External parameter calibration method, device and electronic equipment for vehicle-mounted multi-laser radar

Abstract

The present invention provides an external parameter calibration method, device and electronic equipment for vehicle-mounted multi-laser radars, including: obtaining point cloud data respectively from multiple laser radars on vehicles in a calibration site; obtaining the rotation angle and position offset of each of the laser radars based on the obtained point cloud data; wherein the position offset is the difference between the coordinate value of the center point of the marker obtained from the point cloud data representing the marker and the actual coordinate value of the center point; the point cloud data representing the marker is obtained by segmenting the point cloud data based on the markers with regular shapes and reflective properties that are fixedly arranged in the calibration site. The method is used to solve the defects of low calibration accuracy and efficiency in the external parameter calibration of multi-laser radars in the prior art, and realize the rapid and accurate calibration of the external parameters of multi-laser radars.

Description

Technical Field

[0001] The present invention relates to the technical field of autonomous driving vehicle production, and in particular to an external parameter calibration method, device and electronic equipment for a vehicle-mounted multi-laser radar. Background Art

[0002] As the development, application and commercialization of autonomous driving technology continues to accelerate, various car companies have increased their investment in the development of autonomous driving technology. Autonomous driving vehicles integrate multiple sensor devices such as laser radar, camera, millimeter wave radar, ultrasonic radar, and inertial measurement unit to perceive the surrounding environment information. Laser radar can collect three-dimensional point cloud information of the surrounding environment, and then accurately measure the target position (distance and angle), motion state (speed, vibration and posture) and shape, that is, it can reliably detect obstacles, and thus plays an important role in autonomous driving technology. However, a single laser radar is difficult to meet the coverage requirements of vehicle perception, so multiple laser radars must be configured on the autonomous driving vehicle, and the corresponding is the calibration between multiple laser radars. The quality of the external parameter calibration between multiple laser radars before the autonomous driving vehicle leaves the factory directly affects the safety and reliability of the vehicle during use.

[0003] At present, before leaving the factory, autonomous driving vehicles mainly use two methods to calibrate the external parameters of the LiDAR on the vehicle: manual calibration or automatic calibration. However, manual calibration mainly relies on the experience and technology of technicians, which is time-consuming and labor-intensive, and has low accuracy. Automatic calibration generally requires a calibration site with a specific layout, or the use of special calibration objects. The calibration method using a calibration site with a specific layout has a more complex layout of markers and a higher algorithm difficulty. The calibration method using special calibration objects requires the calibration objects to be accurately placed at the set position, and often requires the position of the markers to be constantly moved, which can easily result in low calibration accuracy, and generally cannot complete the calibration of more than two LiDARs at the same time, resulting in low calibration efficiency. Summary of the invention

[0004] The present invention provides a method, device and electronic equipment for calibrating the external parameters of a vehicle-mounted multi-laser radar, so as to solve the defects of low calibration accuracy and efficiency during the external parameter calibration of the multi-laser radar in the prior art, and realize fast and accurate calibration of the external parameters of the multi-laser radar.

[0005] The present invention provides an external parameter calibration method for a vehicle-mounted multi-laser radar, comprising:

[0006] Point cloud data is obtained by multiple laser radars on vehicles in the calibration site;

[0007] Obtaining the rotation angle and position offset of each of the laser radars based on the acquired point cloud data;

[0008] The position offset is the difference between the coordinate value of the center point of the marker obtained from the point cloud data representing the marker and the actual coordinate value of the center point;

[0009] The point cloud data representing the markers are obtained by segmenting the point cloud data based on the markers of regular shapes with reflective properties that are fixedly arranged in the calibration site.

[0010] According to a method for calibrating external parameters of a vehicle-mounted multi-lidar provided by the present invention, before the multiple laser radars on the vehicle in the calibration site respectively acquire point cloud data, the method further includes:

[0011] The vehicle is driven into a fixed position in a calibration field consisting of a flat ground plane, and a front plane, a left plane, and a right plane which are respectively fixedly arranged perpendicularly to the ground plane.

[0012] According to an external parameter calibration method for a vehicle-mounted multi-laser radar provided by the present invention, a vehicle is driven into a fixed position in the calibration site, specifically comprising:

[0013] The vehicle is adjusted to the vehicle fixing position marked on the ground plane, and the vehicle body is kept parallel to the left plane and the right plane respectively, and the vehicle direction is perpendicular to the front plane.

