, in order to more accurately and quickly identify the reflective element in the image, the canny operator is used to detect the edge of the reflective element and identify the outline of the reflective element. Since the canny operator is a second-order differential operator, two different thresholds are used to detect strong edges and weak edges respectively, and the optimal edge can be found. Compared with the edge extracted by the first-order differential operator, it not only has better effect but also has strong noise resistance. The specific steps are as follows:

[0051] Step 3:11: Noise reduction, use Gaussian function to smooth the image. For the pixel at position (x, y), its gray value is f(x, y), and the gray value after Gaussian filtering is:

[0052]

[0053] Among them, σ is the smoothness control parameter of Gaussian filtering. The larger σ is, the smoother the image is.

[0054] Step 3.12: Calculate the gradient magnitude and gradient direction. Use the Sobel gradient operator to calculate the finite difference of the first-order partial derivative between adjacent pixels to calculate the magnitude and direction of the gradient of each pixel after Gaussian filtering:

[0055] E x (x,y)=A x ×g σ (x,y)

[0056] E y (x,y)=A y ×g σ (x,y)

[0057] Among them, A x and A y is the Sobel gradient operator, E x is the horizontal difference, E y is the vertical difference, then the gradient magnitude E(x,y) and gradient direction θ(x,y) are:

[0058]

[0059] Step 3.13: Filter non-maxima. In the Gaussian filtering process, the edge may be magnified to make the edge width as close to 1 pixel as possible. If the gradient amplitude of the point is the largest in the area where the point is located, then the point is a possible edge point. Otherwise, it is not. Suppression measures are taken to set the gray value to 0.

[0060] Step 3.14: Use upper and lower thresholds to detect edges. Points greater than the upper threshold are detected as edge points, and points less than the lower threshold are detected as non-edge points. Points between the upper and lower thresholds are detected as weak edge points. If they are adjacent to pixels determined to be edge points, they are determined to be edge points, otherwise they are non-edge points.

[0061] Step 3.15: After the edge detection of the reflector is completed, the intersection point of the straight line fitted with the cross line of the identified reflector edge data is obtained, and the coordinates of the intersection point are used as the coordinates of the center point of the reflector in the pixel coordinate system.

[0062] Step 3.16: Based on the center point coordinates of the reflector in the pixel coordinate system obtained in step 3.15 above, calculate the center point coordinates of the reflector in the camera coordinate system.

[0063] The conversion relationship between the center point coordinates of the reflector in the pixel coordinate system and the center point coordinates in the camera coordinate system is as follows:

[0064]

[0065] in, is the camera's intrinsic parameter matrix, which can be obtained by Zhang Zhengyou's camera calibration method; (u, v) is the coordinate of the center point of the reflector in the pixel coordinate system; (X c ,Y c ,Z c ) is the coordinate of the center point of the reflector in the camera coordinate system c.

[0066] Furthermore, since the focal length of the zoom camera will change during the real-time focusing process, the camera's internal parameters will change. Therefore, it is necessary to establish the relationship between time and camera internal parameters in an offline state, start zooming from the minimum focal length at equal times and intervals, and calibrate the camera internal parameters at each focal length. In this way, the camera internal parameters can be searched online based on the zoom time.

[0067] It should be noted that since this step is based on image recognition technology, the accuracy of the coordinates of the center point of the reflector in the camera coordinate system is not very high. The purpose of this step is to roughly calculate the coordinates of the center point of the reflector first, and then use the coordinates as the tracking target. The laser measuring instrument automatically tracks it, so that the laser measuring instrument can automatically detect the reflector body, and then use the laser measuring instrument to accurately measure the elevation information of the reflector.

[0068] Step 3.2: The coordinates of the center point of the reflector obtained in step 3.1 in the camera coordinate system are transformed into the laser measuring instrument coordinate system, and the laser measuring instrument automatically tracks each reflector in turn to measure the precise elevation value of each reflector.

[0069] The specific steps are as follows:

[0070] Step 3.21: Construct the spatial pose transformation relationship from the camera coordinate system c to the laser measuring instrument coordinate system t, and transform the center point coordinates of the reflector obtained in step 3.1 in the camera coordinate system to the laser measuring instrument coordinate system.

[0071]

[0072] in, is the coordinate of the center point of the reflector in the laser measuring instrument coordinate system t, is the coordinate of the center point of the reflector in the camera coordinate system c, is the rotation amount, θ x ,θ y ,θ z are the angles between the x / y / z axes of the camera coordinate system c and the laser measuring instrument coordinate system t, is the translation amount, They are the horizontal offsets of the x / y / z axes between the camera coordinate system c and the laser measuring instrument coordinate system t.

[0073] Step 3.22: See attached Figure 2 The laser measuring instrument uses the center point coordinates of the reflector obtained in step 3.21 in the laser measuring instrument coordinate system t as the tracking target P, and automatically generates the tracking control parameters of the laser measuring instrument in the laser measuring instrument coordinate system t. The tracking control parameters include: X-axis rotation angle θ tx and the Z-axis rotation angle θ tz , Then the laser measuring instrument automatically adjusts the rotation angles of the Z-axis and X-axis according to the above tracking control parameters to reach the target position.

