Internal reference calibration method and internal and external reference calibration method of laser radar and laser radar

Abstract

The embodiment of the invention discloses an internal parameter calibration method of a laser radar, an internal and external parameter calibration method and the laser radar. The method comprises the following steps: acquiring multi-frame point clouds obtained by scanning a first calibration plate and a second calibration plate by a laser radar in different attitudes; based on the multiple frames of point clouds, a target yaw internal reference is determined, the target yaw internal reference is a yaw internal reference value capable of enabling each frame of point clouds to obtain a consistent inter-plate distance value, the yaw internal reference value is an increment of a yaw angle corresponding to a data point in the point clouds, and the inter-plate distance value is a distance from the first calibration plate to the second calibration plate. According to the embodiment of the invention, by calibrating the target yaw internal reference, the point cloud distortion reflected on the yaw angle due to the installation error is corrected, and the laser radar can obtain the reliable and accurate point cloud.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of parameter calibration technology, and in particular to an internal parameter calibration method of a laser radar, an internal and external parameter calibration method, and a laser radar. Background Art

[0002] LiDARs are equipped with a scanning device, and the scanning angle of the scanning device affects the field of view of the LiDAR. To expand the field of view, the LiDAR is equipped with a larger scanning space so that the scanning device can increase the scanning angle, but this method tends to increase the size of the LiDAR. Related technologies use an expansion lens to amplify the field of view. This method can achieve a larger field of view without increasing the scanning angle. However, there is an installation error between the scanning device and the expansion lens, which causes distortion in the point cloud collected by the LiDAR. Summary of the Invention

[0003] One purpose of the embodiments of the present application is to provide an internal parameter calibration method, an internal and external parameter calibration method and a laser radar, so as to improve the situation in related technologies where point cloud distortion occurs due to installation errors between the scanning device and the angle expansion lens.

[0004] In a first aspect, an embodiment of the present application provides a method for calibrating the intrinsic parameters of a laser radar, comprising: obtaining a plurality of frames of point clouds obtained by scanning a first calibration plate and a second calibration plate with different postures by a laser radar; determining a target yaw intrinsic parameter based on the plurality of frames of the point cloud, wherein the target yaw intrinsic parameter is a yaw intrinsic parameter value that enables the point cloud of each frame to obtain a consistent inter-plate distance value, the yaw intrinsic parameter value is an increment of the yaw angle corresponding to the data point in the point cloud, and the inter-plate distance value is the distance from the first calibration plate to the second calibration plate.

[0005] The embodiment of the present application calibrates the target yaw internal parameters and corrects the point cloud distortion caused by installation errors in the yaw angle, which is conducive to the laser radar obtaining reliable and accurate point clouds.

[0006] Optionally, determining the target yaw intrinsic parameter based on the point cloud of multiple frames includes: configuring multiple yaw intrinsic parameter values ​​for the point cloud of the same frame, using multiple yaw intrinsic parameter values ​​to update the point cloud of the same frame respectively to obtain multiple inter-board distance values ​​of the point cloud of the same frame, and obtaining the correlation relationship between the yaw intrinsic parameter value and the inter-board distance value corresponding to the point cloud of the same frame based on the multiple yaw intrinsic parameter values ​​of the point cloud of the same frame and the corresponding inter-board distance values; and determining the target yaw intrinsic parameter according to the correlation relationship corresponding to the point cloud of each frame.

[0007] Optionally, obtaining the correlation between the yaw intrinsic parameter values ​​and the inter-board distance values ​​corresponding to the point cloud in the same frame based on the multiple yaw intrinsic parameter values ​​and the corresponding inter-board distance values ​​includes: Linear fitting is performed on multiple yaw intrinsic parameter values ​​of the same-frame point cloud and corresponding inter-plate distance values ​​to obtain a first fitting straight line corresponding to the same-frame point cloud.

[0008] Optionally, determining the target yaw intrinsic parameter according to the correlation relationship corresponding to the multiple frames of point clouds includes: determining the yaw intrinsic parameter value corresponding to the intersection of the first fitting straight line corresponding to the point cloud of each frame as the target yaw intrinsic parameter.

[0009] Optionally, the method also includes: determining the target pitch intrinsic parameter based on multiple frames of the point cloud, wherein the target pitch intrinsic parameter is a pitch intrinsic parameter value that can make the first absolute difference between the ground height of the first target point cloud and the ground height of the third target point cloud equal to the second absolute difference between the ground height of the second target point cloud and the ground height of the third target point cloud, the first field of view corresponding to the first target point cloud and the second field of view corresponding to the second target point cloud are symmetrical about the third field of view corresponding to the third target point cloud, and the pitch intrinsic parameter value is the increment of the pitch angle corresponding to the data point in the point cloud.

[0010] Optionally, determining the target pitch intrinsic parameter based on the point cloud of multiple frames includes: configuring multiple pitch intrinsic parameter values ​​for the point cloud of the same frame, using multiple pitch intrinsic parameter values ​​to update the point cloud of the same frame respectively to obtain multiple ground heights of the point cloud of the same frame, and obtaining the correlation relationship between the pitch intrinsic parameter value corresponding to the point cloud of the same frame and the ground height based on the multiple pitch intrinsic parameter values ​​of the point cloud of the same frame and the corresponding ground heights; and determining the target pitch intrinsic parameter according to the correlation relationship corresponding to the point cloud of each frame.

[0011] Optionally, the correlation relationship between the pitch intrinsic parameter values ​​corresponding to the same-frame point cloud and the ground height is obtained based on the multiple pitch intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground height, including: linearly fitting the multiple pitch intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground height to obtain a second fitting straight line corresponding to the same-frame point cloud.

[0012] Optionally, the point cloud of each frame corresponds to a first pitch line, a second pitch line and a third pitch line, and the first pitch line, the second pitch line and the third pitch line are all second fitting lines. The target pitch intrinsic parameter is determined according to the association relationship corresponding to the point cloud of each frame, including: obtaining a reference pitch intrinsic parameter, determining a first ground height based on the first pitch line and the reference pitch intrinsic parameter, determining a second ground height based on the second pitch line and the reference pitch intrinsic parameter, determining a third ground height based on the third pitch line and the reference pitch intrinsic parameter, calculating a first absolute value of the difference between the first ground height and the second ground height, calculating a second absolute value of the difference between the second ground height and the third ground height, and in response to the first absolute value being equal to the second absolute value, determining the reference pitch intrinsic parameter as the target pitch intrinsic parameter.

[0013] Optionally, the method also includes: determining a target roll intrinsic parameter based on multiple frames of the point cloud, wherein the target roll intrinsic parameter is a roll intrinsic parameter value that enables the point cloud in each frame to obtain a consistent ground height, and the roll intrinsic parameter value is an increment of the roll angle corresponding to the data point in the point cloud.

[0014] Optionally, determining the target roll intrinsic parameter based on the point cloud of multiple frames includes: configuring multiple roll intrinsic parameter values ​​for the point cloud of the same frame, using multiple roll intrinsic parameter values ​​to update the point cloud of the same frame respectively to obtain multiple ground heights of the point cloud of the same frame, and obtaining the correlation relationship between the roll intrinsic parameter value corresponding to the point cloud of the same frame and the ground height based on the multiple roll intrinsic parameter values ​​of the point cloud of the same frame and the corresponding ground heights; and determining the target roll intrinsic parameter according to the correlation relationship corresponding to the point cloud of each frame.

[0015] Optionally, the correlation relationship between the roll intrinsic parameter values ​​corresponding to the same-frame point cloud and the ground height is obtained based on the multiple roll intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground height, including: linearly fitting the multiple roll intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground height to obtain a third fitting straight line corresponding to the same-frame point cloud.

[0016] Optionally, determining the target roll intrinsic parameter according to the association relationship corresponding to the point clouds of each frame includes: determining the roll intrinsic parameter value corresponding to the intersection of the third fitting straight line corresponding to each point cloud as the target roll intrinsic parameter.

[0017] Optionally, the field of view angle range of the laser radar is [m, n], and the multi-frame point cloud obtained by scanning the first calibration plate and the second calibration plate with different postures by the laser radar includes: obtaining the point cloud obtained by scanning the first calibration plate and the second calibration plate in a first posture, the first posture being the posture when the laser line of the m-th field of view angle of the laser radar hits the first calibration plate; obtaining the point cloud obtained by scanning the first calibration plate and the second calibration plate in a second posture, the second posture being the posture when the laser line of the n-th field of view angle of the laser radar hits the second calibration plate; obtaining the point cloud obtained by scanning the first calibration plate and the second calibration plate in a third posture, the third posture being the posture when the laser line of the n-th field of view angle of the laser radar hits the second calibration plate. The posture when the laser line of the field of view angle hits the middle of the first calibration plate and the second calibration plate.

[0018] In a second aspect, an embodiment of the present application provides a method for calibrating the internal and external parameters of a laser radar, including: determining candidate external parameter data of the laser radar, the candidate external parameter data including candidate yaw external parameters, candidate pitch external parameters and candidate roll external parameters, and obtaining target internal parameter data obtained based on the above-mentioned internal parameter calibration method, the target internal parameter data including target yaw internal parameters, target pitch internal parameters and target roll internal parameters.

[0019] Optionally, the candidate extrinsic parameter data includes candidate yaw extrinsic parameters, and the candidate extrinsic parameter data for determining the lidar includes: obtaining true ground data, the true ground data is used to represent the true ground of the calibration site, and the first calibration plate and the second calibration plate are spaced apart and arranged on the calibration site; determining a first normal vector of the true ground based on the true ground data, and determining a second normal vector of the actual ground based on the point cloud, the actual ground being the ground of the calibration site detected by the lidar, and determining a first angle between the first normal vector and the second normal vector, the first angle being the candidate yaw extrinsic parameter.

[0020] Optionally, the candidate extrinsic parameter data includes candidate pitch extrinsic parameters, and determining the candidate extrinsic parameter data of the lidar includes: obtaining true value plate surface data, the true value plate surface data is used to represent the true value plate surface corresponding to the first calibration plate and the second calibration plate, determining the third normal vector of the true value plate surface based on the true value plate surface data, determining the fourth normal vector of the actual plate surface based on the point cloud, the actual plate surface is the plate surface obtained by the lidar detecting the first calibration plate or the second calibration plate, determining the second angle between the third normal vector and the fourth normal vector, the second angle being the candidate pitch extrinsic parameter.