[0014] According to an external parameter calibration method for a vehicle-mounted multi-laser radar provided by the present invention, the actual coordinate value of the center point is the coordinate value of the center point of the marker in the vehicle coordinate system;

[0015] The coordinate value of the center point of the marker in the vehicle coordinate system is obtained in the vehicle coordinate system by driving the vehicle into the calibration site so that the origin of the vehicle's coordinate system coincides with the origin of the coordinate system preset in the calibration site.

[0016] According to an external parameter calibration method for a vehicle-mounted multi-laser radar provided by the present invention, the point cloud data representing the marker is obtained by segmenting the point cloud data based on the markers of regular shapes with reflective characteristics fixedly arranged in the calibration site, and specifically includes:

[0017] Based on the regularly shaped markers with reflective properties respectively arranged at the geometric centers of the front plane, the left plane and the right plane, it is determined whether the signal strength of each point cloud in the point cloud data exceeds a preset threshold, and the point cloud with a signal strength exceeding the preset threshold is segmented from the corresponding point cloud data.

[0018] According to a method for calibrating external parameters of a vehicle-mounted multi-laser radar provided by the present invention, obtaining the rotation angle and position offset of each of the laser radars based on the acquired point cloud data specifically includes:

[0019] Selecting part of the point cloud from the point cloud data corresponding to the ground plane to obtain the normal vector of the ground plane, and obtaining the roll angle and pitch angle of each of the laser radars according to the normal vector of the ground plane and the normal vector of the ideal ground plane;

[0020] The plane normal vectors of the front plane, the left plane and the right plane are obtained from the segmented point cloud data, and the yaw angle of the forward laser radar located at the front side of the vehicle is obtained according to the plane normal vector and the ideal front plane normal vector, and the yaw angles of the side laser radars located at the left and right sides of the vehicle are obtained according to the plane normal vector and the ideal side plane normal vector;

[0021] According to the outer points corresponding to each of the markers in the segmented point cloud data, the center point coordinate value of each of the markers is obtained, and the position offset of each of the laser radars is obtained by calculating the difference between the coordinate value of each center point and the actual coordinate value of the corresponding marker center point.

[0022] The present invention also provides an external parameter calibration device for a vehicle-mounted multi-laser radar, comprising:

[0023] A point cloud acquisition module is used to obtain point cloud data from multiple laser radars on vehicles in the calibration site;

[0024] A calculation module, used to obtain the rotation angle and position offset of each of the laser radars based on the acquired point cloud data;

[0025] The position offset is the difference between the coordinate value of the center point of the marker obtained from the point cloud data representing the marker and the actual coordinate value of the center point;

[0026] The point cloud data representing the markers are obtained by segmenting the point cloud data based on the markers of regular shapes with reflective properties that are fixedly arranged in the calibration site.

[0027] According to the present invention, an external parameter calibration device for a vehicle-mounted multi-laser radar further includes:

[0028] A driving module, used for driving the vehicle into a calibration field consisting of a flat ground plane, and a front plane, a left plane, and a right plane respectively fixedly arranged perpendicularly to the ground plane;

[0029] The adjustment module is used to adjust the vehicle to the vehicle fixing position marked on the ground plane, and keep the vehicle body parallel to the left plane and the right plane respectively, and the vehicle direction is perpendicular to the front plane.

[0030] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes, the steps of the external parameter calibration method of any of the above-mentioned vehicle-mounted multi-laser radars are implemented.

[0031] The present invention also provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the external parameter calibration method of any of the above-mentioned vehicle-mounted multi-laser radars.

