Endoscope calibration device and calibration method

Abstract

The present invention relates to the technical field of endoscopes, and in particular to an endoscope calibration device and calibration method, wherein the device comprises: a robot, an endoscope pipeline clamping flange, a calibration plate, a calibration table and a calibration computer; the calibration plate is horizontally placed on the calibration table; the base coordinate system X-Y plane of the robot end is parallel to the calibration table; one end of the endoscope pipeline clamping flange is fixed to the robot end, and the other end is detachably mounted with the endoscope to be calibrated, and the lens of the endoscope to be calibrated faces the calibration plate; the robot drives the endoscope to be calibrated to move up and down along the Z axis of the robot base coordinate system, and stops at multiple specified heights in turn; at each specified height, the endoscope to be calibrated collects image information of the calibration plate at the height and sends it to the calibration computer; the calibration computer calibrates the endoscope according to multiple image information collected by the endoscope to be calibrated. The present invention is conducive to realizing batch calibration of endoscopes and improving calibration efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of endoscopes, and more particularly to an endoscope calibration device and a calibration method. Background Art

[0002] Endoscopes have been widely used in the observation and inspection of slender pipes or small openings, such as medical endoscopes and industrial inspection endoscopes. In some cases where precise measurement is required, the three-dimensional shape or specific size of the observed target needs to be restored or measured through the endoscope, which requires the pre-calibration of the imaging parameters of the endoscope, such as the camera lens internal parameters, lens distortion parameters, and structured light parameters.

[0003] Although traditional computer vision or machine vision has provided camera calibration methods and structured light calibration methods, these calibration methods cannot be separated from the prior acquisition of calibration images and data. For the calibration of a large number of products, traditional calibration methods are inefficient and have a low degree of automation.

[0004] Therefore, how to provide a calibration device and method that can realize batch calibration operations on endoscopes is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of this, the present invention provides an endoscope calibration device and a calibration method, which are conducive to realizing batch calibration of endoscopes and improving calibration efficiency.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides an endoscope calibration device, comprising: a robot, an endoscope pipeline clamping flange, a calibration plate, a calibration table and a calibration computer; the calibration plate is horizontally placed on the calibration table; the base coordinate system XY plane of the robot end is parallel to the calibration table;

[0008] One end of the endoscope pipeline clamping flange is fixed to the end of the robot, and the other end is detachably mounted with the endoscope to be calibrated, with the lens of the endoscope to be calibrated facing the calibration plate;

[0009] The robot drives the endoscope to be calibrated to move up and down along the Z axis of the robot base coordinate system, and stops at multiple specified heights in sequence; at each specified height, the endoscope to be calibrated collects image information of the calibration plate at the height, and sends the collected image information to the calibration computer;

[0010] The calibration computer calibrates the endoscope based on multiple image information collected by the endoscope to be calibrated.

[0011] Furthermore, the endoscope pipeline clamping flange has two circular through holes with orthogonal axes, namely a vertical circular through hole and a horizontal circular through hole; the axis of the vertical circular through hole is parallel to the Z axis of the robot base coordinate system; the vertical circular through hole and the horizontal circular through hole are both provided with locking screws for fixing the pipeline.

[0012] Furthermore, the calibration plate includes a checkerboard calibration plate and a laser calibration plate; when the robot drives the endoscope to be calibrated to move upward along the Z axis of the robot base coordinate system, the checkerboard calibration plate is placed on the calibration table; when the robot drives the endoscope to be calibrated to move downward along the Z axis of the robot base coordinate system, the laser calibration plate is placed on the calibration table.

[0013] Furthermore, the checkerboard calibration plate and the laser calibration plate have the same thickness.

[0014] Furthermore, it also includes: an auxiliary light source lighting device; the auxiliary light source lighting device is installed on the calibration table.