[0021] Optionally, the candidate extrinsic parameter data includes candidate roll extrinsic parameters, and determining the candidate extrinsic parameter data of the lidar includes: obtaining true ground data and true plate data, the true ground data is used to represent the true ground of the calibration site, and the true plate data is used to represent the true plate corresponding to the first calibration plate and the second calibration plate; determining the first normal vector of the true ground based on the true ground data; determining the third normal vector of the true plate based on the true plate data; cross-producting the first normal vector and the third normal vector to obtain a fifth normal vector; determining the second normal vector of the actual ground and the fourth normal vector of the first calibration plate or the second calibration plate based on the point cloud, the actual ground being the ground of the calibration site detected by the lidar; cross-producting the second normal vector and the fourth normal vector to obtain a sixth normal vector; determining a third angle between the fifth normal vector and the sixth normal vector, the third angle being the candidate roll extrinsic parameter.

[0022] Optionally, the method further includes: updating the candidate extrinsic parameter data based on the target intrinsic parameter data to obtain target extrinsic parameter data, wherein the target extrinsic parameter data includes a target yaw extrinsic parameter, a target pitch extrinsic parameter, and a target roll extrinsic parameter.

[0023] Optionally, the updating of the candidate external parameter data based on the target internal parameter data to obtain the target external parameter data includes: subtracting the target yaw internal parameter of the candidate yaw external parameter by a preset multiple to obtain the target yaw external parameter; subtracting the target pitch internal parameter of the candidate pitch external parameter by a preset multiple to obtain the target pitch external parameter; subtracting the target roll internal parameter of the candidate roll external parameter by a preset multiple to obtain the target roll external parameter.

[0024] In a third aspect, an embodiment of the present application provides a laser radar, comprising a memory and a processor, wherein the memory is connected to the processor, and the processor is used to execute one or more computer programs stored in the memory. When the processor executes the one or more computer programs, the laser radar implements the above-mentioned laser radar internal parameter calibration method or the above-mentioned laser radar internal and external parameter calibration method.

[0025] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program, and the computer program includes program instructions, which, when executed by a processor, enable the processor to execute the above-mentioned laser radar internal parameter calibration method or the above-mentioned laser radar internal and external parameter calibration method. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1 A schematic diagram of the system architecture of a laser radar provided for related technologies; Figure 2 A schematic diagram of a calibration site provided in an embodiment of the present application; Figure 3 A schematic diagram of a flow chart of an external parameter calibration method for a laser radar provided in an embodiment of the present application, wherein: Figure 3 The method shown is used to calibrate candidate yaw extrinsics; Figure 4 A schematic diagram of a flow chart of an external parameter calibration method for a laser radar provided in an embodiment of the present application, wherein: Figure 4 The method shown is used to calibrate candidate pitch extrinsics; Figure 5 A schematic flow chart of an external parameter calibration method for a laser radar provided in another embodiment of the present application, wherein: Figure 5 The method shown is used to calibrate the candidate roll extrinsics; Figure 6 A schematic diagram of a flow chart of an internal parameter calibration method for a laser radar provided in an embodiment of the present application, wherein: Figure 6 The method shown is used to calibrate the target yaw intrinsic parameter; Figure 7 A schematic diagram of a scene in which a laser radar provided in an embodiment of the present application scans a first calibration plate and a second calibration plate in a first posture; Figure 8 A schematic diagram of a scene in which a laser radar provided in an embodiment of the present application scans a first calibration plate and a second calibration plate in a second posture; Figure 9 A schematic diagram of a scene in which a laser radar provided in an embodiment of the present application scans a first calibration plate and a second calibration plate in a third posture; Figure 10 The embodiment of the present application provides an update of the left edge point cloud image using the first yaw intrinsic parameter value and the second yaw intrinsic parameter value; Figure 11 The embodiment of the present application provides an embodiment in which the first yaw intrinsic parameter value and the second yaw intrinsic parameter value are used to update the right edge point cloud; Figure 12 The embodiment of the present application provides an embodiment in which the left edge point cloud is updated using the first rolling intrinsic parameter value and the second rolling intrinsic parameter value; Figure 13 The embodiment of the present application provides an embodiment in which the first rolling intrinsic parameter value and the second rolling intrinsic parameter value are used to update the right edge point cloud; Figure 14 A schematic diagram of the structure of an internal parameter calibration device for a laser radar provided in an embodiment of the present application; Figure 15 A schematic diagram of the structure of an internal and external parameter calibration device for a laser radar provided in an embodiment of the present application; Figure 16 A schematic structural diagram of a laser radar provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] It should be noted that, if there is no conflict, the various features in the embodiments of the present application can be combined with each other and are all within the scope of protection of the present application. In addition, although the functional modules are divided in the device schematic and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a different order than the module division in the device or the order in the flow chart. Furthermore, the words "first", "second", "third", etc. used in this application do not limit the data and execution order, but only distinguish between the same items or similar items with basically the same functions and effects.

[0030] 1. Overview of Related Technologies LiDAR scanning devices are classified into one-dimensional and two-dimensional scanning devices. For example, a one-dimensional scanning device may include a rotating mirror, while a two-dimensional scanning device may include a MEMS galvanometer. Both one-dimensional and two-dimensional scanning devices are linear scanning devices. The laser line is amplified by an optical magnification factor after passing through an expansion lens.

[0031] See also Figure 1 , the galvanometer 11 and the angle-expanding lens 12 are installed relative to each other, and the laser line 13 enters the returning mirror 14, and after being reflected by the returning mirror 14, it enters the galvanometer 11. The galvanometer 11 reflects the laser line 13 to the angle-expanding lens 12, and the angle-expanding lens 12 amplifies the exit angle of the laser line 13 according to the preset optical magnification. Under ideal circumstances, the center of the galvanometer 11 and the center of the angle-expanding lens 12 are on the same horizontal line, so that the laser line reflected by the galvanometer 11 is orthogonal to the exit surface of the angle-expanding lens 12. However, in actual situations, there is an installation error between the galvanometer 11 and the angle-expanding lens 12. The installation error will cause a large difference between the light exit angle at a large angle and the ideal angle, resulting in distortion of the point cloud collected by the lidar.

[0032] 2. Analysis of the principle of distortion of point clouds collected by lidar The position of each data point in the LiDAR point cloud is related to the yaw angle (Yaw) and pitch angle (Pitch), which are expressed by Formula 1 as follows:

[0033] Formula 1

[0034] Among them, the laser radar is configured with a three-dimensional coordinate system XYZ, the position of the data point is (x, y, z), and dist is the distance from the data point to the origin of the three-dimensional coordinate system XYZ.

[0035] There is an installation error between the galvanometer 11 and the angle-expanding lens 12, which results in errors in the yaw angle and / or pitch angle. As can be seen from Formula 1, this makes the position of each data point calculated by the lidar inaccurate. For example, when describing the shape of a rectangular object based on a point cloud with errors, the shape of the object is deformed and is no longer described as a rectangular object. Therefore, the object has a point cloud distortion.

[0036] It can be understood that the angle-expanding lens amplifies the angle of the laser line reflected by the galvanometer before emitting it. When there is an installation error between the galvanometer 11 and the angle-expanding lens 12, the larger the field of view angle, the more severe the distortion of the data point corresponding to the field of view angle, and the smaller the field of view angle, the slighter the distortion of the data point corresponding to the field of view angle. For example, the scanning angle range of the galvanometer is [-30°, 30°]. After being magnified 2 times by the angle-expanding lens, the field of view angle range of the laser radar is [-60°, 60°]. The degree of distortion of the data point corresponding to the -60° field of view angle is greater than the degree of distortion of the data point corresponding to the -59° field of view angle. Similarly, the degree of distortion of the data point corresponding to the 60° field of view angle is greater than the degree of distortion of the data point corresponding to the 59° field of view angle. It can be seen from this that the maximum degree of distortion occurs at the data point corresponding to the edge field of view angle range, for example, the data point corresponding to the -60° field of view angle or the data point corresponding to the 60° field of view angle.

[0037] 3. Construction of the calibration site provided in the embodiment of the present application See also Figure 2 In the embodiment of the present application, a calibration site is built, and a first calibration plate 21, a second calibration plate 22, and a turntable 23 are set in the calibration site. A laser radar 24 is placed on the turntable 23. The turntable 23 drives the laser radar 24 to rotate, changing the posture of the laser radar 24 so that the laser radar 24 emits a laser line to scan the first calibration plate 21 and the second calibration plate 22. Among them, the laser line with a part of the field of view angle can hit the first calibration plate 21 and / or the second calibration plate 22 and is reflected back to the laser radar 24 by the first calibration plate 21 and / or the second calibration plate 22. The laser line with another part of the field of view angle does not hit the first calibration plate 21 and / or the second calibration plate 22 but hits other objects or the ground, and is reflected back to the laser radar 24 by other objects or the ground.

[0038] It can be understood that the embodiment of the present application can control the rotation of the turntable 23, the turntable 23 stops at multiple angle positions, and control the laser radar to scan a frame of point cloud at the corresponding position, so that the laser lines of the laser radar 24 with different field of view angles can all hit the first calibration plate 21 and / or the second calibration plate 22, and be returned to the laser radar by the first calibration plate 21 and / or the second calibration plate 22, thereby realizing the calibration of internal and external parameters of different field of view angles within the field of view angle range of the laser radar.

[0039] 4. Overview of the Implementation of the Embodiments of the Application The overall implementation process of the embodiment of this application is as follows: 4.1) Control the turntable to drive the LiDAR to collect multiple frames of point clouds in different postures; 4.2) Determine candidate extrinsic parameter data for the LiDAR. The candidate extrinsic parameter data includes candidate yaw extrinsic parameters, candidate pitch extrinsic parameters, and candidate roll extrinsic parameters. The candidate extrinsic parameter data is used to represent the current attitude of the LiDAR. 4.3) Obtain target internal parameter data, including target yaw internal parameter, target pitch internal parameter and target roll internal parameter; 4.4) The target internal parameter data is used to update the candidate external parameter data to obtain the target external parameter data, which includes the target yaw external parameter, the target pitch external parameter and the target roll external parameter.

[0040] 4.5) Verify whether the target internal reference data meets the requirements.

[0041] It is understood that the content of 4.1) has been discussed in point ③ and will not be repeated here. The following embodiments of this application will discuss 4.2) to 4.5).

[0042] 5. Determine the candidate external parameter data for LiDAR The candidate extrinsic parameter data includes candidate yaw extrinsic parameters, candidate pitch extrinsic parameters, and candidate roll extrinsic parameters. The embodiments of the present application respectively introduce the determination of candidate yaw extrinsic parameters, candidate pitch extrinsic parameters, and candidate roll extrinsic parameters, as follows: 5.1) Determine candidate yaw extrinsics.

[0043] See also Figure 3 In this embodiment of the present application, the candidate yaw extrinsic parameters are determined through steps S31 to S34, as shown below: Step S31, obtaining true ground data.

[0044] The ground truth data is used to represent the ground truth of the calibration site. The first calibration plate and the second calibration plate are spaced apart and arranged on the calibration site. In the embodiment of the present application, a high-precision laser radar is used to pre-detect the ground of the calibration site to obtain the ground truth data.