[0032] The present invention provides an external parameter calibration method, device and electronic equipment for a vehicle-mounted multi-lidar. By arranging markers with reflective properties and regular shapes in the calibration site, the point cloud corresponding to the marker can be accurately and quickly segmented from the point cloud data acquired by the lidar. The regular shape of the marker can be used to conveniently obtain the coordinate value of the point cloud corresponding to the center point of the marker, and then the position offset of the lidar can be obtained using the coordinates of the center point of the marker, thereby improving the calibration accuracy and efficiency of the multi-lidar using the point cloud. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 This is one of the flow charts of an external parameter calibration method for a vehicle-mounted multi-laser radar provided by the present invention;

[0035] Figure 2 This is the second flow chart of the external parameter calibration method of a vehicle-mounted multi-laser radar provided by the present invention;

[0036] Figure 3 It is a structural schematic diagram of the calibration site provided by the present invention;

[0037] Figure 4 It is a structural schematic diagram of the external parameter calibration device of the vehicle-mounted multi-laser radar provided by the present invention;

[0038] Figure 5 is a schematic diagram of the structure of an electronic device provided by the present invention;

[0039] Reference numerals:

[0040] 1: ground plane; 2: front plane; 3: left plane;

[0041] 4: right plane; 5: vehicle fixing position; 6: marker. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Combine the following Figures 1 to 3 The present invention describes an external parameter calibration method of a vehicle-mounted multi-laser radar, such as Figure 1 As shown, the method comprises the following steps:

[0044] 101. Point cloud data are obtained respectively by multiple laser radars on vehicles in the calibration site;

[0045] It should be noted that before an autonomous driving vehicle leaves the factory, the multiple laser radars configured on the vehicle must be calibrated with external parameters so that the surrounding environment can be accurately identified during subsequent driving. Therefore, it is necessary to calibrate the external parameters of the laser radar of each autonomous driving vehicle. Specifically, in the external parameter calibration process, it is first necessary to obtain the point cloud data obtained by scanning the surrounding coverage range of each laser radar on the vehicle. The general way to obtain the point cloud data is to connect each laser radar to a PC separately, and then obtain the point cloud data scanned by the laser radar through the PC and display it on the PC.

[0046] 102. Obtaining a rotation angle and a position offset of each of the laser radars based on the acquired point cloud data;

[0047] It should be noted that in the point cloud data scanned by the laser radar, the point cloud of the marker with reflective characteristics will be significantly different from the point cloud of the ordinary environment. Therefore, when the marker with reflective characteristics is arranged in the calibration site, it will be easier and more accurate to segment the point cloud of the marker from the point cloud data scanned by the laser radar. At the same time, the external parameter calibration of the corresponding laser radar includes the calculation of the rotation angle and the position offset. In the calculation of the position offset, the setting of the marker with regular shape can facilitate the rapid determination of the center point coordinates corresponding to the marker in the segmented point cloud, and the fixed arrangement of the marker in the calibration site also makes it easy to know the actual coordinate value of the center point of the marker, and then it is easy to obtain the accurate offset of the laser radar according to the center point coordinates of the marker in the segmented point cloud data and the actual coordinates of the center point of the marker. That is, by setting the marker with regular shape, the algorithm difficulty of the external parameter calibration of multiple laser radars is greatly reduced, making the calibration accurate and efficient.

[0048] Specifically, the regular-shaped marker with reflective properties can be directly set in the calibration site through reflective materials, or objects made of reflective materials can be arranged in the calibration site. There is no limitation here. At the same time, the shape of the marker can be any regular shape such as circle, square, rectangle, etc. Among them, considering the difficulty of the algorithm during calculation, circle is preferred.

[0049] It can be understood that the structure of the calibration site and the position of the vehicle in the calibration site directly affect the efficiency and accuracy of the laser radar external parameter calibration. Based on this, in one embodiment of the present invention, a calibration site is specifically designed, that is, before multiple laser radars on the vehicle in the calibration site respectively acquire point cloud data, the vehicle is driven into a fixed position in the calibration site consisting of a flat ground plane, and a front plane, a left plane, and a right plane that are respectively fixedly arranged perpendicular to the ground plane.

[0050] It should be noted that the calibration site is composed of the ground plane of the platform and the front plane, left plane and right plane which are respectively fixedly arranged perpendicular to the ground plane. It is worth noting that the calibration site does not require a top surface and a rear plane, that is, it is a non-closed calibration site. Therefore, compared with a closed calibration site, the calibration site of the present invention is more convenient for vehicles to enter and exit, thereby improving the efficiency of calibration.