[0015] In a second aspect, the present invention provides an endoscope calibration method, which is applicable to the endoscope calibration device as described above, comprising the following steps:

[0016] S1. Place the checkerboard calibration plate horizontally in the calibration work area of ​​the calibration table, and adjust the robot so that the Z axis of its end points vertically to the checkerboard calibration plate at a certain distance H0;

[0017] S2. Install the endoscope to be calibrated into the endoscope pipeline clamping flange, and make the main light direction of the lens perpendicular to the calibration table, adjust the Z-axis height of the robot end and the rotation angle and horizontal position of the checkerboard calibration plate around the vertical direction, so that the checkerboard image of the checkerboard calibration plate occupies the maximum camera field of view of the endoscope to be calibrated, adjust the brightness and viewing angle of the auxiliary light source lighting device, and record the height of the robot at this time as H1;

[0018] S3, control the robot end to start from height H1, The robot moves upward along the Z axis of its base coordinate system, away from the checkerboard calibration plate. During the movement, the X, Y coordinates and posture of the robot end remain unchanged. It moves N times in total to a height of H2, where ;

[0019] Every time the robot executes After moving away from the target, the calibration computer obtains a calibration image, and obtains N+1 chessboard calibration images I_chessbaord_i at different heights Hi, i=0,...,N;

[0020] S4, the calibration computer determines the endoscope lens internal parameters and lens distortion parameters according to the N+1 chessboard images;

[0021] S5, replace the checkerboard calibration board with a laser calibration board, turn on the laser array switch, adjust the laser intensity and the brightness of the auxiliary light source lighting device; control the robot end to start from the height H2, The robot moves downward along the Z axis of the robot base coordinate system and approaches the laser calibration plate. During the movement, the X, Y coordinates and posture of the robot end remain unchanged. It moves N times in total and reaches the height H1 position. A total of N+1 laser spot images are obtained and sent to the calibration computer.

[0022] S6. The calibration computer uses the lens internal parameters and lens distortion parameters obtained in S4 to perform distortion correction on N+1 laser spot images to obtain corrected images I_lasercorrected_j, j=0,..., N, and calibrates the structured light parameters of the endoscope based on the N+1 corrected laser spot images.

[0023] Furthermore, S4 includes:

[0024] After the calibration computer obtains N+1 checkerboard images, the sub-pixel positions of the checkerboard corner points are extracted using the checkerboard corner point detection function;

[0025] Calibration of the intrinsic matrix parameters of endoscope lens using Zhang Zhengyou calibration method And the lens distortion parameter vector D=(k1,k2,p1,p2), where k1,k2 are the radial distortion coefficients of the lens, and p1,p2 are the tangential distortion coefficients;

[0026] Calculate the pose R_i, t_i, i=0,...,N of the physical plane of the chessboard relative to the camera coordinate system each time the endoscope captures an image; where R_i is a 3*3 orthogonal matrix representing the pose, and t_i is a 3*1 vector representing the position.

[0027] Furthermore, in S6, the process of calibrating the structured light parameters of the endoscope by the calibration computer includes:

[0028] Extract the sub-pixel coordinates spot_{I}_j_k of the laser array spot on all corrected laser spot images, j=0,..., N, k=1,..., L, where j is the laser spot image number, L=r*c, is the total number of laser array spots, and r and c are the number of rows and columns of the laser spot array;

[0029] Based on the obtained sub-pixel coordinates of the laser spot on the image, the physical coordinates of the laser spot on the physical plane of the chessboard are calculated by combining the sub-pixel positions of the chessboard corner points obtained in S4 in the calibration image I_chessboard_i and the physical coordinates of the chessboard corner points on their own physical plane;

[0030] Combine the positions R_i and t_i of the checkerboard physical plane obtained in S4 relative to the camera coordinate system each time the endoscope captures an image, and the physical coordinates of the laser spot on the checkerboard physical plane, and reconstruct the three-dimensional spatial coordinates Spot3D_j_k (j=Ni) of the laser spot in the camera coordinate system;

[0031] The spatial coordinates of the k-th laser ray of the laser array in the camera coordinate system are reconstructed using the three-dimensional spatial coordinates Spot3D_j_k (j=Ni) of the N+1 k-th laser spots in the camera coordinate system.