[0045] Step S32: determining a first normal vector of the true ground based on the true ground data.

[0046] The first normal vector is perpendicular to the ground plane. The yaw angle (yaw) is the angle at which the LiDAR rotates around an axis perpendicular to the ground plane. The LiDAR's yaw angle at its current position is represented by the angle between the ground plane normal vector detected by the LiDAR and the ground plane normal vector.

[0047] The embodiment of the present application determines a plane equation about the true ground based on the true ground data, and determines the first normal vector of the true ground based on the plane equation of the true ground .

[0048] Step S33: determining a second normal vector of the actual ground based on the point cloud.

[0049] The actual ground is the ground of the calibration site detected by the laser radar to be calibrated, and the second normal vector is the normal vector perpendicular to the actual ground. The embodiment of the present application extracts the actual ground data corresponding to the actual ground from the point cloud, determines the plane equation about the actual ground based on the actual ground data, and determines the second normal vector of the actual ground based on the plane equation of the actual ground. .

[0050] Step S34: determining a first angle between the first normal vector and the second normal vector.

[0051] In the embodiment of the present application, a dot product is performed on the first normal vector and the second normal vector according to Formula 2, thereby obtaining a first angle, as shown below: Formula 2 Among them, the first angle is the candidate yaw extrinsic parameter yaw.

[0052] It can be understood that when the laser radar is configured with a three-dimensional coordinate system XYZ, the X-axis is perpendicular to the exit surface of the laser radar, the Y-axis is perpendicular to the X-axis in the horizontal plane, and the Z-axis is perpendicular to the Y-axis in the vertical plane, the yaw angle (yaw) is the angle at which the laser radar rotates around the Z-axis.

[0053] 5.2) Determine the candidate pitch extrinsic parameters.

[0054] See also Figure 4 In this embodiment of the present application, the candidate yaw extrinsic parameters are determined through steps S41 to S44, as shown below: Step S41, obtaining true value board data.

[0055] The true value plate surface data is used to represent the true value plate surface corresponding to the first calibration plate and the second calibration plate. In the embodiment of the present application, a high-precision laser radar is used to pre-detect the first calibration plate and the second calibration plate to obtain the true value plate surface data.

[0056] Step S42: determining the third normal vector of the true value board surface based on the true value board surface data.

[0057] The third normal vector is perpendicular to the true plate surface. The pitch angle is the angle at which the LiDAR rotates around an axis perpendicular to the first or second calibration plate. The pitch angle of the LiDAR in its current posture can be expressed as the angle between the normal vector of the actual plate surface detected by the LiDAR and the normal vector of the true plate surface.

[0058] The embodiment of the present application determines the plane equation of the true value board based on the true value board data, and determines the third normal vector of the true value board based on the plane equation of the true value board .

[0059] Step S43: determining the fourth normal vector of the actual board surface based on the point cloud.

[0060] The actual plate surface is the plate surface obtained by the laser radar to be calibrated detecting the first calibration plate or the second calibration plate, and the fourth normal vector is the normal vector perpendicular to the actual plate surface. The embodiment of the present application extracts the actual plate surface data corresponding to the actual plate surface from the point cloud, determines the plane equation of the actual plate surface based on the actual plate surface data, and determines the fourth normal vector of the actual plate surface based on the plane equation of the actual plate surface. .

[0061] Step S44: Determine a second angle between the third normal vector and the fourth normal vector.

[0062] In the embodiment of the present application, the third normal vector and the fourth normal vector are dot-multiplied according to Formula 3 to obtain the second angle, as shown below: Formula 2 Among them, the second angle The candidate pitch external parameter pitch.

[0063] It can be understood that when the laser radar is configured with a three-dimensional coordinate system XYZ, the X-axis is perpendicular to the exit surface of the laser radar, the Y-axis is perpendicular to the X-axis in the horizontal plane, and the Z-axis is perpendicular to the Y-axis in the vertical plane, the pitch angle is the angle of rotation of the laser radar around the Y-axis.

[0064] 5.3) Determine the candidate roll external parameters.

[0065] See also Figure 5 In this embodiment of the present application, the candidate rolling external parameters are determined through steps S51 to S57, as shown below: Step S51, obtaining true ground data and true board data.

[0066] Step S52: determining a first normal vector of the true ground based on the true data.

[0067] Step S53: determining the third normal vector of the true value board surface based on the true value board surface data.

[0068] Step S54 , performing a cross product on the first normal vector and the third normal vector to obtain a fifth normal vector.

[0069] Step S55 , determining the second normal vector of the actual ground and the fourth normal vector of the first calibration plate or the second calibration plate based on the point cloud, where the actual ground is the ground of the calibration site detected by the laser radar.

[0070] Step S56: perform a cross product on the second normal vector and the fourth normal vector to obtain a sixth normal vector.

[0071] Step S57: Determine a third angle between the fifth normal vector and the sixth normal vector, where the third angle is a candidate rolling extrinsic parameter.

[0072] In steps S51 to S53, the method of obtaining the true ground data and the true plate surface data, and the method of determining the first normal vector and the third normal vector are all explained above and will not be repeated here.

[0073] In step S54, the fifth normal vector is perpendicular to the plane formed by the first normal vector and the second normal vector. In the embodiment of the present application, the fifth normal vector is obtained according to Formula 3, as shown below: Formula 3 in, is the fifth normal vector.

[0074] In step S55 , the method for obtaining the second normal vector and the fourth normal vector has been discussed above and will not be repeated here.

[0075] In step S56, the sixth normal vector is perpendicular to the plane formed by the second normal vector and the fourth normal vector. In the embodiment of the present application, the sixth normal vector is obtained according to Formula 4, as shown below: Formula 4 in, is the sixth normal vector.

[0076] In step S57, the candidate roll extrinsic parameter can be represented by the angle between the fifth normal vector and the sixth normal vector. In the embodiment of the present application, the candidate roll extrinsic parameter is obtained according to Formula 5, as shown below: Formula 5 in, is the third angle, the third angle Candidate roll external parameter.

[0077] It can be understood that when the laser radar is configured with a three-dimensional coordinate system XYZ, the X-axis is perpendicular to the exit surface of the laser radar, the Y-axis is perpendicular to the X-axis in the horizontal plane, and the Z-axis is perpendicular to the Y-axis in the vertical plane, the roll angle (roll) is the angle of rotation of the laser radar around the X-axis.

[0078] So far, the embodiments of the present application have described the process of determining candidate yaw extrinsic parameters, candidate pitch extrinsic parameters, and candidate roll extrinsic parameters.

[0079] 6. Obtain target internal reference data The target internal parameter data includes a target yaw internal parameter, a target pitch internal parameter, and a target roll internal parameter. The embodiments of the present application respectively introduce the determination of the target yaw internal parameter, the target pitch internal parameter, and the target roll internal parameter, as follows: 6.1) Determine the target yaw internal parameter See also Figure 6 In this embodiment of the present application, the target yaw internal parameter is determined through steps S61 to S62, as shown below: Step S61 , obtaining a multi-frame point cloud obtained by scanning the first calibration plate and the second calibration plate with different postures by the laser radar.

[0080] In some embodiments, a point cloud is obtained by scanning a first calibration plate and a second calibration plate with a laser radar in an arbitrary posture. The laser radar outputs a laser line to scan the calibration plate within the field of view angle range of the posture. The field of view angle range is the angle range that the laser radar can scan. The field of view angle range of the laser radar is [m, n]. Exemplarily, m = -30°, n = 30°, the field of view angle range is [-30°, 30°], and the field of view angle is an angle in [-30°, 30°]. Another exemplary embodiment is that m = 0°, n = 60°, and the field of view angle range is [0°, 60°].

[0081] For example, a point cloud is obtained by scanning a first calibration plate and a second calibration plate using a lidar at a reference pose. The reference pose is the pose when the laser beam at the kth field of view angle of the lidar can hit the first calibration plate or the second calibration plate, where k is not equal to m and not equal to n. For example, m = -30°, n = 30°, the field of view angle range is [-30°, 30°], and k is not equal to -30° and not equal to 30°, such as k = -29° or 0°.

[0082] As mentioned above, when there is an installation error between the galvanometer and the angle-expanding lens, the larger the field of view angle, the more severe the distortion of the data points corresponding to the field of view angle, and the smaller the field of view angle, the slighter the distortion of the data points corresponding to the field of view angle. In order to obtain more accurate target yaw internal parameters, target pitch internal parameters, and target roll internal parameters, in other embodiments, when the laser line of the edge field of view angle hits the first side panel or the second side panel, the embodiment of the present application collects the current point cloud. The edge field of view angle is the minimum field of view angle or the maximum field of view angle in the field of view angle range.

[0083] Specifically, in other embodiments, the point cloud is obtained by scanning the first calibration plate and the second calibration plate by a laser radar at a specified posture. The embodiment of the present application obtains multiple frames of point cloud through steps 611 to 613, as shown below: Step S611, obtaining a point cloud obtained by scanning the first calibration plate and the second calibration plate by the laser radar in a first posture, where the first posture is the posture when the laser line of the mth field of view angle of the laser radar hits the first calibration plate.

[0084] The turntable can drive the LiDAR to change its posture, allowing the LiDAR's laser beams at different field of view angles to strike the first calibration plate. To obtain a point cloud with maximum distortion, the LiDAR scans the first and second calibration plates in the first posture to obtain a point cloud. That is, when the LiDAR's laser beam at the mth field of view angle strikes the first calibration plate, the LiDAR scans the first and second calibration plates to obtain a point cloud (which can be named the left edge point cloud). The left edge point cloud is the point cloud collected when the LiDAR's laser beam at the minimum field of view angle strikes the first calibration plate. The mth field of view angle is the minimum field of view angle in the LiDAR's field of view range. For example, if m is -30°, the mth field of view angle is the -30° field of view angle.

[0085] For example, see Figure 7 The field of view angle range is [-30°, 30°]. When the laser line 71 of the -30° field of view angle of the laser radar hits the first calibration plate 21, the laser radar scans the first calibration plate 21 and the second calibration plate 22 to obtain the left edge point cloud.

[0086] Step S612, obtaining a point cloud obtained by scanning the first calibration plate and the second calibration plate by the laser radar in a second posture, where the second posture is the posture when the laser line of the nth field of view angle of the laser radar hits the second calibration plate.

[0087] To obtain another point cloud frame with maximum distortion, the LiDAR scans the first and second calibration plates in a second posture to obtain a point cloud. Specifically, when the laser beam at the LiDAR's nth field of view angle strikes the second calibration plate, the LiDAR scans the first and second calibration plates to obtain a point cloud (referred to as the right edge point cloud). The right edge point cloud is the point cloud collected when the laser beam at the maximum field of view angle strikes the first calibration plate. The nth field of view angle is the maximum field of view angle within the LiDAR's field of view range. For example, if n is 30°, the nth field of view angle is the 30th field of view angle.