[0051] Furthermore, the position of the vehicle in the calibration site also has a direct impact on the accuracy of the calibration. Therefore, in order to further improve the calibration accuracy of the multi-lidar, in one embodiment of the present invention, the vehicle is driven into a fixed position in the calibration site, which is specifically defined as adjusting the vehicle to the vehicle fixed position marked on the ground plane, and keeping the vehicle body parallel to the left plane and the right plane respectively, and the vehicle direction is perpendicular to the front plane.

[0052] That is Figure 2 As shown, the external parameter calibration method of a vehicle-mounted multi-laser radar of the present invention further includes the following steps:

[0053] 201. Drive the vehicle into a calibration site consisting of a flat ground plane, and a front plane, a left plane, and a right plane respectively fixedly arranged perpendicularly to the ground plane;

[0054] 202. Adjust the vehicle to the vehicle fixing position marked on the ground plane, and keep the vehicle body parallel to the left plane and the right plane respectively, and the vehicle direction is perpendicular to the front plane;

[0055] 203. Point cloud data are obtained respectively by multiple laser radars on vehicles in the calibration site;

[0056] 204. Obtain the rotation angle and position offset of each of the laser radars based on the acquired point cloud data.

[0057] It should be noted that if the vehicle is driven into Figure 3 The semi-enclosed rectangular venue shown is composed of a flat ground plane 1, and a front plane 2, a left plane 3 and a right plane 4 which are respectively fixedly arranged perpendicular to the ground plane 1. The venue can facilitate the entry and exit of vehicles. When the vehicle is adjusted to the vehicle fixing position 5 marked on the ground plane 1, and the body of the vehicle is parallel to the left and right planes of the venue, and the direction of the vehicle is perpendicular to the front plane 2, the vehicle is in a fixed and standard position in the venue. For the marker 6 fixedly arranged in the calibration venue, the relative relationship between the point cloud data obtained by the laser radar and the marker 6 in the calibration venue is fixed, thereby realizing multi-laser radar external parameter calibration based on a fixed environment, which can further improve the efficiency and accuracy of vehicle factory calibration.

[0058] Specifically, the calibration site can be a fixed semi-enclosed house made of building materials such as concrete, or it can be spliced ​​by a plate structure. Of course, it can also be constructed in other ways as long as it can form a fixed environmental scene, which is not limited here.

[0059] In another embodiment of the present invention, it is specifically described that the actual coordinate value of the center point of the marker used to obtain the position offset of each of the laser radars is the coordinate value of the center point of the marker in the vehicle coordinate system;

[0060] At the same time, the coordinate value of the center point of the marker in the vehicle coordinate system is obtained in the vehicle coordinate system by driving the vehicle into the calibration site so that the origin of the vehicle's coordinate system coincides with the origin of the coordinate system preset in the calibration site.

[0061] It should be noted that in order to obtain the position offset of each laser radar, the coordinates of the marker must first be unified to the vehicle coordinate system. Therefore, the actual coordinate value of the center point of the marker is the coordinate value of the center point of the marker in the vehicle coordinate system. The method of unifying the coordinate system is to make the origin of the vehicle's coordinate system coincide with the origin of the coordinate system preset in the calibration site after the vehicle enters the calibration site.

[0062] Specifically, for example, the actual coordinate value of the center point of the marker can be obtained by measuring after the vehicle enters the calibration site and drives to the vehicle fixed position marked on the ground plane, while keeping the vehicle body parallel to the left plane and the right plane respectively, and the vehicle direction is perpendicular to the front plane; it can also be obtained by making the vehicle drive into a fixed position in the calibration site, making the marked point of the vehicle coordinate system coincide with the marked point in the preset calibration site, and then using the fixed geometric relationship of the calibration site to obtain the actual coordinate value.

[0063] In another embodiment of the present invention, a method for segmenting point cloud data corresponding to the marker from point cloud data is further described, specifically comprising:

[0064] Based on the regularly shaped markers with reflective properties respectively arranged at the geometric centers of the front plane, the left plane and the right plane, it is determined whether the signal strength of each point cloud in the point cloud data exceeds a preset threshold, and the point cloud with a signal strength exceeding the preset threshold is segmented from the corresponding point cloud data.

[0065] It should be noted that arranging each marker at the geometric center of the front plane, left plane and right plane of the calibration site makes the coordinates of the center point of the marker easier to obtain and more accurate, which has a good effect on further improving the efficiency and accuracy of the external parameter calibration of multiple laser radars.

