Method, device and storage medium for automatic registration of tunnel point cloud

Abstract

The present invention discloses a method, device and storage medium for automatic registration of tunnel point clouds, belonging to the technical field of tunnel construction safety. The method for automatic registration of tunnel point clouds includes: collecting point cloud data S through a solid-state lidar; removing extreme values to obtain the real ground horizontal plane point cloud S MEDIAN ; processing the point cloud S MEDIAN to fit the real ground horizontal plane F h ; extracting the intersection line point cloud S h of the horizontal plane F L and the point cloud S by a spatial method based on the tangent, and processing S L by using the least squares method to fit the intersection line L of the horizontal plane and one side wall of the tunnel; converting the point cloud coordinate matrix in the cloud coordinate system xyz to the real tunnel space coordinate system XYZ; translating the point cloud S i R to obtain the final point cloud coordinates. The present invention also proposes a device and a storage medium for automatic registration of tunnel point clouds. The method for automatic registration of tunnel point clouds proposed by the present invention can achieve efficient and accurate automatic registration of lidar point cloud data.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction safety, and in particular to a method, a device and a storage medium for automatic registration of tunnel point clouds. Background Art

[0002] In recent years, laser scanning technology, especially solid-state laser radar technology, has developed rapidly and has been widely used in tunnel construction and maintenance due to its high precision, high density, real-time and proactive characteristics. Laser radar technology has good applicability in tunnel contour fitting, centerline detection, construction parameter measurement, deformation monitoring, safety monitoring, intrusion detection, etc. Therefore, it has broad application prospects and important practical significance, and can effectively improve the efficiency and safety of tunnel construction and maintenance.

[0003] Conventional LiDAR scanning requires the placement of registration points in the tunnel to determine the relative coordinate system of the point cloud. This method has the disadvantages of low efficiency and great interference with construction and maintenance operations.

[0004] How to efficiently and accurately determine the tunnel point cloud is a technical problem that needs to be solved by the existing technology. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies, provide a method, device and storage medium for automatic registration of tunnel point clouds, and solve the technical problem of how to efficiently and accurately determine tunnel point clouds in the prior art.

[0006] In order to achieve the above technical objectives, the technical solution of the present invention provides a method for automatic registration of tunnel point clouds, comprising the following steps:

[0007] S1, collect point cloud data S through solid-state laser radar;

[0008] S2. Remove extreme values ​​by median method to obtain the real ground horizontal plane point cloud S MEDIAN ;

[0009] S3. Processing point cloud S MEDIAN The real ground level F is obtained by fitting h , horizontal plane F h The normal direction is the Z axis;

[0010] S4. Extraction of horizontal plane F based on tangent spatial method h Intersection point cloud S L , using the least squares method to process S L Fit the intersection line L between the horizontal plane and the side wall of the tunnel. The direction of the intersection line L is the X-axis of the tunnel, and the normal direction of the plane where the Z-axis and the X-axis are located is the Y-axis.

[0011] S5, converting the point cloud coordinate matrix in the cloud coordinate system xyz into the real tunnel space coordinate system XYZ;

[0012] S6. Point cloud S i R The final point cloud coordinates are obtained by translation.

[0013] In any embodiment, in step S3, the fitting point cloud S is processed using the least squares method. MEDIAN Get the true ground level F h .

[0014] In any embodiment, in step S5, the point cloud coordinate matrix in the cloud coordinate system xyz is converted into the real tunnel space coordinate system XYZ using a quaternion method.

[0015] In any implementation, in step S5, the relationship between the quaternion and the axis angle is as follows:

[0016]

[0017] The axis angle is angle = angle * e (x, y, z), qw is the real part of the quaternion, qx, qy, qz are the imaginary parts of the quaternion, and x, y, z represent the three rotation axes respectively;

[0018] Quaternion q = q w +q x i+q y j+q z k;

[0019] The quaternion rotation matrix is:

[0020]

[0021] The rotated point cloud is: S R =S·R.

[0022] In any embodiment, in step S6, the point cloud S of each period is transformed according to the translation matrix i R The final point cloud coordinates are obtained by translation; the translation matrix is: υ, ω and T are the translations in the XYZ directions respectively.

[0023] In any implementation manner, the translation matrix is ​​obtained by matching based on the maximum value comparison of the three axes:

[0024] υ=MAX(X(S i+1 R ))-MAX(X(S i R))

[0025] ω=MAX(Y(S i+1 R ))-MAX(Y(S i R))

[0026] τ=MAX(Z(S i+1 R))-MAX(Z(S i R)).

[0027] In any implementation, in step S6, the final point cloud coordinates are expressed as Among them, S R represents the rotated point cloud, Represents the translation matrix.