[0088] For example, see Figure 8 The field of view angle range is [-30°, 30°]. When the laser line 72 of the 30° field of view angle of the laser radar hits the second calibration plate 22, the laser radar scans the first calibration plate 21 and the second calibration plate 22 to obtain the right edge point cloud.

[0089] Step S613, obtaining the point cloud obtained by scanning the first calibration plate and the second calibration plate by the laser radar in the third posture, the third posture is the third posture of the laser radar. The posture when the laser line of the field of view angle hits the middle of the first calibration plate and the second calibration plate.

[0090] In order to obtain another frame of point cloud with the minimum distortion, the laser radar scans the first calibration plate and the second calibration plate in the third posture to obtain the point cloud, that is: when the laser radar's first When the laser line of the field of view angle hits the middle of the first calibration plate and the second calibration plate, the lidar scans the first calibration plate and the second calibration plate to obtain a point cloud (which can be named an intermediate point cloud). The intermediate point cloud is the point cloud collected by the lidar when the laser line of the intermediate field of view angle hits the middle of the first calibration plate and the second calibration plate.

[0091] For example, see Figure 9 , the field of view angle range is [-30°, 30°]. When the laser line 73 of the 0° field of view angle of the laser radar hits the middle of the first calibration plate 21 and the second calibration plate 22, the laser radar scans the first calibration plate 21 and the second calibration plate 22 to obtain the intermediate point cloud.

[0092] The embodiment of the present application can obtain accurate and reliable target yaw intrinsic parameters, target pitch intrinsic parameters and target roll intrinsic parameters based on the left edge point cloud, the right edge point cloud and the middle point cloud.

[0093] Step S62: Determine the target yaw intrinsic parameter based on the multi-frame point cloud.

[0094] The target yaw intrinsic parameter is the yaw intrinsic parameter value that enables each frame of the point cloud to obtain a consistent inter-plate distance value. The inter-plate distance value is the distance between the first calibration plate and the second calibration plate. The yaw intrinsic parameter value is the increment of the yaw angle corresponding to the data point in the point cloud. Based on the yaw intrinsic parameter value, the embodiment of the present application modifies the expression of the yaw angle, where the expression of the yaw angle is shown in Formula 6: Formula 6 in, is the yaw internal parameter value, is the candidate yaw extrinsic parameter, The new yaw extrinsic parameter is obtained by updating the candidate yaw extrinsic parameter based on the yaw intrinsic parameter value.

[0095] The embodiment of the present application can affect the position (x, y, z) of each data point in the point cloud by modifying the yaw intrinsic parameter value, thereby updating the point cloud. The embodiment of the present application uses Formula 7 to reflect the influence of the yaw intrinsic parameter value on the position (x, y, z) of the data point, as shown below:

[0096]

[0097] Formula 7

[0098]

[0099]

[0100] Among them, the location ( , , ) is the new position of the data point, is the expansion angle of the new yaw extrinsic parameter after being processed by the expansion lens, is the expanded angle of the new pitch extrinsic parameter after being processed by the angle expansion lens, is the new pitch extrinsic parameter obtained by updating the candidate pitch extrinsic parameter based on the pitch intrinsic parameter value, and dist is the distance from the data point to the origin of the three-dimensional coordinate system of the lidar.

[0101] Combining Formula 6 and Formula 7, we can see that by modifying the yaw internal parameter value , to achieve the purpose of modifying the candidate yaw extrinsic parameters. When the candidate yaw extrinsic parameters are modified, the position (x, y, z) of the data point is recalculated, thereby realizing the update of the point cloud.

[0102] As mentioned above, there are installation errors between the galvanometer and the angle-expanding lens, which results in inconsistent inter-board distances obtained by the laser radar based on detection at different yaw angles. The embodiment of the present application determines the target yaw intrinsic parameters based on multiple frames of point clouds. The target yaw intrinsic parameters can correct the point cloud distortion that appears on the yaw angle due to the installation error, so that the laser radar can obtain consistent inter-board distance values ​​based on each frame of point cloud.

[0103] The embodiment of the present application determines the target yaw internal parameter through steps S621 to S624 as follows: Step S621: configuring multiple yaw intrinsic parameter values ​​for the point cloud in the same frame.

[0104] A same-frame point cloud refers to a point cloud with multiple yaw intrinsic parameter values ​​applied to the same frame. This same-frame point cloud can be a left edge point cloud or a right edge point cloud. This embodiment of the application configures multiple yaw intrinsic parameter values ​​for the same frame point cloud. For example, this embodiment configures a first yaw intrinsic parameter value w1 and a second yaw intrinsic parameter value w2 for the left edge point cloud, where w1 can be 0 and w2 can be t.

[0105] Step S622 : using multiple yaw intrinsic parameter values ​​to update the same-frame point cloud respectively, so as to obtain multiple inter-plate distance values ​​of the same-frame point cloud.

[0106] The embodiment of the present application combines each yaw intrinsic parameter value and updates each data point in the same-frame point cloud using Formula 7, thereby completing the update of the same-frame point cloud. It can be understood that when the first yaw intrinsic parameter value w1=0, the same-frame point cloud remains unchanged.

[0107] The multiple yaw intrinsic parameter values ​​include a first yaw intrinsic parameter value and a second yaw intrinsic parameter value, and the point cloud in the same frame can be a left edge point cloud or a right edge point cloud.

[0108] Please also refer to Figure 10 and Figure 11 In this embodiment of the present application, the first yaw intrinsic parameter value is used to update the left edge point cloud to obtain a first point cloud, and the second yaw intrinsic parameter value is used to update the left edge point cloud to obtain a second point cloud. In this embodiment of the present application, the first yaw intrinsic parameter value is used to update the right edge point cloud to obtain a third point cloud, and the second yaw intrinsic parameter value is used to update the right edge point cloud to obtain a fourth point cloud. In this embodiment of the present application, a first inter-plate distance value d11 is determined based on the first point cloud, a second inter-plate distance value d21 is determined based on the second point cloud, a third inter-plate distance value d12 is determined based on the third point cloud, and a fourth inter-plate distance value d22 is determined based on the fourth point cloud.

[0109] Step S623 : Based on the multiple yaw intrinsic parameter values ​​and the corresponding inter-board distance values ​​of the point cloud in the same frame, a correlation relationship between the yaw intrinsic parameter values ​​and the inter-board distance values ​​corresponding to the point cloud in the same frame is obtained.

[0110] In this embodiment of the present application, a linear fit is performed on multiple yaw intrinsic parameter values ​​and corresponding inter-panel distance values ​​of a point cloud in the same frame to obtain a first fitting line corresponding to the point cloud in the same frame. Specifically, the embodiment of the present application generates a first fitting line L11 based on the first yaw intrinsic parameter value w1 and the first inter-panel distance value d11, and the second yaw intrinsic parameter value w2 and the second inter-panel distance value d21. The embodiment of the present application generates a first fitting line L12 based on the first yaw intrinsic parameter value w1 and the third inter-panel distance value d12, and the second yaw intrinsic parameter value w2 and the fourth inter-panel distance value d22.

[0111] The first fitting line L11 is used to describe the correlation between the yaw intrinsic parameter value and the inter-board distance value of the left edge point cloud under the influence of different yaw intrinsic parameter values. The first fitting line L12 is used to describe the correlation between the yaw intrinsic parameter value and the inter-board distance value of the right edge point cloud under the influence of different yaw intrinsic parameter values.

[0112] The first fitting straight line L11 and the first fitting straight line L12 are straight lines with the yaw internal parameter value as the independent variable and the inter-plate distance value as the dependent variable.

[0113] The first fitting straight line L11 is represented by a first linear function, wherein the calculation process of the first linear function is as follows: construct the first linear function y=k1x+b1 in advance, substitute the first fitting point (w1, d11) and the second fitting point (w2, d21) into the above first linear function y=k1x+b1, and obtain k1 and b1, thereby obtaining the expression of the first linear function.

[0114] The first fitting straight line L12 is represented by a second linear function, wherein the calculation process of the second linear function is as follows: construct the second linear function y=k2x+b2 in advance, substitute the third fitting point (w1, d12) and the fourth fitting point (w2, d22) into the above second linear function y=k2x+b2, and obtain k2 and b2, thereby obtaining the expression of the second linear function.

[0115] Step S624: Determine the target yaw intrinsic parameter based on the correlation relationship between the point clouds of each frame.

[0116] In the embodiment of the present application, the yaw intrinsic parameter value corresponding to the intersection of the first fitting straight line corresponding to each frame point cloud is determined as the target yaw intrinsic parameter. Specifically, the embodiment of the present application determines the yaw intrinsic parameter value corresponding to the intersection of the first fitting straight line L1 and the first fitting straight line L2 as the target yaw intrinsic parameter.

[0117] The target yaw intrinsic parameter ensures that the LiDAR obtains the same distance between the first and second calibration plates at different yaw angles. Therefore, the target yaw intrinsic parameter corrects point cloud distortion caused by installation errors in the yaw direction. Furthermore, the embodiment of the present application relies on only a few frames of point cloud (left and right edge point clouds) to obtain accurate and reliable target yaw intrinsic parameters, making this approach efficient and accurate.

[0118] 6.2) Determine the target pitch internal parameters The embodiment of the present application determines the target pitch intrinsic parameter through the following steps, which are specifically as follows: Determine the target pitch intrinsic parameter based on multi-frame point cloud.

[0119] The target pitch internal parameter is a pitch internal parameter value that can make the first absolute difference between the ground height of the first target point cloud and the ground height of the third target point cloud equal to the second absolute difference between the ground height of the second target point cloud and the ground height of the third target point cloud, and the first field of view corresponding to the first target point cloud and the second field of view corresponding to the second target point cloud are symmetrical about the third field of view corresponding to the third target point cloud.

[0120] For example, the first target point cloud is the point cloud collected when the laser radar scans the first calibration plate and the second calibration plate with a first field of view of [-50°, 10°]. The second target point cloud is the point cloud collected when the laser radar scans the first calibration plate and the second calibration plate with a second field of view of [-10°, 50°]. The third target point cloud is the point cloud collected when the laser radar scans the first calibration plate and the second calibration plate with a third field of view of [-30°, 30°]. The first field of view and the second field of view are symmetrical about the third field of view.

[0121] In some embodiments, the first target point cloud is a left edge point cloud, the second target point cloud is a right edge point cloud, and the third target point cloud is a middle point cloud.