[0074] Step 3.23: Determine whether the target position reached by the laser measuring instrument in step 3.22 is aligned with the target reflector P; if the laser measuring instrument receives a reflection signal from the target reflector P, it indicates that the laser measuring instrument is aligned with the target reflector P, and then execute step 3.25; if the laser measuring instrument does not receive a reflection signal from the target reflector P, it indicates that the laser measuring instrument is not aligned with the target reflector P, and then execute step 3.24.

[0075] Step 3.24: If the laser measuring instrument is not aimed at the target reflector P, the current target point that the laser measuring instrument is aimed at is defined as P1. At this time, there is a deviation between the current target point P1 and the actual position of the target reflector P. Therefore, the movement of the laser measuring instrument should be adjusted to search for the actual target reflector P. The specific search method designed by the present invention is as follows:

[0076] First, see the attached Figure 3 and attached Figure 4 , rotate the laser measuring instrument clockwise or counterclockwise around the Z axis to the set fine-tuning angle θ tΔz , so that the laser measuring instrument is offset from point P1 to point P2, the distance between point P1 and point P2 is ΔS, and ΔS is the set step value, then the fine adjustment angle θ tΔz The calculation formula is:

[0077] in is the distance between the center O of the laser measuring instrument and the target reflector P (see Appendix Figure 2 ), the distance of OP is considered to be approximately equal to OP1, thereby constructing a plane a P1b perpendicular to the current line of sight OP1 of the laser measuring instrument, and the point P1 and the point P2 are both on the plane a P1b.

[0078] Then, the laser measuring instrument is controlled to search counterclockwise or clockwise with the set step value ΔS as the radius and point P1 as the center. If the target reflector P( Figure 4 ), then execute step 3.25; if the target reflector P is not found after searching for one week ( Figure 5 ), the laser measuring instrument continues to increase a step value ΔS as the new search radius, and searches, and gradually increases the step value ΔS until the target reflector P is found or the set maximum number of searches is reached (if the target reflector is still not found after the maximum number of searches is reached, an error is fed back to the control center). See Appendix Figure 6 , is a schematic diagram of searching for the target reflector after increasing a step value.

[0079] It should be noted that the set step value ΔS is smaller than the cross-sectional length of the reflector, so that during each circular trajectory search by the laser measuring instrument, the search range will not miss the target reflector P (see Appendix Figure 7 , is a schematic diagram showing that the step value ΔS is greater than the cross-sectional length of the reflector and the search target is missed).

[0080] Step 3.25: After the laser measuring instrument is aimed at the target reflector P, refer to the attached Figure 8 , measure the precise distance S and vertical angle a of the target reflector, and then calculate the elevation value H of each reflector based on the measured distance S and vertical angle a information of each reflector, H = sina S, and then calculate the known elevation value Z of the laser measuring instrument in the world coordinate system O to , calculate the elevation value of the reflector in the world coordinate system O: Ho = sina·S + Z to .

[0081] Step 4: According to the set monitoring cycle, calculate the new center point coordinate data of each reflector in the camera coordinate system according to step 3.1, and then measure the new elevation value of each reflector according to step 3.2 based on the new center point coordinate data of each reflector in the camera coordinate system.

[0082] The elevation data of each reflective element obtained will be transmitted to the cloud in a timely manner according to the monitoring cycle. The cloud will perform data analysis and processing according to actual needs, and generate curves and reports of single-point coordinate changes over time, so as to monitor and warn the convergence of the tunnel surrounding rock.