[0028] In addition, the present invention also proposes a device for automatic registration of tunnel point clouds, comprising:

[0029] A collection unit, used for collecting point cloud data S through a solid-state laser radar;

[0030] The first processing unit is used to remove extreme values ​​by the median method to obtain the real ground horizontal plane point cloud S MEDIAN ;

[0031] The second processing unit is used to process the point cloud S MEDIAN The real ground level F is obtained by fitting h , horizontal plane F h The normal direction is the Z axis;

[0032] Extraction unit, used to extract the horizontal plane F based on the tangent space method h Intersection point cloud S L , using the least squares method to process S L Fit the intersection line L between the horizontal plane and the side wall of the tunnel. The direction of the intersection line L is the X-axis of the tunnel, and the normal direction of the plane where the Z-axis and the X-axis are located is the Y-axis.

[0033] A conversion unit, used to convert the point cloud coordinate matrix in the cloud coordinate system xyz into the real tunnel space coordinate system XYZ;

[0034] Translation unit, used to translate point cloud Si R The final point cloud coordinates are obtained by translation.

[0035] In addition, the present invention also provides a storage medium on which a computer program is stored, and when the program is executed by a processor, the steps of the above-mentioned method for automatic registration of tunnel point clouds are implemented.

[0036] Compared with the prior art, the beneficial effects of the present invention include: the method for automatic registration of tunnel point clouds proposed by the present invention comprises the following steps: S1, collecting point cloud data S by solid-state laser radar; S2, removing extreme values ​​by median method to obtain the real ground horizontal plane point cloud S MEDIAN ; S3, processing point cloud S MEDIAN The real ground level F is obtained by fitting h , horizontal plane F h The normal direction is the Z axis; S4, the spatial method based on tangent line to extract the horizontal plane F h Intersection point cloud S L , using the least squares method to process S L Fit the intersection line L of the horizontal plane and the side wall of the tunnel. The direction of the intersection line L is the X-axis of the tunnel axis, and the normal of the plane where the Z-axis and the X-axis are located is the Y-axis; S5. Convert the point cloud coordinate matrix in the cloud coordinate system xyz to the real tunnel space coordinate system XYZ; S6. Convert each period of point cloud S i R The final point cloud coordinates are obtained by translation; the method for automatic registration of tunnel point clouds proposed in the present invention can achieve automatic registration of laser radar point cloud data efficiently and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the on-site installation and coordinate system of the laser radar in Example 1 of the present invention.

[0038] Figure 2 This is a single test cloud diagram of Example 1 of the present invention.

[0039] Figure 3 This is one of the cloud images after automatic registration in Example 1 of the present invention.

[0040] Figure 4 This is one of the cloud images after automatic registration in Example 1 of the present invention.

[0041] Figure 5 This is one of the cloud images after automatic registration in Example 1 of the present invention.

[0042] Figure 6 This is one of the cloud images after automatic registration in Example 1 of the present invention. DETAILED DESCRIPTION

[0043] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0044] This specific implementation provides a method for automatic registration of tunnel point clouds, comprising the following steps:

[0045] S1, collect point cloud data S through solid-state laser radar;

[0046] S2. Remove extreme values ​​by median method to obtain the real ground horizontal plane point cloud S MEDIAN ;

[0047] S3. Processing point cloud S using least squares method MEDIAN The real ground level F is obtained by fitting h , horizontal plane F h The normal direction is the Z axis;

[0048] S4. Extraction of horizontal plane F based on tangent spatial method h Intersection point cloud S L , using the least squares method to process S L Fit the intersection line L between the horizontal plane and the side wall of the tunnel. The direction of the intersection line L is the X-axis of the tunnel, and the normal direction of the plane where the Z-axis and the X-axis are located is the Y-axis.

[0049] S5. Use the quaternion method to convert the point cloud coordinate matrix in the cloud coordinate system xyz to the real tunnel space coordinate system XYZ; the relationship between the quaternion and the axis angle is as follows:

[0050]

[0051] The axis angle is angle = angle * e (x, y, z), q w is the real part of the quaternion, q x ,q y ,q z Three are the imaginary parts of the quaternion, x, y, and z represent the three rotation axes respectively;

[0052] Quaternion q=q w +q x i+q y j+q z k;

[0053] The quaternion rotation matrix is:

[0054]

[0055] The rotated point cloud is: S R =S·R;

[0056] To apply a rotation transformation to any three-dimensional point P (consider P as a quaternion with a real part of 0) through a quaternion R, you only need to calculate: P' = RPRQ;

[0057] S6, according to the translation matrix, the point cloud Si of each period R The final point cloud coordinates are obtained by translation; the translation matrix is: υ, ω and τ are the translations in the three directions of XYZ respectively; the translation matrix is ​​obtained by matching the maximum values ​​of the three axes:

[0058] υ=MAX(X(S i+1 R))-MAX(X(S i R))

[0059] ω=MAX(Y(S i+1 R ))-MAX(Y(S i R))

[0060] τ=MAX(Z(S i+1 R))-MAX(Z(S i R));

[0061] The final point cloud coordinates are expressed as Among them, S R represents the rotated point cloud, Represents the translation matrix.