[0066] It can be understood that when a marker with reflective properties is set up and the laser radar scans the marker, the signal strength of the point cloud obtained will be significantly greater than the signal strength of the point cloud obtained under normal conditions due to the reflective characteristics. Therefore, the point cloud of the marker can be easily extracted by utilizing the difference in point cloud signal strength in the point cloud data obtained by the laser radar.

[0067] More specifically, during the calculation process, the point cloud representing the marker can be segmented by pre-setting a threshold, that is, the point cloud satisfying T>t is marked as the point cloud corresponding to the marker, where T represents the signal strength value of each point cloud and t represents the set threshold.

[0068] In another embodiment of the present invention, a specific method for calibrating the external parameters of the laser radar using the point cloud data obtained by the laser radar is further described, and the method specifically includes:

[0069] Selecting part of the point cloud from the point cloud data corresponding to the ground plane to obtain the normal vector of the ground plane, and obtaining the roll angle and pitch angle of each of the laser radars according to the normal vector of the ground plane and the normal vector of the ideal ground plane;

[0070] The plane normal vectors of the front plane, the left plane and the right plane are obtained from the segmented point cloud data, and the yaw angle of the forward laser radar located at the front side of the vehicle is obtained according to the plane normal vector and the ideal front plane normal vector, and the yaw angles of the side laser radars located at the left and right sides of the vehicle are obtained according to the plane normal vector and the ideal side plane normal vector;

[0071] According to the outer points corresponding to each of the markers in the segmented point cloud data, the center point coordinate value of each of the markers is obtained, and the position offset of each of the laser radars is obtained by calculating the difference between the coordinate value of each center point and the actual coordinate value of the corresponding marker center point.

[0072] It should be noted that the external parameter calibration of the laser radar includes the calculation of the rotation angle composed of the roll angle, the pitch angle and the yaw angle, and the calculation of the position offset representing the position offset of the laser radar.

[0073] Specifically, in the calculation of the roll angle and pitch angle of the laser radar, they are mainly calculated by the point cloud data corresponding to the ground plane, for example, by applying the calculation method of the normal vector:

[0074] Select some point clouds from the point cloud data corresponding to the ground plane and calculate the plane equation of the ground plane:

[0075] a*x+b*y+c*z+d=0 Formula 1;

[0076] Among them, x, y, and z represent the coordinate values ​​of each point cloud in their respective lidars, and the coordinate system here is a right-handed coordinate system.

[0077] By solving the four values ​​of parameters a, b, c, and d through formula 1, the normal vector of the ground plane is:

[0078] v g =(a / d,b / d,c / d) Formula 2;

[0079] By finding the normal vector v of the ground plane g The roll angle and pitch angle of each lidar are calculated by the dot product and cross product with the ideal ground plane normal vector (0,0,1).

[0080] In the calculation of the yaw angle of the laser radar, it is mainly calculated by the point cloud data representing each marker that is segmented. Therefore, further, on the basis of calculating the roll angle roll and pitch angle pitch of each laser radar, the yaw angle is calculated using the point cloud data representing each marker segmented from the point cloud data. For example, the calculation method of the normal vector is applied:

[0081] The plane equation of the plane where each marker is located is calculated using the segmented point cloud data:

[0082] e*x+f*y+g*z+h=0 Formula 3;

[0083] Among them, x, y, and z represent the coordinate values ​​of each point cloud in their respective lidars, and the coordinate system here is a right-handed coordinate system.

[0084] By solving the four values ​​of parameters e, f, g, and h through formula 3, the normal vector of the plane where the marker is located is:

[0085] n=(e / h,f / h,g / h) Formula 2;

[0086] The yaw angle yaw of the forward laser radar is calculated by taking the dot product and cross product of the normal vector n and the ideal front plane normal vector (1,0,0) f ; Use the dot product and cross product of the normal vector n and the ideal side plane normal vector (0,1,0) to calculate the yaw angle yaw of the left and right side lidars c .