[0122] The pitch intrinsic parameter value is the increment of the pitch angle corresponding to the data point in the point cloud. Based on the pitch intrinsic parameter value, the embodiment of the present application modifies the expression of the pitch angle, wherein the expression of the pitch angle is: ,in, is the pitch internal parameter value, For candidate pitch external parameters, The new pitch extrinsic parameter is obtained by updating the candidate pitch extrinsic parameter based on the pitch intrinsic parameter value.

[0123] Combining Formula 6 and Formula 7, we can see that by modifying the pitch internal parameter value , to achieve the purpose of modifying the candidate pitch extrinsic parameters. When the candidate pitch extrinsic parameters are modified, the position (x, y, z) of the data point is recalculated, thereby realizing the update of the point cloud.

[0124] As mentioned above, there are installation errors between the galvanometer and the angle-expanding lens, which results in inconsistent ground heights detected by the laser radar based on different pitch angles. The embodiment of the present application determines the target pitch internal parameters based on multiple frames of point clouds. The target pitch internal parameters can correct the point cloud distortion caused by the installation error in the pitch angle, so that the laser radar can obtain a consistent ground height based on each frame of point cloud.

[0125] In this embodiment of the present application, the target pitch internal parameter is determined through steps S71 to S74, specifically as follows: Step S71: configure multiple pitch intrinsic parameter values ​​for the point cloud in the same frame.

[0126] In an embodiment of the present application, multiple pitch intrinsic parameter values ​​are configured for the same frame point cloud. For example, in an embodiment of the present application, a first pitch intrinsic parameter value u1 and a second pitch intrinsic parameter value u2 are configured for the left edge point cloud, where u1 can be 0 and u2 can be r.

[0127] Step S72 : using multiple pitch intrinsic parameter values ​​to update the point cloud of the same frame respectively, so as to obtain multiple ground heights of the point cloud of the same frame.

[0128] The embodiment of the present application combines each pitch intrinsic parameter value and updates each data point in the same-frame point cloud using Formula 7, thereby completing the update of the same-frame point cloud. It can be understood that when the first pitch intrinsic parameter value u1=0, the same-frame point cloud remains unchanged.

[0129] The multiple pitch intrinsic parameter values ​​include a first pitch intrinsic parameter value and a second pitch intrinsic parameter value, and the point cloud in the same frame includes a left edge point cloud, a right edge point cloud and a middle point cloud.

[0130] In the embodiment of the present application, the first pitch intrinsic parameter value is used to update the left edge point cloud to obtain the fifth point cloud, and the second pitch intrinsic parameter value is used to update the left edge point cloud to obtain the sixth point cloud.

[0131] In the embodiment of the present application, the first pitch intrinsic parameter value is used to update the right edge point cloud to obtain the seventh point cloud, and the second pitch intrinsic parameter value is used to update the right edge point cloud to obtain the eighth point cloud.

[0132] In the embodiment of the present application, the first pitch intrinsic parameter value is used to update the intermediate point cloud to obtain the ninth point cloud, and the second pitch intrinsic parameter value is used to update the intermediate point cloud to obtain the tenth point cloud.

[0133] The embodiment of the present application determines the ground height z11 based on the fifth point cloud, determines the ground height z21 based on the sixth point cloud, determines the ground height z12 based on the seventh point cloud, determines the ground height z22 based on the eighth point cloud, determines the ground height z13 based on the ninth point cloud, and determines the ground height z13 based on the tenth point cloud.

[0134] Step S73 , based on the multiple pitch intrinsic parameter values ​​of the point cloud in the same frame and the corresponding ground heights, obtain the correlation relationship between the pitch intrinsic parameter values ​​corresponding to the point cloud in the same frame and the ground heights.

[0135] In the embodiment of the present application, a plurality of pitch intrinsic parameter values ​​of the point cloud of the same frame are linearly fitted with the corresponding ground heights to obtain a second fitting straight line corresponding to the point cloud of the same frame.

[0136] In the embodiment of the present application, a second fitting straight line L21 is generated based on the first pitch intrinsic parameter value u1 and the ground height z11 and the second pitch intrinsic parameter value u2 and the ground height z21.

[0137] In the embodiment of the present application, a second fitting straight line L22 is generated based on the first pitch intrinsic parameter value u1 and the ground height z12 and the second pitch intrinsic parameter value u2 and the ground height z22.

[0138] In the embodiment of the present application, a second fitting straight line L23 is generated based on the first pitch intrinsic parameter value u1 and the ground height z13 and the second pitch intrinsic parameter value u2 and the ground height z23.

[0139] The second fitting line L21 is used to describe the relationship between the pitch intrinsic parameter value and the ground height under the influence of different pitch intrinsic parameter values ​​for the left edge point cloud. The second fitting line L22 is used to describe the relationship between the pitch intrinsic parameter value and the ground height under the influence of different pitch intrinsic parameter values ​​for the right edge point cloud. The second fitting line L23 is used to describe the relationship between the pitch intrinsic parameter value and the ground height under the influence of different pitch intrinsic parameter values ​​for the middle point cloud.

[0140] The second fitting straight line L21 , the second fitting straight line L22 and the second fitting straight line L23 are straight lines that take the pitch internal parameter value as the independent variable and the ground height as the dependent variable.

[0141] The second fitting straight line L21 is represented by a third linear function, wherein the calculation process of the third linear function is as follows: construct the third linear function y=k3x+b3 in advance, substitute the fifth fitting point (u1, z11) and the sixth fitting point (u2, z21) into the above third linear function y=k3x+b3, and obtain k3 and b3, thereby obtaining the expression of the third linear function.

[0142] The second fitting straight line L22 is represented by a fourth linear function, wherein the calculation process of the fourth linear function is as follows: construct the fourth linear function y=k4x+b4 in advance, substitute the seventh fitting point (u1, z12) and the eighth fitting point (u2, z22) into the above fourth linear function y=k4x+b4, and obtain k4 and b4, thereby obtaining the expression of the fourth linear function.

[0143] The second fitting straight line L23 is represented by the fifth linear function, where the calculation process of the fifth linear function is as follows: construct the fifth linear function y=k5x+b5 in advance, substitute the ninth fitting point (u1, z13) and the tenth fitting point (u2, z23) into the above fifth linear function y=k5x+b5, and obtain k5 and b5, and then obtain the expression of the fifth linear function.

[0144] Step S74: Determine the target pitch internal parameter based on the correlation relationship corresponding to the point cloud of each frame.

[0145] Each frame point cloud corresponds to a first pitch line, a second pitch line, and a third pitch line. The first pitch line, the second pitch line, and the third pitch line are all second fitting lines. For example, the first pitch line is the second fitting line L21 mentioned above, the second pitch line is the second fitting line L22, and the third pitch line is the second fitting line L23. In this embodiment of the application, through steps S741 to S747, the target pitch internal parameter is determined based on the correlation relationship corresponding to each frame point cloud, as shown below: Step S741: Obtain reference pitch internal parameters.

[0146] Step S742: Determine a first ground height based on the first pitch line and a reference pitch internal parameter.

[0147] Step S743: Determine a second ground height based on the second pitch line and the reference pitch internal parameter.

[0148] Step S744: Determine a third ground height based on the third pitch line and the reference pitch internal parameter.

[0149] Step S745: Calculate a first absolute value of a difference between the first ground height and the second ground height.

[0150] Step S746: Calculate a second absolute value of the difference between the second ground height and the third ground height.

[0151] Step S747 : In response to the first absolute value being equal to the second absolute value, determining the reference pitch intrinsic parameter as the target pitch intrinsic parameter.

[0152] In step S741 , illustratively, the embodiment of the present application sets the reference pitch intrinsic parameter to e.

[0153] In step S742 , illustratively, the reference pitch internal parameter e is substituted into the third linear function y=k3x+b3 of the second fitting line L21 to obtain the first ground height y1 .

[0154] In step S743 , illustratively, the reference pitch internal parameter e is substituted into the fourth linear function y=k4x+b4 of the second fitting line L22 to obtain the second ground height y2 .

[0155] In step S744, illustratively, the reference pitch internal parameter e is substituted into the fifth linear function y=k5x+b5 of the second fitting straight line L23 to obtain the third ground height y3.

[0156] In step S745, for example, the first absolute value of the difference between the first ground height y1 and the second ground height y2 is .

[0157] In step S746, for example, the second absolute value of the difference between the second ground height y2 and the third ground height y3 is .

[0158] In step S747, when the first absolute value The second absolute value is When , it means that when the laser radar observes the ground height at different pitch angles, it obtains the same height result. At this time, the reference pitch internal parameter can correct the point cloud distortion caused by the installation error in the pitch angle direction. Therefore, the embodiment of the application uses the reference pitch internal parameter as the target pitch internal parameter. Not equal to the second absolute value This indicates that when the laser radar observes the ground height at different pitch angles, different height results are obtained. The reference pitch intrinsic parameter at this time cannot correct the point cloud distortion caused by the installation error in the pitch angle direction. Therefore, the embodiment of the present application needs to update the reference pitch intrinsic parameter e and continue to search for the reference pitch intrinsic parameter e that can meet the requirements of step S747.

[0159] 6.3) Determine the target roll internal parameters The embodiment of the present application determines the target roll intrinsic parameter through the following steps, which are specifically as follows: Based on the multi-frame point cloud, the target roll intrinsic parameter is determined.

[0160] The target roll intrinsic parameter is a roll intrinsic parameter value that enables each frame point cloud to obtain a consistent ground height. The roll intrinsic parameter value is the increment of the roll angle corresponding to the data point in the point cloud. This embodiment of the application determines the target roll intrinsic parameter based on multiple frame point clouds through steps S81 to S84 as shown below: Step S81: configure multiple roll intrinsic parameter values ​​for the point cloud in the same frame.

[0161] In an embodiment of the present application, multiple roll intrinsic parameter values ​​are configured for the same frame point cloud. For example, in an embodiment of the present application, a first roll intrinsic parameter value v1 and a second roll intrinsic parameter value v2 are configured for the left edge point cloud, where v1 can be 0 and v2 can be q.

[0162] In step S82 , a plurality of rolling intrinsic parameter values ​​are used to update the point cloud in the same frame respectively, so as to obtain a plurality of ground heights of the point cloud in the same frame.

[0163] The multiple roll intrinsic parameter values ​​include a first roll intrinsic parameter value and a second roll intrinsic parameter value, and the point cloud in the same frame includes a left edge point cloud and a right edge point cloud.

[0164] Please also refer to Figure 12 and Figure 13 In this embodiment of the present application, the first roll intrinsic parameter value is used to update the left edge point cloud to obtain the eleventh point cloud, and the second roll intrinsic parameter value is used to update the left edge point cloud to obtain the twelfth point cloud. In this embodiment of the present application, the first roll intrinsic parameter value is used to update the right edge point cloud to obtain the thirteenth point cloud, and the second roll intrinsic parameter value is used to update the right edge point cloud to obtain the fourteenth point cloud. In this embodiment of the present application, the ground height a11 is determined based on the eleventh point cloud, the ground height a21 is determined based on the twelfth point cloud, the ground height a12 is determined based on the thirteenth point cloud, and the ground height a22 is determined based on the fourteenth point cloud.