[0032] Furthermore, the calculation method of the physical coordinates of the laser spot on the physical plane of the chessboard is:

[0033] Assume that the 2D physical coordinates of the corner point of the chessboard are X_m, and its image coordinates in the chessboard image I_chessboard_i are x_m. Calculate the homography matrix from the image plane to the physical plane based on the plane point correspondence relationship. ;

[0034] The sub-pixel coordinates of the kth laser spot in the laser spot image I_laserspot_j of j=Ni are obtained as spot_j_k, and its coordinates on the physical plane of the chessboard calibration are:

[0035] ;

[0036] in is the homogeneous coordinate of spot_j_k.

[0037] Furthermore, after reconstructing the spatial coordinates of all k spatial laser rays of the laser array at a certain height in the camera coordinate system, the intersection of the spatial laser rays is obtained, which is the spatial position of the laser light source.

[0038] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention uses a robot to drive the endoscope to be calibrated to different heights in sequence for image acquisition, and after each image acquisition is completed, the image is automatically sent to a calibration computer for calibration. The whole process has a high degree of automation and high calibration efficiency, and is suitable for calibration operations on batches of endoscopes. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0041] Figure 1 A schematic diagram of the structure of the endoscope calibration device provided by the present invention;

[0042] Figure 2 A schematic diagram of the structure of the endoscope pipeline clamping flange provided by the present invention;

[0043] Figure 3 The present invention provides a flow chart of the endoscope calibration method. DETAILED DESCRIPTION

[0044] 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.

[0045] like Figure 1 As shown, an embodiment of the present invention discloses an endoscope calibration device, comprising: a robot 1, an endoscope pipeline clamping flange 2, a calibration plate 3, a calibration table 4 and a calibration computer (not shown in the figure); the calibration plate 3 is horizontally placed on the calibration table 4; the base coordinate system XY plane of the end of the robot 1 is parallel to the calibration table 4;

[0046] One end of the endoscope pipeline clamping flange 2 is fixed to the end of the robot 1, and the other end is detachably mounted with the endoscope 5 to be calibrated, and the lens of the endoscope 5 to be calibrated faces the calibration plate;

[0047] The robot drives the endoscope 5 to be calibrated to move up and down along the Z axis of the robot base coordinate system, and stops at multiple specified heights in sequence; at each specified height, the endoscope 5 to be calibrated collects image information of the calibration plate at that height, and sends the collected image information to the calibration computer;

[0048] The calibration computer calibrates the endoscope according to the multiple image information collected by the endoscope to be calibrated.

[0049] The rear end of the endoscope 5 to be calibrated is connected to the endoscope acquisition control card, which is connected to the calibration computer via USB. The camera image of the endoscope can be transmitted to the calibration computer through the endoscope acquisition control card, and the laser dot matrix on the endoscope can be controlled by the endoscope acquisition control card.

[0050] Among them, Figure 2 As shown, the endoscope pipeline clamping flange 2 has two circular holes with orthogonal axes, namely a vertical circular hole 21 and a horizontal circular hole 22; the endoscope pipeline mounting flange 2 is Z-shaped as a whole, including a first flange mounting part, a second flange mounting part and an intermediate connecting part, the first flange mounting part is connected to the end of the robot, the vertical circular hole 21 and the horizontal circular hole 22 are opened on the second flange mounting part, the axis of the vertical circular hole is perpendicular to the mounting plane of the first flange mounting part, the axis of the horizontal circular hole is parallel to the mounting plane of the first flange mounting part, and the sides of the two circular holes are processed with V-shaped grooves and tightening bolts for fixing the endoscope pipeline to be calibrated. After the endoscope pipeline clamping flange is fixed to the robot, the axis of the vertical circular hole is parallel to the Z axis of the robot base coordinate system.