[0087] Furthermore, the position offset of the laser radar can be obtained by the offset between the position coordinates of the point cloud of the marker obtained by the laser radar and the actual coordinates of the marker. It can be understood that the point cloud of the center of the marker is obviously more accurate than the point cloud of the edge of the marker. Therefore, in the present invention, based on the fixed geometric relationship between the marker and the calibration site, the position offset of each laser radar is obtained by calculating the difference between the coordinates of the center point of the marker obtained from the point cloud data and the actual coordinates of the center point of the marker. For example, the specific calculation process can be:

[0088] The outermost point cloud representing the point cloud data of the marker obtained by segmentation is used to obtain the coordinates of the center point corresponding to the marker using the least squares method ( x ,O y ,O z ), and the actual coordinates of the center point of each marker are subtracted, and the difference (Δx, Δy, Δz) obtained is the position offset value of each lidar.

[0089] The following is a description of an external parameter calibration device for a vehicle-mounted multi-laser radar provided by the present invention. The external parameter calibration device for a vehicle-mounted multi-laser radar described below and the external parameter calibration method for a vehicle-mounted multi-laser radar described above can be referenced to each other.

[0090] like Figure 4 As shown, the present invention provides an external parameter calibration device for a vehicle-mounted multi-laser radar, including a point cloud acquisition module 410 and a calculation module 420; wherein,

[0091] The point cloud acquisition module 410 is used to respectively acquire point cloud data from multiple laser radars on vehicles in the calibration site;

[0092] The calculation module 420 is used to obtain the rotation angle and position offset of each of the laser radars based on the acquired point cloud data;

[0093] The position offset is the difference between the coordinate value of the center point of the marker obtained from the point cloud data representing the marker and the actual coordinate value of the center point;

[0094] The point cloud data representing the markers are obtained by segmenting the point cloud data based on the markers of regular shapes with reflective properties that are fixedly arranged in the calibration site.

[0095] It should be noted that the external parameter calibration device of a vehicle-mounted multi-lidar of the present invention first obtains point cloud data from multiple laser radars on the vehicle in the calibration site through a point cloud acquisition module, and then uses a data segmentation module to segment the point cloud data corresponding to the marker. Finally, the rotation angle and position offset of each laser radar are obtained according to the point cloud data through a calculation module, thereby completing the external parameter calibration of the multiple laser radars on the vehicle.

[0096] The external parameter calibration device arranges markers with reflective properties and regular shapes in the calibration site, so that the point cloud corresponding to the marker can be accurately and quickly segmented from the point cloud data acquired by the laser radar. By utilizing the regular shape of the marker, the coordinate value of the point cloud corresponding to the center point of the marker can be easily obtained, and then the position offset of the laser radar can be obtained using the coordinates of the center point of the marker, thereby improving the calibration accuracy and efficiency of multiple laser radars using point clouds.

[0097] In a preferred embodiment of the present invention, an external parameter calibration device for a vehicle-mounted multi-laser radar provided by the present invention further includes a driving module; the driving module is used to drive the vehicle into a fixed position in a calibration site consisting of a flat ground plane, and a front plane, a left plane, and a right plane that are respectively fixedly arranged perpendicular to the ground plane.

[0098] In another preferred embodiment of the present invention, the external parameter calibration device of the vehicle-mounted multi-laser radar further includes an adjustment module, which is used to adjust the vehicle to the vehicle fixing position marked on the ground plane, and keep the vehicle body parallel to the left plane and the right plane respectively, and the vehicle direction is perpendicular to the front plane.

[0099] It should be noted that, through the setting of the driving module and the adjustment module, it is possible to ensure that the vehicle remains in a fixed position and a fixed direction within the calibration site, thereby further improving the calibration accuracy of the external parameter calibration device of the vehicle-mounted multi-laser radar.

[0100] In another preferred embodiment of the present invention, it is specifically stated that the actual coordinate value of the center point is the coordinate value of the center point of the marker in the vehicle coordinate system; wherein, the coordinate value of the center point of the marker in the vehicle coordinate system is obtained in the vehicle coordinate system after the vehicle enters the calibration site and the origin of the coordinate system of the vehicle coincides with the origin of the coordinate system preset in the calibration site.

[0101] In another preferred embodiment of the present invention, the data segmentation module 420 segments the point cloud data corresponding to each marker from the point cloud data by the following method:

[0102] Based on the regularly shaped markers with reflective properties respectively arranged at the geometric centers of the front plane, the left plane and the right plane, it is determined whether the signal strength of each point cloud in the point cloud data exceeds a preset threshold, and the point cloud with a signal strength exceeding the preset threshold is segmented from the corresponding point cloud data.