[0062] This specific implementation also proposes a device for automatic registration of tunnel point clouds, including:

[0063] A collection unit, used for collecting point cloud data S through a solid-state laser radar;

[0064] The first processing unit is used to remove extreme values ​​by the median method to obtain the real ground horizontal plane point cloud S MEDIAN ;

[0065] The second processing unit is used to process the point cloud S MEDIAN The real ground level F is obtained by fitting h , horizontal plane F h The normal direction is the Z axis;

[0066] Extraction unit, used to extract the horizontal plane F based on the tangent space method h Intersection point cloud S L , using the least squares method to process S L Fit the intersection line L between the horizontal plane and the side wall of the tunnel. The direction of the intersection line L is the X-axis of the tunnel, and the normal direction of the plane where the Z-axis and the X-axis are located is the Y-axis.

[0067] A conversion unit, used to convert the point cloud coordinate matrix in the cloud coordinate system xyz into the real tunnel space coordinate system XYZ;

[0068] Translation unit, used to translate each point cloud Si RThe final point cloud coordinates are obtained by translation.

[0069] In addition, this specific embodiment also proposes a storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the above-mentioned method for automatic registration of tunnel point clouds are performed.

[0070] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0071] The following are examples of the present application. The examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or in the product specifications shall be followed.

[0072] Example 1

[0073] This embodiment provides a method for automatic registration of tunnel point clouds, including the following steps:

[0074] S1. Install the solid-state laser radar in an appropriate position so that the radar mirror is roughly facing the tunnel face. After the radar equipment is basically adjusted to a basically horizontal state, the point cloud data S is collected. At this time, the coordinate system of the radar equipment and the point cloud is: the radar mirror faces the -x axis, the radar side faces the -y axis, and the radar top faces the -z axis. Figure 1 Due to manual installation errors, there is a certain angle difference between the point cloud coordinate system and the real tunnel space coordinate system (the tunnel axis direction is the X axis, the vertical direction is the Z axis, and the direction perpendicular to the XZ plane is the Y axis);

[0075] S2. Since the tunnel ground needs to be passed, it will be repeatedly leveled and can be approximately identified as a horizontal surface. Therefore, after removing the extreme values ​​caused by local unevenness of the ground and incomplete leveling of the equipment, the real ground horizontal surface point cloud S can be obtained by the median method. MEDIAN ;

[0076] S3. The tunnel surface is not completely smooth. The least squares method is used to process S MEDIAN Fitting the true ground level F h , horizontal plane F h The normal direction is the Z axis;

[0077] S4, Extract the horizontal plane F based on the spatial method of tangent h Intersection point cloud S L , using the least squares method to process S LFit the intersection line L of the horizontal plane and the side wall of the tunnel. The direction of the intersection line L is the X-axis of the tunnel axis, and the normal of the plane where the Z-axis and the X-axis are located is the Y-axis. At this point, the X, Y, and Z axes of the real tunnel space coordinate system are all determined. The point cloud coordinate matrix in the point cloud coordinate system xyz must be converted to the real tunnel space coordinate system XYZ.

[0078] S5. Use the quaternion method to convert the point cloud coordinate matrix in the point cloud coordinate system xyz to the real tunnel space coordinate system XYZ. The relationship between the quaternion and the axis angle is as follows:

[0079]

[0080] The axis angle is angle = angle * e (x, y, z), q w is the real part of the quaternion, q x ,q y ,q z Three are the imaginary parts of the quaternion, x, y, and z represent the three rotation axes respectively;

[0081] Quaternion q=q w +q x i+q y j+q z k;

[0082] The quaternion rotation matrix is:

[0083]

[0084] The rotated point cloud is: S R =S·R;

[0085] S6. Combination Figure 2 , according to the translation matrix, the point cloud S of each period i R The final point cloud coordinates are obtained by translation; the translation matrix is: υ, ω and τ are the translations in the three directions of XYZ respectively; the translation matrix is ​​obtained by matching the maximum values ​​of the three axes:

[0086] υ=MAX(X(S i+1 R))-MAX(X(S i R))

[0087] ω=MAX(Y(S i+1 R ))-MAX(Y(S i R))

[0088] τ=MAX(Z(S i+1 R))-MAX(Z(S i R));

[0089] The final point cloud coordinates are expressed as Among them, S R represents the rotated point cloud, Represents the translation matrix.