[0051] The diameters of the vertical circular through hole and the horizontal circular through hole are both 7.5 mm, and an endoscope with a pipeline diameter less than 7 mm can be clamped. The endoscope pipeline of the present invention includes two specifications of pipelines with a diameter of 6 mm and a diameter of 4 mm.

[0052] The present invention selects the corresponding clamping position of the endoscope clamping flange according to whether the endoscope to be calibrated is a side-view lens or a direct-view lens. Specifically, if the endoscope to be calibrated is a side-view pipeline, the pipeline is clamped in the through hole in the horizontal axis direction and ensures that the pipeline lens and the laser array hole are not blocked; if the endoscope to be calibrated is a direct-view pipeline, the pipeline is clamped in the through hole in the vertical axis direction and ensures that the pipeline lens and the laser array hole are not blocked.

[0053] The calibration plate 3 includes a checkerboard calibration plate and a laser calibration plate, and the two calibration plates have the same thickness; when the robot 1 drives the endoscope 5 to be calibrated to move upward along the Z axis of the robot's base coordinate system, the checkerboard calibration plate is placed on the calibration table to provide the endoscope 5 to be calibrated with a checkerboard image of the calibration camera; when the robot 1 drives the endoscope 5 to be calibrated to move downward along the Z axis of the robot's base coordinate system, the laser calibration plate is placed on the calibration table 4 to provide the endoscope 5 to be calibrated with a laser spot image of the calibration laser dot array.

[0054] In a more advantageous embodiment, an auxiliary light source lighting device 6 is further included; the auxiliary light source lighting device 6 is installed on the calibration table 4 and is used to provide auxiliary lighting when acquiring the calibration image, so as to obtain a clear calibration image.

[0055] In other embodiments, Figure 3 As shown, the present invention also provides an endoscope calibration method, which is applicable to the endoscope calibration device as described above, comprising the following steps:

[0056] S1. Preparation for calibration: Place the checkerboard calibration plate horizontally in the calibration work area of ​​the calibration table, and adjust the robot so that the z-axis at its end points vertically to the checkerboard calibration plate and is at a certain distance H0. For example, the size of the checkerboard square can be 1.5mm, with a total of 9 rows and 7 columns of checkerboards; the robot can be the compact human-machine collaborative Elite E63 robot.

[0057] S2. Install the endoscope to be calibrated: install the endoscope to be calibrated into the endoscope pipeline clamping flange, and make the main light direction of the lens perpendicular to the calibration table, adjust the Z-axis height of the robot end and the rotation angle and horizontal position of the checkerboard calibration plate around the vertical direction, so that the checkerboard image of the checkerboard calibration plate occupies the maximum camera field of view of the endoscope to be calibrated, adjust the brightness and viewing angle of the auxiliary light source lighting device, so that the corners of the checkerboard image are clear, and record the robot height at this time as H1.

[0058] When mounting, select the corresponding mounting position on the mounting flange of the endoscope pipeline according to whether the endoscope to be calibrated is a side-view lens or a direct-view lens.

[0059] If the endoscope to be calibrated is a side-view pipeline, install the pipeline clamp in the through hole (horizontal round through hole) in the horizontal axis direction and ensure that the pipeline lens and laser array hole are not blocked;

[0060] If the endoscope to be calibrated is a direct-view pipeline, install the pipeline clamp in the through hole (vertical circular through hole) in the vertical axis direction and ensure that the pipeline lens and laser array hole are not blocked.

[0061] S3, collect chessboard calibration images: control the robot end to start from height H1, The robot moves upward along the Z axis of its base coordinate system, away from the checkerboard calibration plate. During the movement, the X, Y coordinates and posture of the robot end remain unchanged. It moves N times in total to a height of H2, where , It can be 1.5mm, and the N value is 20-30;

[0062] Every time the robot executes After the movement away from the endoscope, the calibration computer obtains a calibration image I_chessboard, and obtains a total of N+1 chessboard calibration images I_chessbaord_i, i=0,...,N, of the endoscope to be calibrated at different heights Hi.