[0165] Step S83 , based on multiple roll intrinsic parameter values ​​and corresponding ground heights of the point cloud in the same frame, obtain the correlation relationship between the roll intrinsic parameter values ​​corresponding to the point cloud in the same frame and the ground height.

[0166] This embodiment of the present application performs a linear fit on multiple roll intrinsic parameter values ​​and corresponding ground heights in a point cloud within a frame to obtain a third fitting line corresponding to the point cloud within the frame. Specifically, this embodiment of the present application generates a third fitting line L31 based on the first roll intrinsic parameter value v1 and ground height a11 and the second roll intrinsic parameter value v2 and ground height a21. A third fitting line L32 is generated based on the first roll intrinsic parameter value v1 and ground height a12 and the second roll intrinsic parameter value v2 and ground height a22.

[0167] The third fitting line L31 is used to describe the correlation between the roll intrinsic parameter value and the ground height under the influence of different roll intrinsic parameter values ​​for the left edge point cloud. The third fitting line L32 is used to describe the correlation between the roll intrinsic parameter value and the ground height under the influence of different roll intrinsic parameter values ​​for the right edge point cloud.

[0168] The third fitting straight line L31 and the third fitting straight line L32 are straight lines that take the roll internal parameter value as the independent variable and the ground height as the dependent variable.

[0169] The third fitting straight line L31 is represented by the sixth linear function, wherein the calculation process of the sixth linear function is as follows: the sixth linear function y=k6x+b6 is constructed in advance, and the eleventh fitting point (v1, a11) and the twelfth fitting point (v2, a21) are substituted into the above-mentioned sixth linear function y=k1x+b1 to obtain k6 and b6, and then the expression of the sixth linear function is obtained.

[0170] The third fitting straight line L32 is represented by the seventh linear function, wherein the calculation process of the seventh linear function is as follows: the seventh linear function y=k7x+b7 is constructed in advance, and the thirteenth fitting point (v1, a12) and the fourteenth fitting point (v2, a22) are substituted into the above seventh linear function y=k7x+b7 to obtain k7 and b7, and then the expression of the seventh linear function is obtained.

[0171] Step S84: Determine the target roll internal parameter based on the correlation relationship between the point clouds of each frame.

[0172] In this embodiment of the present application, the roll intrinsic parameter value corresponding to the intersection of the third fitting lines corresponding to each point cloud is determined as the target roll intrinsic parameter. Specifically, in this embodiment of the present application, the roll intrinsic parameter value corresponding to the intersection of the third fitting line L31 and the third fitting line L32 is determined as the target roll intrinsic parameter.

[0173] The target roll intrinsic parameter enables the LiDAR to obtain the same distance results when observing ground height at different roll angles. Therefore, the target roll intrinsic parameter corrects point cloud distortion caused by installation errors in the roll angle direction. Furthermore, the embodiment of the present application only relies on a few frames of point cloud (left and right edge point clouds) to obtain accurate and reliable target roll intrinsic parameters, which is efficient and accurate.

[0174] 7. Use the target internal reference data to update the candidate external reference data to obtain the target external reference data The embodiment of the present application updates the candidate extrinsic parameter data based on the target intrinsic parameter data to obtain the target extrinsic parameter data, where the target extrinsic parameter data includes a target yaw extrinsic parameter, a target pitch extrinsic parameter, and a target roll extrinsic parameter.

[0175] After the operation in the sixth point, the embodiment of the present application has obtained the target intrinsic parameter data, which will align the angle between the galvanometer and the angle-expanding lens with the real physical situation. However, when the laser radar uses the target intrinsic parameter data and the candidate extrinsic parameter data to solve the position of each data point in each frame of the point cloud, point cloud offset will still occur. Therefore, the embodiment of the present application needs to use the target intrinsic parameter data to update the candidate extrinsic parameter data, and recalibrate the candidate yaw extrinsic parameter, candidate pitch extrinsic parameter and candidate roll extrinsic parameter, so as to obtain more accurate target yaw extrinsic parameter, target pitch extrinsic parameter and target roll extrinsic parameter, respectively, so that the point cloud will no longer be offset or distorted.

[0176] The embodiment of the present application adopts the following steps to update the candidate external parameter data, as shown below: subtracting the target yaw internal parameter by a preset multiple of the candidate yaw external parameter to obtain the target yaw external parameter, subtracting the target pitch internal parameter by a preset multiple of the candidate pitch external parameter to obtain the target pitch external parameter, and subtracting the target roll internal parameter by a preset multiple of the candidate roll external parameter to obtain the target roll external parameter.

[0177] The preset magnification is the magnification of the expander lens. For example, the preset magnification is 2, then: roll_new=roll-2*Inter_Roll pitch_new=pitch-2*Inter_Pitch yaw_new=yaw-2*Inter_Yaw Among them, roll_new is the target roll extrinsic parameter, pitch_new is the target pitch extrinsic parameter, yaw_new is the target yaw extrinsic parameter, roll is the candidate roll extrinsic parameter, pitch is the candidate pitch extrinsic parameter, and yaw is the candidate yaw extrinsic parameter.

[0178] 8. Verify whether the target internal reference data meets the requirements The embodiment of the present application writes the target yaw internal parameter, the target pitch internal parameter, and the target roll internal parameter into the laser radar, controls the laser radar to re-collect the point cloud, and obtains the test inter-board distance value and the test ground height respectively in the manner described in the above embodiment. When the test inter-board distance value is less than the first threshold value, and the test ground height is less than the second threshold value, the embodiment of the present application generates a calibration success message and saves the target yaw internal parameter, the target pitch internal parameter, and the target roll internal parameter. When the test inter-board distance value is greater than the first threshold value, or the test ground height is greater than the second threshold value, the embodiment of the present application generates a calibration failure message and re-determines the target yaw internal parameter, the target pitch internal parameter, and the target roll internal parameter.

[0179] In summary, the embodiments of the present application have at least the following technical effects: 1) The embodiment of the present application calibrates the target yaw intrinsic parameter to correct the point cloud distortion caused by installation error on the yaw angle, which is conducive to the laser radar obtaining reliable and accurate point clouds.

[0180] 2) The embodiment of the present application calibrates the target pitch internal parameters to correct the point cloud distortion caused by installation errors in the pitch angle, which is conducive to the laser radar obtaining reliable and accurate point clouds.

[0181] 3) The embodiment of the present application calibrates the target roll internal parameter to correct the point cloud distortion caused by installation error in the roll angle, which is conducive to the laser radar obtaining reliable and accurate point clouds.

[0182] 4) Based on points 1) to 3), the embodiments of the present application can correct the point cloud distortion caused by installation errors in any posture of the laser radar, which is conducive to the laser radar obtaining reliable and accurate point clouds.

[0183] 5) The embodiment of the present application updates the candidate extrinsic parameter data based on the target intrinsic parameter data, thereby obtaining more accurate and reliable target extrinsic parameter data. In this way, the laser radar corrects the point cloud distortion based on the target extrinsic parameter data and obtains a more accurate and reliable point cloud.

[0184] 6) The internal and external parameter calibration method provided in the embodiment of the present application can be applied to lidar, providing the industry with a new idea for calibrating wide-angle lenses in point cloud scenarios with sparse pixels.

[0185] 7) The embodiments of the present application can automatically control the turntable to drive the laser radar to rotate, automatically process the point cloud collected by the laser radar, and automatically calibrate the internal and external parameters. The entire calibration process is an automated process, which can reduce the error of manual calibration and improve the calibration efficiency, accuracy and stability.

[0186] It should be noted that, in each of the above-mentioned embodiments, there is not necessarily a certain order between the above-mentioned steps. A person skilled in the art can understand, based on the description of the embodiments of this application, that in different embodiments, the above-mentioned steps may have different execution orders, that is, they may be executed in parallel, or may be executed interchangeably, etc.

[0187] As another aspect of the present invention, an embodiment of the present invention provides an internal parameter calibration device for a laser radar, wherein the internal parameter calibrator of the laser radar can access the memory and call instructions for execution to complete the internal parameter calibration method of the laser radar described in each of the above embodiments.

[0188] In some embodiments, the internal parameter calibration device of the laser radar can also be constructed by hardware devices. For example, the internal parameter calibration device of the laser radar can be constructed by one or more chips, and the chips can work in coordination with each other to complete the internal parameter calibration method of the laser radar described in the above embodiments. For another example, the internal parameter calibration device of the laser radar can also be constructed by various logic devices, such as a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a single-chip microcomputer, an ARM (Acorn RISC Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these components.

[0189] See also Figure 14 The laser radar internal parameter calibration device 140 includes a yaw internal parameter calibration module 141. The yaw internal parameter calibration module 141 is used to obtain multiple frames of point clouds obtained by the laser radar scanning the first calibration plate and the second calibration plate in different postures, and determine the target yaw internal parameter based on the multiple frames of the point cloud. The target yaw internal parameter is a yaw internal parameter value that can enable the point cloud of each frame to obtain a consistent inter-plate distance value. The yaw internal parameter value is an increment of the yaw angle corresponding to the data point in the point cloud, and the inter-plate distance value is the distance from the first calibration plate to the second calibration plate.

[0190] In some embodiments, the yaw intrinsic parameter calibration module 141 is specifically used to: configure multiple yaw intrinsic parameter values ​​for the same-frame point cloud, use multiple yaw intrinsic parameter values ​​to update the same-frame point cloud respectively to obtain multiple inter-board distance values ​​of the same-frame point cloud, based on the multiple yaw intrinsic parameter values ​​of the same-frame point cloud and the corresponding inter-board distance values, obtain the correlation relationship between the yaw intrinsic parameter value and the inter-board distance value corresponding to the same-frame point cloud, and determine the target yaw intrinsic parameter according to the corresponding correlation relationship of the point cloud in each frame.

[0191] In some embodiments, the yaw intrinsic parameter calibration module 141 is further specifically configured to perform linear fitting on multiple yaw intrinsic parameter values ​​of the same-frame point cloud and corresponding inter-board distance values ​​to obtain a first fitting straight line corresponding to the same-frame point cloud.

[0192] In some embodiments, the yaw intrinsic parameter calibration module 141 is further specifically configured to determine the yaw intrinsic parameter value corresponding to the intersection of the first fitting straight line corresponding to the point cloud of each frame as the target yaw intrinsic parameter.