[0090] The partial cloud image after registration is as follows Figure 3-6 shown.

[0091] In the present invention, reference is made to “some embodiments”, “this embodiment”, examples, etc., which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0092] In this embodiment, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, object A and / or object B may represent three situations: object A exists alone, object A and object B exist at the same time, and object B exists alone.

[0093] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for automatic registration of tunnel point clouds, characterized in that: The following steps are involved: S1, collect point cloud data S through solid-state laser radar; S2. Remove extreme values ​​by median method to obtain the real ground horizontal plane point cloud S MEDIAN ; S3. Processing point cloud S MEDIAN The real ground level F is obtained by fitting h , horizontal plane F h The normal direction is the Z axis; S4, Extract the horizontal plane F based on the spatial method of tangent h Intersection point cloud S L , using the least squares method to process S L Fit the intersection line L between the horizontal plane and the side wall of the tunnel. The direction of the intersection line L is the X-axis of the tunnel, and the normal direction of the plane where the Z-axis and the X-axis are located is the Y-axis. S5, converting the point cloud coordinate matrix in the cloud coordinate system xyz into the real tunnel space coordinate system XYZ; S6. Point cloud S i R Translate to obtain the final point cloud coordinates; In step S5, the point cloud coordinate matrix in the cloud coordinate system xyz is converted to the real tunnel space coordinate system XYZ using the quaternion method. The relationship between the quaternion and the axis angle is as follows: The axis angle is angle = angle * e (x, y, z), q w is the real part of the quaternion, q x ,q y ,q z Three are the imaginary parts of the quaternion, x, y, and z represent the three rotation axes respectively; Quaternion q = q w +q x i+q y j+q z k; The quaternion rotation matrix is: The rotated point cloud is: S R =S·R.

2. The method for automatic registration of tunnel point clouds according to claim 1, characterized in that: In step S3, the least squares method is used to process the fitting point cloud S MEDIAN Get the true ground level F h .

3. The method for automatic registration of tunnel point clouds according to claim 1, characterized in that: In step S6, the point cloud S of each period is transformed according to the translation matrix. i R The final point cloud coordinates are obtained by translation; the translation matrix is: υ, ω and τ are the translations in the XYZ directions respectively.

4. The method for automatic registration of tunnel point clouds according to claim 3, characterized in that: The translation matrix is ​​obtained by matching the maximum values ​​of the three axes: υ=MAX(X(S i+1 R ))-MAX(X(S i R )) ω=MAX(Y(S i+1 R ))-MAX(Y(S i R )) τ=MAX(Z(S i+1 R ))-MAX(Z(S i R ))。 5. The method for automatic registration of tunnel point clouds according to claim 1, characterized in that: In step S6, the final point cloud coordinates are expressed as S = S R +б; where S R represents the rotated point cloud, and б represents the translation matrix.

6. A device for automatic registration of tunnel point clouds, characterized in that: include: A collection unit, used for collecting point cloud data S through a solid-state laser radar; The first processing unit is used to remove extreme values ​​by the median method to obtain the real ground horizontal plane point cloud S MEDIAN ; The second processing unit is used to process the point cloud S MEDIAN The real ground level F is obtained by fitting h , horizontal plane F h The normal direction is the Z axis; Extraction unit, used to extract the horizontal plane F based on the tangent space method h Intersection point cloud S L , using the least squares method to process S L Fit the intersection line L between the horizontal plane and the side wall of the tunnel. The direction of the intersection line L is the X-axis of the tunnel, and the normal direction of the plane where the Z-axis and the X-axis are located is the Y-axis. The conversion unit is used to convert the point cloud coordinate matrix in the cloud coordinate system xyz to the real tunnel space coordinate system XYZ; the point cloud coordinate matrix in the cloud coordinate system xyz is converted to the real tunnel space coordinate system XYZ using the quaternion method. The relationship between the quaternion and the axis angle is as follows: The axis angle is angle = angle * e (x, y, z), q w is the real part of the quaternion, q x ,q y ,q z Three are the imaginary parts of the quaternion, x, y, and z represent the three rotation axes respectively; Quaternion q = q w +q x i+q y j+q z k; The quaternion rotation matrix is: The rotated point cloud is: S R =S·R; Translation unit, used to translate the point cloud S i R The final point cloud coordinates are obtained by translation.

7. A storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the steps of the method for automatic registration of tunnel point clouds as claimed in any one of claims 1 to 5 are implemented.

Images