[0083] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A tunnel surrounding rock convergence monitoring method using laser and visible light, characterized in that: The following steps are involved: Step 1: According to the actual measurement requirements, multiple reflectors are arranged on the surface of the tunnel surrounding rock. The reflectors use 360 ​​prisms; Step 2: Arrange a patrol car in the tunnel, and set a depth camera and a laser measuring instrument on the patrol car. The laser measuring instrument has the function of rotation adjustment around its Z axis and rotation adjustment around its X axis. The Z axis refers to the direction along the height of the tunnel, the X axis refers to the direction along the length of the tunnel, and the Y axis refers to the direction along the width of the tunnel; Step 3: Use the above inspection vehicle to inspect along the tunnel. After the inspection vehicle arrives at the inspection point, perform the following steps: Step 3.1: Use a depth camera to take a picture of the tunnel surrounding rock surface, identify the reflectors based on the photographed image, and calculate the center point coordinate information of each reflector in the camera coordinate system; Step 3.2: Transform the coordinates of the center point of the reflector obtained in step 3.1 in the camera coordinate system to the laser measuring instrument coordinate system, and use the laser measuring instrument to automatically track each reflector in turn. The specific steps are as follows: Step 3.21: Construct the spatial pose transformation relationship from the camera coordinate system c to the laser measuring instrument coordinate system t, and transform the coordinates of the center point of the reflector obtained in step 3.1 in the camera coordinate system to the laser measuring instrument coordinate system; Step 3.22: The laser measuring instrument uses the center point coordinates of the reflector obtained in step 3.21 in the laser measuring instrument coordinate system t as the tracking target P, and automatically generates the tracking control parameters of the laser measuring instrument in the laser measuring instrument coordinate system t. The tracking control parameters include: X-axis rotation angle θ tx and the Z-axis rotation angle θ tz , Then the laser measuring instrument automatically adjusts the rotation angles of the Z and X axes according to the above tracking control parameters to reach the target position; Step 3.23: Determine whether the target position reached by the laser measuring instrument in step 3.22 is aligned with the target reflector P; if the laser measuring instrument receives the reflection signal of the target reflector P, it means that the laser measuring instrument is aligned with the target reflector P, and then execute step 3.25; if the laser measuring instrument does not receive the reflection signal of the target reflector P, it means that the laser measuring instrument is not aligned with the target reflector P, and then execute step 3.24; Step 3.24: If the laser measuring instrument is not aimed at the target reflector P, define the current target point that the laser measuring instrument is aimed at as P1. First, rotate the laser measuring instrument clockwise or counterclockwise around the Z axis to the set fine-tuning angle θ. tΔz , so that the laser measuring instrument is offset from point P1 to point P2, the distance between point P1 and point P2 is ΔS, and ΔS is the set step value, then the fine adjustment angle θ tΔz The calculation formula is: in is the distance between the center O of the laser measuring instrument and the target reflector P, and the distance OP is considered to be approximately equal to OP1, so as to construct a plane a P1b perpendicular to the current line of sight OP1 of the laser measuring instrument, and the points P1 and P2 are both on the plane a P1b; the set step value ΔS is smaller than the cross-sectional length dimension of the reflector; Then, the laser measuring instrument is controlled to search counterclockwise or clockwise with the set step value ΔS as the radius and point P1 as the center. If the target reflector P is found, step 3.25 is executed; if the target reflector P is still not found after searching for one week, the laser measuring instrument continues to increase a step value ΔS as a new search radius and searches, and the step value ΔS is gradually increased until the target reflector P is found or the set maximum number of searches is reached; Step 3.25: After the laser measuring instrument is aimed at the target reflector P, the precise distance S and vertical angle a of the target reflector are measured, and then the elevation value H of each reflector is calculated according to the measured distance S and vertical angle a of each reflector, H=sina·S; Step 4: According to the set monitoring cycle, calculate the new center point coordinate data of each reflector in the camera coordinate system according to step 3.1, and then measure the new elevation value of each reflector according to step 3.2 based on the new center point coordinate data of each reflector in the camera coordinate system; transmit the obtained elevation value data of each reflector to the cloud in time according to the monitoring cycle, and the cloud performs data analysis and processing to generate a curve and report of the change of single-point coordinates over time, which is used to monitor and warn the convergence of the surrounding rock.

2. The tunnel surrounding rock convergence monitoring method using laser and visible light combined according to claim 1 is characterized in that: Step 3.1 includes the following steps: Step 3.11, use Gaussian function to smooth the image; Step 3.12: For the smoothed image, the Sobel gradient operator is used to calculate the finite difference of the first-order partial derivative between adjacent pixels to calculate the magnitude and direction of the gradient of each pixel; Step 3.13, filter non-maximum values; Step 3.14: Use upper and lower thresholds to detect edges. Points greater than the upper threshold are detected as edge points, and points less than the lower threshold are detected as non-edge points. Points between the upper and lower thresholds are detected as weak edge points. If they are adjacent to pixels that are determined to be edge points, they are determined to be edge points, otherwise they are non-edge points. Step 3.15: After the edge detection of the reflector is completed, the intersection point of the straight line fitted with the cross line of the identified reflector edge data is obtained, and the coordinates of the intersection point are used as the coordinates of the center point of the reflector in the pixel coordinate system; Step 3.16: Calculate the coordinates of the center point of the reflector in the camera coordinate system based on the coordinates of the center point of the reflector in the pixel coordinate system obtained in step 3.15 above.

3. The tunnel surrounding rock convergence monitoring method using laser and visible light combined according to claim 1 is characterized in that: The conversion relationship between the center point coordinates of the reflector in the pixel coordinate system and the center point coordinates in the camera coordinate system is as follows: in, is the intrinsic parameter matrix of the camera, (u,v) is the coordinate of the center point of the reflector in the pixel coordinate system; (X c ,Y c ,Z c ) is the coordinate of the center point of the reflector in the camera coordinate system c.

4. The tunnel surrounding rock convergence monitoring method using laser and visible light combined according to claim 3 is characterized in that: The relationship between time and camera intrinsic parameters is established in advance. Zooming is performed at equal intervals and at equal times starting from the minimum focal length. The camera intrinsic parameters at each focal length are calibrated. The camera intrinsic parameters are searched online according to the zoom time.

5. The tunnel surrounding rock convergence monitoring method using laser and visible light combined according to claim 1 is characterized in that: In step 3.25, the laser measuring instrument can be used to illuminate the known reference fixed points on site to determine the elevation value Z of the laser measuring instrument in the world coordinate system. to , and then we can get the elevation value of the reflector in the world coordinate system Ho = sina·S + Z to .

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