[0193] Please continue reading Figure 14 The internal parameter calibration device 140 of the laser radar also includes a pitch internal parameter calibration module 142, which is used to determine the target pitch internal parameter based on multiple frames of the point cloud, wherein the target pitch internal parameter is a pitch internal parameter value that can make the first absolute difference between the ground height of the first target point cloud and the ground height of the third target point cloud equal to the second absolute difference between the ground height of the second target point cloud and the ground height of the third target point cloud, the first field of view corresponding to the first target point cloud and the second field of view corresponding to the second target point cloud are symmetrical about the third field of view corresponding to the third target point cloud, and the pitch internal parameter value is the increment of the pitch angle corresponding to the data point in the point cloud.

[0194] In some embodiments, the pitch intrinsic parameter calibration module 142 is specifically used to: configure multiple pitch intrinsic parameter values ​​for the same-frame point cloud, use multiple pitch intrinsic parameter values ​​to update the same-frame point cloud respectively to obtain multiple ground heights of the same-frame point cloud, and based on the multiple pitch intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground heights, obtain the correlation relationship between the pitch intrinsic parameter value corresponding to the same-frame point cloud and the ground height; and determine the target pitch intrinsic parameter according to the corresponding correlation relationship of the point cloud in each frame.

[0195] In some embodiments, the pitch intrinsic parameter calibration module 142 is specifically used to perform linear fitting on multiple pitch intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground height to obtain a second fitting straight line corresponding to the same-frame point cloud.

[0196] In some embodiments, each frame of the point cloud corresponds to a first pitch line, a second pitch line and a third pitch line, and the first pitch line, the second pitch line and the third pitch line are all second fitting lines. The pitch intrinsic parameter calibration module 142 is specifically used to: obtain a reference pitch intrinsic parameter, determine a first ground height based on the first pitch line and the reference pitch intrinsic parameter, determine a second ground height based on the second pitch line and the reference pitch intrinsic parameter, determine a third ground height based on the third pitch line and the reference pitch intrinsic parameter, calculate a first absolute value of the difference between the first ground height and the second ground height, calculate a second absolute value of the difference between the second ground height and the third ground height, and in response to the first absolute value being equal to the second absolute value, determine the reference pitch intrinsic parameter as the target pitch intrinsic parameter.

[0197] In some embodiments, please refer to Figure 14 The internal parameter calibration device 140 of the laser radar also includes a roll internal parameter calibration module 143, which is used to determine the target roll internal parameter based on multiple frames of point clouds, wherein the target roll internal parameter is a roll internal parameter value that can enable the point cloud of each frame to obtain a consistent ground height, and the roll internal parameter value is an increment of the roll angle corresponding to the data point in the point cloud.

[0198] In some embodiments, the roll intrinsic parameter calibration module 143 is specifically used to: configure multiple roll intrinsic parameter values ​​for the same-frame point cloud, use multiple roll intrinsic parameter values ​​to update the same-frame point cloud respectively to obtain multiple ground heights of the same-frame point cloud, and based on the multiple roll intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground heights, obtain the correlation relationship between the roll intrinsic parameter value corresponding to the same-frame point cloud and the ground height; and determine the target roll intrinsic parameter according to the corresponding correlation relationship of the point cloud in each frame.

[0199] In some embodiments, the roll intrinsic parameter calibration module 143 is specifically used to perform linear fitting on multiple roll intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground height to obtain a third fitting straight line corresponding to the same-frame point cloud.

[0200] In some embodiments, the roll intrinsic parameter calibration module 143 is specifically configured to determine the roll intrinsic parameter value corresponding to the intersection point of the third fitting straight line corresponding to each point cloud as the target roll intrinsic parameter.

[0201] In some embodiments, the field of view angle range of the laser radar is [m, n], and the yaw intrinsic parameter calibration module 141 is further specifically used to: obtain the point cloud obtained by the laser radar scanning the first calibration plate and the second calibration plate in a first posture, the first posture is the posture when the laser line of the mth field of view angle of the laser radar hits the first calibration plate, obtain the point cloud obtained by the laser radar scanning the first calibration plate and the second calibration plate in a second posture, the second posture is the posture when the laser line of the nth field of view angle of the laser radar hits the second calibration plate, obtain the point cloud obtained by the laser radar scanning the first calibration plate and the second calibration plate in a third posture, the third posture is the posture of the laser radar. The posture when the laser line of the field of view angle hits the middle of the first calibration plate and the second calibration plate.

[0202] As another aspect of the present invention, the present invention provides a method for calibrating the internal and external parameters of a laser radar. Figure 15 The laser radar's internal and external parameter calibration device 150 includes an external parameter calibration module 151 and an internal parameter calibration module 152. The external parameter calibration module 151 is used to determine candidate external parameter data for the laser radar, wherein the candidate external parameter data includes candidate yaw external parameters, candidate pitch external parameters, and candidate roll external parameters. The internal parameter calibration module 152 is used to obtain target internal parameter data obtained based on the above-mentioned internal parameter calibration method, wherein the target internal parameter data includes target yaw internal parameters, target pitch internal parameters, and target roll internal parameters.

[0203] In some embodiments, the extrinsic parameter calibration module 151 is specifically used to: obtain true ground data, the true ground data is used to represent the true ground of the calibration site, the first calibration plate and the second calibration plate are spaced apart and arranged on the calibration site, determine the first normal vector of the true ground based on the true ground data, determine the second normal vector of the actual ground based on the point cloud, the actual ground is the ground of the calibration site detected by the laser radar, determine the first angle between the first normal vector and the second normal vector, and the first angle is the candidate yaw extrinsic parameter.

[0204] In some embodiments, the extrinsic parameter calibration module 151 is specifically used to: obtain true value panel data, the true value panel data is used to represent the true value panel corresponding to the first calibration plate and the second calibration plate, determine the third normal vector of the true value panel based on the true value panel data, determine the fourth normal vector of the actual panel based on the point cloud, the actual panel is the panel obtained by the laser radar detecting the first calibration plate or the second calibration plate, determine the second angle between the third normal vector and the fourth normal vector, the second angle is the candidate pitch extrinsic parameter.

[0205] In some embodiments, the extrinsic parameter calibration module 151 is specifically used to: obtain true ground data and true plate data, the true ground data is used to represent the true ground of the calibration site, the true plate data is used to represent the true plate corresponding to the first calibration plate and the second calibration plate, determine the first normal vector of the true ground based on the true ground data, determine the third normal vector of the true plate based on the true plate data, cross-product the first normal vector and the third normal vector to obtain a fifth normal vector, determine the second normal vector of the actual ground and the fourth normal vector of the first calibration plate or the second calibration plate based on the point cloud, the actual ground is the ground of the calibration site obtained by detection by the lidar, cross-product the second normal vector and the fourth normal vector to obtain a sixth normal vector, determine a third angle between the fifth normal vector and the sixth normal vector, and the third angle is the candidate roll extrinsic parameter.

[0206] In some embodiments, the extrinsic parameter calibration module 151 is specifically used to update the candidate extrinsic parameter data based on the target intrinsic parameter data to obtain target extrinsic parameter data, where the target extrinsic parameter data includes a target yaw extrinsic parameter, a target pitch extrinsic parameter, and a target roll extrinsic parameter.

[0207] In some embodiments, the external parameter calibration module 151 is specifically used to: subtract the target yaw internal parameter of the candidate yaw external parameter by a preset multiple to obtain a target yaw external parameter, subtract the target pitch internal parameter of the candidate pitch external parameter by a preset multiple to obtain a target pitch external parameter, and subtract the target roll internal parameter of the candidate roll external parameter by a preset multiple to obtain a target roll external parameter.

[0208] It should be noted that the aforementioned internal parameter calibration device for a laser radar or the internal and external parameter calibration device for a laser radar can execute the internal parameter calibration method for a laser radar or the internal and external parameter calibration method for a laser radar provided in the embodiments of this application, and has the corresponding functional modules and beneficial effects of the execution method. For technical details not fully described in the embodiments of the internal parameter calibration device for a laser radar or the internal and external parameter calibration device for a laser radar, please refer to the internal parameter calibration method for a laser radar or the internal and external parameter calibration method for a laser radar provided in the embodiments of this application.

[0209] See also Figure 16 , Figure 16 This is a schematic diagram of the structure of a laser radar provided in an embodiment of the present application. The laser radar 160 includes one or more processors 161 and a memory 162. The memory 162 is connected to the one or more processors 161, for example, via a bus.

[0210] Processor 161 is configured to support the lidar in executing the corresponding functions of the method in the above method embodiment. The processor can be a central processing unit (CPU), a network processor (NP), a hardware chip, or any combination thereof. The hardware chip can be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or any combination thereof. The PLD can be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0211] Memory 162 is used to store program code, etc. Memory can include volatile memory (VM), such as random access memory (RAM); non-volatile memory (NVM), such as read-only memory (ROM), flash memory, a hard disk drive (HDD), or a solid-state drive (SSD); or a combination of the aforementioned types of memory.

[0212] The memory 162 can be used to store non-volatile software programs, non-volatile computer executable programs and modules, such as the program instructions / modules corresponding to the intrinsic parameter calibration method of the laser radar or the internal and external parameter calibration method of the laser radar in the embodiments of the present application. The processor executes the various functional applications and data processing of the intrinsic parameter calibration method of the laser radar or the internal and external parameter calibration method of the laser radar and the internal parameter calibration device of the laser radar or the internal and external parameter calibration device of the laser radar by running the non-volatile software programs, instructions and modules stored in the memory, that is, realizes the functions of the internal parameter calibration method of the laser radar or the internal and external parameter calibration method of the laser radar and the internal parameter calibration device of the laser radar or the internal and external parameter calibration device of the laser radar provided in the above method embodiments.

[0213] The memory may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function. The data storage area may store data created based on the use of the laser radar's internal calibration device or the laser radar's internal and external calibration devices, etc. In some embodiments, the memory may optionally include a memory remotely located relative to the processor, and these remote memories may be connected to the laser radar's internal calibration device or the laser radar's internal and external calibration devices via a network. Examples of the aforementioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0214] The one or more modules are stored in the memory, and when executed by the one or more processors, the internal parameter calibration method of the laser radar or the internal and external parameter calibration method of the laser radar in any of the above method embodiments is executed, for example, the method steps described in the above method embodiments are executed to realize the functions of the modules described in the above device embodiments.

[0215] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a computer, the computer executes the method as described in the above embodiment.

[0216] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing related hardware through a computer program. The program can be stored in a computer-readable storage medium, and when executed, the program can include the processes in the above-described method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0217] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A laser radar internal parameter calibration method, characterized in that: include: Obtaining multi-frame point clouds obtained by scanning the first calibration plate and the second calibration plate with different postures by the laser radar; Based on the point cloud of multiple frames, the target yaw intrinsic parameter is determined, wherein the target yaw intrinsic parameter is a yaw intrinsic parameter value that can enable the point cloud of each frame to obtain a consistent inter-plate distance value, the yaw intrinsic parameter value is the increment of the yaw angle corresponding to the data point in the point cloud, and the inter-plate distance value is the distance from the first calibration plate to the second calibration plate.