[0063] S4. Calibrate the endoscope lens internal parameters and lens distortion parameters: The calibration computer determines the endoscope lens internal parameters and lens distortion parameters based on N+1 chessboard images, specifically:

[0064] Use OpenCV's checkerboard corner detection function to extract the sub-pixel position of the checkerboard corners;

[0065] Calibration of the intrinsic matrix parameters of endoscope lens using Zhang Zhengyou calibration method And the lens distortion parameter vector D=(k1,k2,p1,p2), where k1,k2 are the radial distortion coefficients of the lens, and p1,p2 are the tangential distortion coefficients;

[0066] Calculate the pose R_i, t_i, i=0,...,N of the physical plane of the chessboard relative to the camera coordinate system each time the endoscope captures an image; where R_i is a 3*3 orthogonal matrix representing the pose, and t_i is a 3*1 vector representing the position.

[0067] S5. Collect laser spot calibration image: replace the checkerboard calibration plate with a laser calibration plate, turn on the laser array switch, adjust the laser intensity and the brightness of the auxiliary light source lighting device to obtain a clearer laser spot image; control the robot end to start from the height H2, The robot moves downward along the Z axis of the robot base coordinate system to approach the laser calibration plate. During the movement, the X, Y coordinates and posture of the robot end remain unchanged. It moves N times to reach the height H1 position, and obtains a total of N+1 laser spot images I_laser_j, j=0,..., N, which are sent to the calibration computer; the spot array is 7*7.

[0068] S6. Calibrate structured light parameters: The calibration computer uses the lens internal parameters and lens distortion parameters obtained in S4 to perform distortion correction on N+1 laser spot images to obtain corrected images I_lasercorrected_j, j=0,..., N, and calibrates the structured light parameters of the endoscope based on the N+1 corrected laser spot images.

[0069] Specifically, the process of calibrating the structured light parameters of the endoscope by the calibration computer includes:

[0070] S61, extracting the sub-pixel coordinates spot_{I}_j_k of the laser array spot on all corrected laser spot images, j=0,..., N, k=1,..., L, where j is the laser spot image number, L=r*c, is the total number of spots of the laser array spot, and r and c are the number of rows and columns of the laser spot array;

[0071] S62, based on the obtained sub-pixel coordinates of the laser spot on the image, combined with the sub-pixel positions of the checkerboard corner points in the calibration image I_chessboard_i obtained in S4 and the physical coordinates of the checkerboard corner points on their own physical plane, calculate the physical coordinates of the laser spot on the physical plane of the checkerboard Specifically:

[0072] Assume that the 2D physical coordinates of the corner point of the chessboard are X_m, and its image coordinates in the chessboard image I_chessboard_i are x_m. The homography matrix Homo_i from the image plane to the physical plane is calculated based on the plane point correspondence to satisfy ,in, is the homogeneous coordinate of X, Homo_i represents a 3*3 matrix, which represents the homography transformation from the image plane coordinates of the point to the physical plane;

[0073] The sub-pixel coordinates of the kth laser spot in the laser spot image I_laserspot_j of j=Ni are obtained as spot_j_k, and its coordinates on the physical plane of the chessboard calibration are ,in is the homogeneous coordinate of spot_j_k.

[0074] S63, combining the physical plane of the chessboard obtained in S4 with the position R_i and t_i of the camera coordinate system when the endoscope captures an image each time, and the physical coordinates of the laser spot on the physical plane of the chessboard , reconstruct the three-dimensional spatial coordinates of the laser spot in the camera coordinate system Spot3D_j_k (j=Ni);

[0075] S64. Reconstruct the spatial coordinates of the kth spatial laser ray of the laser array in the camera coordinate system by using the three-dimensional spatial coordinates Spot3D_j_k (j=Ni) of the N+1 kth laser spots in the camera coordinate system.