[0103] In another preferred embodiment of the present invention, the calculation module 430 calculates the rotation angle and position offset of each laser radar according to the point cloud data and the segmented point cloud data using the following method:

[0104] Selecting part of the point cloud from the point cloud data corresponding to the ground plane to obtain the normal vector of the ground plane, and obtaining the roll angle and pitch angle of each of the laser radars according to the normal vector of the ground plane and the normal vector of the ideal ground plane;

[0105] The plane normal vectors of the front plane, the left plane and the right plane are obtained from the segmented point cloud data, and the yaw angle of the forward laser radar located at the front side of the vehicle is obtained according to the plane normal vector and the ideal front plane normal vector, and the yaw angles of the side laser radars located at the left and right sides of the vehicle are obtained according to the plane normal vector and the ideal side plane normal vector;

[0106] According to the outer points corresponding to each of the markers in the segmented point cloud data, the center point coordinate value of each of the markers is obtained, and the position offset of each of the laser radars is obtained by calculating the difference between the coordinate value of each center point and the actual coordinate value of the corresponding marker center point.

[0107] The extrinsic parameter calibration device of a vehicle-mounted multi-laser radar of the present invention is used for the extrinsic parameter calibration method of the vehicle-mounted multi-laser radar in the aforementioned embodiments. Therefore, the description and definition in the extrinsic parameter calibration method of the vehicle-mounted multi-laser radar in the aforementioned embodiments can be used for understanding each execution module in the embodiments of the present invention.

[0108] Figure 5 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 5As shown, the electronic device may include: a processor 510, a communication interface 520, a memory 530 and a communication bus 540, wherein the processor 510, the communication interface 520 and the memory 530 communicate with each other through the communication bus 540. The processor 510 may call the logic instructions in the memory 530 to execute an external parameter calibration method for a vehicle-mounted multi-laser radar, the method comprising: obtaining point cloud data respectively from multiple laser radars on a vehicle in a calibration site; obtaining the rotation angle and position offset of each of the laser radars based on the obtained point cloud data; wherein the position offset is the difference between the coordinate value of the center point of the marker obtained from the point cloud data representing the marker and the actual coordinate value of the center point; the point cloud data representing the marker is based on the markers of regular shapes with reflective characteristics fixedly arranged in the calibration site, and is obtained by segmenting the point cloud data.

[0109] In addition, the logic instructions in the above-mentioned memory 530 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0110] On the other hand, the present invention also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute an external parameter calibration method for a vehicle-mounted multi-laser radar provided by the above-mentioned methods, the method including: acquiring point cloud data respectively from multiple laser radars on a vehicle in a calibration site; obtaining a rotation angle and a position offset of each of the laser radars based on the acquired point cloud data; wherein the position offset is the difference between the coordinate value of the center point of the marker obtained from the point cloud data representing the marker and the actual coordinate value of the center point; the point cloud data representing the marker is based on a regularly shaped marker with reflective properties fixedly arranged in the calibration site, and is obtained by segmenting the point cloud data.

[0111] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the above-mentioned external parameter calibration method for a vehicle-mounted multi-lidar, the method comprising: acquiring point cloud data respectively from multiple laser radars on a vehicle in a calibration site; obtaining a rotation angle and a position offset of each of the laser radars based on the acquired point cloud data; wherein the position offset is a difference between a coordinate value of a center point of the marker obtained from the point cloud data representing the marker and an actual coordinate value of the center point; the point cloud data representing the marker is obtained by segmenting the point cloud data based on a regularly shaped marker with reflective properties that is fixedly arranged in the calibration site.