2. The method according to claim 1, characterized in that Determining the target yaw intrinsic parameter based on the multiple frames of the point cloud includes: Configure multiple yaw intrinsic parameter values ​​for the same frame point cloud; Using multiple yaw intrinsic parameter values ​​to update the same-frame point cloud respectively to obtain multiple inter-plate distance values ​​of the same-frame point cloud; Based on the multiple yaw intrinsic parameter values ​​and the corresponding inter-board distance values ​​of the same-frame point cloud, obtaining a correlation relationship between the yaw intrinsic parameter values ​​and the inter-board distance values ​​corresponding to the same-frame point cloud; and The target yaw intrinsic parameter is determined according to the correlation relationship corresponding to the point cloud of each frame.

3. The method according to claim 2, characterized in that The obtaining, based on the multiple yaw intrinsic parameter values ​​and the corresponding inter-board distance values ​​of the same-frame point cloud, of the correlation relationship between the yaw intrinsic parameter values ​​and the inter-board distance values ​​corresponding to the same-frame point cloud includes: Linear fitting is performed on multiple yaw intrinsic parameter values ​​of the same-frame point cloud and corresponding inter-plate distance values ​​to obtain a first fitting straight line corresponding to the same-frame point cloud.

4. The method according to claim 3, characterized in that Determining the target yaw intrinsic parameter according to the correlation relationship corresponding to the multiple frame point clouds includes: The yaw intrinsic parameter value corresponding to the intersection point of the first fitting straight line corresponding to the point cloud of each frame is determined as the target yaw intrinsic parameter.

5. The method according to claim 1, wherein Also includes: Based on multiple frames of the point cloud, the target pitch intrinsic parameter is determined, wherein the target pitch intrinsic parameter is a pitch intrinsic parameter value that can make the first absolute difference between the ground height of the first target point cloud and the ground height of the third target point cloud equal to the second absolute difference between the ground height of the second target point cloud and the ground height of the third target point cloud, the first field of view corresponding to the first target point cloud and the second field of view corresponding to the second target point cloud are symmetrical about the third field of view corresponding to the third target point cloud, and the pitch intrinsic parameter value is the increment of the pitch angle corresponding to the data point in the point cloud.

6. The method according to claim 5, characterized in that Determining the target pitch intrinsic parameter based on the multiple frames of the point cloud includes: Configure multiple pitch intrinsic parameter values ​​for the same frame point cloud; Using multiple pitch intrinsic parameter values ​​to update the same-frame point cloud respectively to obtain multiple ground heights of the same-frame point cloud; Based on the multiple pitch intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground heights, obtaining a correlation relationship between the pitch intrinsic parameter values ​​corresponding to the same-frame point cloud and the ground heights; and The target pitch intrinsic parameter is determined according to the correlation relationship corresponding to the point cloud of each frame.

7. The method according to claim 6, characterized in that The obtaining, based on the multiple pitch intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground heights, a correlation relationship between the pitch intrinsic parameter values ​​corresponding to the same-frame point cloud and the ground heights includes: Linear fitting is performed on multiple pitch intrinsic parameter values ​​of the same-frame point cloud and corresponding ground heights to obtain a second fitting straight line corresponding to the same-frame point cloud.

8. The method according to claim 7, characterized in that The point cloud of each frame corresponds to a first pitch line, a second pitch line, and a third pitch line, and the first pitch line, the second pitch line, and the third pitch line are all second fitting lines. The target pitch intrinsic parameter is determined according to the correlation relationship corresponding to the point cloud of each frame, including: Get the reference pitch internal parameter; determining a first ground height based on the first pitch line and the reference pitch intrinsic parameter; determining a second ground height based on the second pitch line and the reference pitch intrinsic parameter; determining a third ground height based on the third pitch line and the reference pitch intrinsic parameter; Calculating a first absolute value of a difference between the first ground height and the second ground height; Calculating a second absolute value of a difference between the second ground height and the third ground height; In response to the first absolute value being equal to the second absolute value, the reference pitch intrinsic parameter is determined to be a target pitch intrinsic parameter.

9. The method according to claim 1, characterized in that Also includes: Based on the point clouds of multiple frames, a target roll intrinsic parameter is determined, wherein the target roll intrinsic parameter is a roll intrinsic parameter value that enables the point clouds of each frame to obtain a consistent ground height, and the roll intrinsic parameter value is an increment of the roll angle corresponding to the data points in the point cloud.

10. The method according to claim 9, characterized in that Determining the target roll intrinsic parameter based on the point cloud of multiple frames includes: Configure multiple roll intrinsic parameter values ​​for the same frame point cloud; Using multiple roll intrinsic parameter values ​​to update the same-frame point cloud respectively to obtain multiple ground heights of the same-frame point cloud; Based on the multiple roll intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground heights, obtaining a correlation relationship between the roll intrinsic parameter values ​​corresponding to the same-frame point cloud and the ground heights; and The target roll intrinsic parameter is determined according to the correlation relationship corresponding to the point cloud of each frame.

11. The method according to claim 10, characterized in that The obtaining, based on the multiple roll intrinsic parameter values ​​of the same-frame point cloud and the corresponding ground heights, a correlation relationship between the roll intrinsic parameter values ​​corresponding to the same-frame point cloud and the ground heights includes: Linear fitting is performed on multiple roll intrinsic parameter values ​​of the same-frame point cloud and corresponding ground heights to obtain a third fitting straight line corresponding to the same-frame point cloud.

12. The method according to claim 11, characterized in that Determining the target roll intrinsic parameter according to the correlation relationship corresponding to the point cloud of each frame includes: The roll intrinsic parameter value corresponding to the intersection point of the third fitting straight line corresponding to each point cloud is determined as the target roll intrinsic parameter.

13. The method according to any one of claims 1 to 12, characterized in that The field of view angle range of the laser radar is [m, n]. The multi-frame point cloud obtained by scanning the first calibration plate and the second calibration plate with different postures by the laser radar includes: Obtaining a point cloud obtained by scanning a first calibration plate and a second calibration plate by the laser radar in a first posture, where the first posture is the posture when a laser line of an mth field of view angle of the laser radar hits the first calibration plate; Obtaining a point cloud obtained by scanning the first calibration plate and the second calibration plate by the laser radar in a second posture, where the second posture is the posture when the laser line of the laser radar at the nth field of view angle hits the second calibration plate; Obtain a point cloud obtained by scanning the first calibration plate and the second calibration plate by the laser radar in a third posture, wherein the third posture is the first The posture when the laser line of the field of view angle hits the middle of the first calibration plate and the second calibration plate.

14. A method for calibrating internal and external parameters of a laser radar, characterized in that: include: Determining candidate extrinsic parameter data of the laser radar, the candidate extrinsic parameter data including candidate yaw extrinsic parameters, candidate pitch extrinsic parameters, and candidate roll extrinsic parameters; Target internal parameter data obtained based on the internal parameter calibration method according to claims 1 to 13 is acquired, wherein the target internal parameter data includes a target yaw internal parameter, a target pitch internal parameter, and a target roll internal parameter.

15. The method according to claim 14, characterized in that The candidate extrinsic parameter data includes candidate yaw extrinsic parameters, and determining the candidate extrinsic parameter data of the laser radar includes: Acquire true ground data, where the true ground data is used to represent the true ground of a calibration site, where the first calibration plate and the second calibration plate are spaced apart and arranged on the calibration site; Determine a first normal vector of the ground truth based on the ground truth data; Determine a second normal vector of an actual ground surface based on the point cloud, where the actual ground surface is the ground surface of the calibration location detected by the laser radar; A first angle between the first normal vector and the second normal vector is determined, where the first angle is the candidate yaw extrinsic parameter.

16. The method according to claim 14, characterized in that The candidate extrinsic parameter data includes candidate pitch extrinsic parameters, and determining the candidate extrinsic parameter data of the laser radar includes: Acquire true value board surface data, where the true value board surface data is used to represent the true value board surface corresponding to the first calibration board and the second calibration board; Determine a third normal vector of the true value board surface based on the true value board surface data; determining a fourth normal vector of an actual plate surface based on the point cloud, where the actual plate surface is a plate surface obtained by detecting the first calibration plate or the second calibration plate by the laser radar; A second angle between the third normal vector and the fourth normal vector is determined, where the second angle is the candidate pitch extrinsic parameter.

17. The method according to claim 14, characterized in that The candidate extrinsic parameter data includes candidate roll extrinsic parameters, and determining the candidate extrinsic parameter data of the laser radar includes: Acquire true ground data and true plate surface data, wherein the true ground data is used to represent the true ground of the calibration site, and the true plate surface data is used to represent the true plate surface corresponding to the first calibration plate and the second calibration plate; Determine a first normal vector of the ground truth based on the ground truth data; Determine a third normal vector of the true value board surface based on the true value board surface data; Performing a cross product of the first normal vector and the third normal vector to obtain a fifth normal vector; Determining a second normal vector of an actual ground surface and a fourth normal vector of the first calibration plate or the second calibration plate based on the point cloud, wherein the actual ground surface is the ground surface of the calibration location detected by the laser radar; Performing a cross product of the second normal vector and the fourth normal vector to obtain a sixth normal vector; A third angle between the fifth normal vector and the sixth normal vector is determined, where the third angle is the candidate roll extrinsic parameter.

18. The method according to claim 14, characterized in that Also includes: The candidate extrinsic parameter data is updated based on the target intrinsic parameter data to obtain target extrinsic parameter data, where the target extrinsic parameter data includes a target yaw extrinsic parameter, a target pitch extrinsic parameter, and a target roll extrinsic parameter.

19. The method according to claim 18, characterized in that The updating of the candidate external reference data based on the target internal reference data to obtain target external reference data includes: Subtracting a preset multiple of the candidate yaw external parameter from the target yaw internal parameter to obtain the target yaw external parameter; Subtracting a preset multiple of the candidate pitch external parameter from the target pitch internal parameter to obtain the target pitch external parameter; The candidate roll external parameter is subtracted from a target roll internal parameter having a preset multiple to obtain a target roll external parameter.

20. A laser radar, characterized in that: It includes a memory and a processor, the memory is connected to the processor, and the processor is used to execute one or more computer programs stored in the memory. When the processor executes the one or more computer programs, the laser radar implements the internal parameter calibration method of the laser radar as described in any one of claims 1 to 13 or the internal and external parameter calibration method of the laser radar as described in any one of claims 14 to 19.

21. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which includes program instructions. When the program instructions are executed by the processor, the processor executes the internal parameter calibration method of the laser radar as described in any one of claims 1 to 13 or the internal and external parameter calibration method of the laser radar as described in any one of claims 14 to 19.

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