[0076] After reconstructing the spatial coordinates of all k spatial laser rays of the laser array at a certain height in the camera coordinate system, the intersection of the spatial laser rays is obtained, which is the spatial position of the laser light source.

[0077] At this point, all the parameters of the structured light endoscope based on laser spot array projection have been obtained and can be used for subsequent structured light measurement tasks.

[0078] The present invention obtains three-dimensional calibration data by using a plane target with the cooperation of a robot through the above-mentioned calibration steps; at the same time, the difficulty of image processing can be reduced by using calibration planes at different heights, and endoscopes with pipelines of different diameters can be fixed by using an endoscope pipeline clamping flange, thereby improving versatility.

[0079] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0080] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An endoscope calibration method, characterized in that: The following steps are involved: S1. Place the checkerboard calibration plate horizontally in the calibration work area of ​​the calibration table, and adjust the robot so that the Z axis of its end points vertically to the checkerboard calibration plate at a certain distance H0; S2. Install the endoscope to be calibrated into the endoscope pipeline clamping flange, and make the main light direction of the lens perpendicular to the calibration table, adjust the Z-axis height of the robot end and the rotation angle and horizontal position of the checkerboard calibration plate around the vertical direction, so that the checkerboard image of the checkerboard calibration plate occupies the maximum camera field of view of the endoscope to be calibrated, adjust the brightness and viewing angle of the auxiliary light source lighting device, and record the height of the robot at this time as H1; S3, control the end of the robot to start from the height H1, and move upward along the Z axis of its base coordinate system at intervals of ΔH, away from the checkerboard calibration plate. During the movement, the X, Y coordinates and posture of the end of the robot remain unchanged. Move N times in total to a height H2, where H2 = H1 + N·ΔH; Every time the robot performs a ΔH away movement, the calibration computer obtains a calibration image, and obtains a total of N+1 chessboard calibration images I_chessbaord_i at different heights Hi, i=0,...,N; S4, the calibration computer determines the endoscope lens internal parameters and lens distortion parameters according to the N+1 chessboard images; S5, replace the checkerboard calibration plate with a laser calibration plate, turn on the laser array switch, adjust the laser intensity and the brightness of the auxiliary light source lighting device; control the robot end to start from the height H2, with an interval of ΔH, move downward along the Z axis of the robot base coordinate system, approaching the laser calibration plate. During the movement, the X, Y coordinates and posture of the robot end remain unchanged. Move N times in total to reach the height H1 position, obtain a total of N+1 laser spot images, and send them to the calibration computer; S6. The calibration computer uses the lens internal parameters and lens distortion parameters obtained in S4 to perform distortion correction on N+1 laser spot images to obtain corrected images I_lasercorrected_j, j=0,...,N, and calibrates the structured light parameters of the endoscope based on the N+1 corrected laser spot images.

2. The endoscope calibration method according to claim 1, characterized in that S4 include: After the calibration computer obtains N+1 checkerboard images, the sub-pixel positions of the checkerboard corner points are extracted using the checkerboard corner point detection function; Using Zhang Zhengyou calibration method to calibrate the internal parameter matrix parameter K∈R of the endoscope lens 3×3 And the lens distortion parameter vector D = (k1, k2, p1, p2), where k1, k2 are the radial distortion coefficients of the lens, and p1, p2 are the tangential distortion coefficients; Calculate the pose R_i, t_i, i=0,...,N of the physical plane of the chessboard relative to the camera coordinate system each time the endoscope captures an image; where R_i is a 3*3 orthogonal matrix representing the pose, and t_i is a 3*1 vector representing the position.