[0112] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0113] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calibrating external parameters of a vehicle-mounted multi-laser radar, characterized in that: include: Point cloud data is obtained by multiple laser radars on vehicles in the calibration site; Obtaining the rotation angle and position offset of each of the laser radars based on the acquired point cloud data; The position offset is the difference between the coordinate value of the center point of the marker obtained from the point cloud data representing the marker and the actual coordinate value of the center point; The point cloud data representing the markers are obtained by segmenting the point cloud data based on the markers of regular shapes with reflective properties that are fixedly arranged in the calibration site; The point cloud data representing the marker is obtained by segmenting the point cloud data based on the markers of regular shapes with reflective properties that are fixedly arranged in the calibration site, and specifically includes: Based on the markers with regular shapes and reflective properties arranged at the geometric centers of the front plane, the left plane and the right plane in the calibration site, it is determined whether the signal strength of each point cloud in the point cloud data exceeds a preset threshold, and the point cloud with a signal strength exceeding the preset threshold is segmented from the corresponding point cloud data; The step of obtaining the rotation angle and position offset of each laser radar based on the acquired point cloud data specifically includes: Selecting part of the point cloud from the point cloud data corresponding to the ground plane to obtain the normal vector of the ground plane, and obtaining the roll angle and pitch angle of each of the laser radars according to the normal vector of the ground plane and the normal vector of the ideal ground plane; The plane normal vectors of the front plane, the left plane and the right plane are obtained from the segmented point cloud data, and the yaw angle of the forward laser radar located at the front side of the vehicle is obtained according to the plane normal vector and the ideal front plane normal vector, and the yaw angles of the side laser radars located at the left and right sides of the vehicle are obtained according to the plane normal vector and the ideal side plane normal vector; According to the outer points corresponding to each of the markers in the segmented point cloud data, the center point coordinate value of each of the markers is obtained, and the position offset of each of the laser radars is obtained by calculating the difference between the coordinate value of each center point and the actual coordinate value of the corresponding marker center point.

2. The extrinsic parameter calibration method of the vehicle-mounted multi-laser radar according to claim 1 is characterized in that: Before the point cloud data are respectively acquired by the multiple laser radars on the vehicles in the calibration site, the method further includes: The vehicle is driven into a fixed position in a calibration field consisting of a flat ground plane, and a front plane, a left plane, and a right plane which are respectively fixedly arranged perpendicularly to the ground plane.

3. The extrinsic parameter calibration method of the vehicle-mounted multi-laser radar according to claim 2 is characterized in that: Driving the vehicle into a fixed position in the calibration site specifically includes: The vehicle is adjusted to the vehicle fixing position marked on the ground plane, and the vehicle body is kept parallel to the left plane and the right plane respectively, and the vehicle direction is perpendicular to the front plane.

4. The extrinsic parameter calibration method of the vehicle-mounted multi-laser radar according to claim 3 is characterized in that: The actual coordinate value of the center point is the coordinate value of the center point of the marker in the vehicle coordinate system; The coordinate value of the center point of the marker in the vehicle coordinate system is obtained in the vehicle coordinate system by driving the vehicle into the calibration site so that the origin of the vehicle's coordinate system coincides with the origin of the coordinate system preset in the calibration site.

5. A device for implementing the external parameter calibration method of a vehicle-mounted multi-laser radar as described in any one of claims 1 to 4, characterized in that: include: A point cloud acquisition module is used to obtain point cloud data from multiple laser radars on vehicles in the calibration site; A calculation module, used to obtain the rotation angle and position offset of each of the laser radars based on the acquired point cloud data; The position offset is the difference between the coordinate value of the center point of the marker obtained from the point cloud data representing the marker and the actual coordinate value of the center point; The point cloud data representing the markers are obtained by segmenting the point cloud data based on the markers of regular shapes with reflective properties that are fixedly arranged in the calibration site.

6. The extrinsic parameter calibration device for vehicle-mounted multi-laser radar according to claim 5, characterized in that: Also includes: A driving module, used for driving the vehicle into a calibration field consisting of a flat ground plane, and a front plane, a left plane, and a right plane respectively fixedly arranged perpendicularly to the ground plane; The adjustment module is used to adjust the vehicle to the vehicle fixing position marked on the ground plane, and keep the vehicle body parallel to the left plane and the right plane respectively, and the vehicle direction is perpendicular to the front plane.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the external parameter calibration method of the vehicle-mounted multi-lidar as described in any one of claims 1 to 4 are implemented.

8. A computer program product, comprising a computer program, characterized in that When the computer program is executed by the processor, the steps of the external parameter calibration method of the vehicle-mounted multi-lidar as described in any one of claims 1 to 4 are implemented.

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