3. The endoscope calibration method according to claim 2, characterized in that: In S6, the process of calibrating the structured light parameters of the endoscope by the calibration computer includes: Extract the sub-pixel coordinates spot_{I}_j_k of the laser array spot on all corrected laser spot images, j=0,...,N, k=1,...,L, where j is the laser spot image number, L=r*c, is the total number of spots of the laser array spot, and r and c are the number of rows and columns of the laser spot array; Based on the obtained sub-pixel coordinates of the laser spot on the image, the physical coordinates of the laser spot on the physical plane of the chessboard are calculated by combining the sub-pixel positions of the chessboard corner points obtained in S4 in the calibration image I_chessboard_i and the physical coordinates of the chessboard corner points on their own physical plane; Combine the positions R_i and t_i of the checkerboard physical plane obtained in S4 relative to the camera coordinate system each time the endoscope captures an image, and the physical coordinates of the laser spot on the checkerboard physical plane, and reconstruct the three-dimensional spatial coordinates Spot3D_j_k (j=Ni) of the laser spot in the camera coordinate system; The three-dimensional spatial coordinates Spot3D_j_k (j=Ni) of the N+1 k-th laser spots in the camera coordinate system are used to reconstruct the spatial coordinates of the k-th laser ray of the laser array in the camera coordinate system.

4. The endoscope calibration method according to claim 3, characterized in that: The calculation method of the physical coordinates of the laser spot on the physical plane of the chessboard is: Assume that the 2D physical coordinates of the corner point of the chessboard are X_m, and its image coordinates in the chessboard image I_chessboard_i are x_m. The homography matrix Homo_i from the image plane to the physical plane is calculated based on the plane point correspondence. The sub-pixel coordinates of the kth laser spot in the laser spot image I_laserspot_j of j=Ni are obtained as spot_j_k, and its coordinates on the physical plane of the chessboard calibration are: in, is the homogeneous coordinate of spot_j_k.

5. The endoscope calibration method according to claim 3, characterized in that: After reconstructing the spatial coordinates of all k spatial laser rays of the laser array at a certain height in the camera coordinate system, the intersection of the spatial laser rays is obtained, which is the spatial position of the laser light source.

6. An endoscope calibration device, characterized in that: The endoscope calibration method according to any one of claims 1 to 5 is adopted, comprising: a robot, an endoscope pipeline clamping flange, a calibration plate, a calibration table and a calibration computer; the calibration plate is horizontally placed on the calibration table; the base coordinate system XY plane of the robot end is parallel to the calibration table; One end of the endoscope pipeline clamping flange is fixed to the end of the robot, and the other end is detachably mounted with the endoscope to be calibrated, with the lens of the endoscope to be calibrated facing the calibration plate; The robot drives the endoscope to be calibrated to move up and down along the Z axis of the robot base coordinate system, and stops at multiple specified heights in sequence; at each specified height, the endoscope to be calibrated collects image information of the calibration plate at the height, and sends the collected image information to the calibration computer; The calibration computer calibrates the endoscope based on multiple image information collected by the endoscope to be calibrated.

7. The endoscope calibration device according to claim 6, characterized in that: The endoscope pipeline clamping flange has two circular through holes with orthogonal axes, namely a vertical circular through hole and a horizontal circular through hole; the axis of the vertical circular through hole is parallel to the Z axis of the robot base coordinate system; the vertical circular through hole and the horizontal circular through hole are both provided with locking screws for fixing the pipeline.

8. The endoscope calibration device according to claim 6, characterized in that: The calibration plate includes a checkerboard calibration plate and a laser calibration plate; when the robot drives the endoscope to be calibrated to move upward along the Z axis of the robot base coordinate system, the checkerboard calibration plate is placed on the calibration table; when the robot drives the endoscope to be calibrated to move downward along the Z axis of the robot base coordinate system, the laser calibration plate is placed on the calibration table.

9. The endoscope calibration device according to claim 8, characterized in that: The chessboard calibration plate and the laser calibration plate have the same thickness.

10. The endoscope calibration device according to claim 6, characterized in that: Also includes: Auxiliary light source lighting device; The auxiliary light source lighting device is installed on the calibration table.

Images