WO2022165793A1

WO2022165793A1 - Extrinsic parameter calibration method and apparatus and computer readable storage medium

Info

Publication number: WO2022165793A1
Application number: PCT/CN2021/075766
Authority: WO
Inventors: 薛连杰; 万富华; 李延召
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2021-02-07
Filing date: 2021-02-07
Publication date: 2022-08-11

Abstract

Disclosed in embodiments of the present application is an extrinsic parameter calibration method, comprising: obtaining first coordinates of a reference object in an actual coordinate system of a laser radar; determining second coordinates of the reference object in a design coordinate system of the laser radar; determining a first rotation matrix between the actual coordinate system and the design coordinate system according to the first coordinates and the second coordinates; and determining, according to the first rotation matrix and design extrinsic parameters, a target extrinsic parameter between the actual coordinate system and a coordinate system of a movable platform carrying the laser radar, the design extrinsic parameters being extrinsic parameters between the design coordinate system and the coordinate system of the movable platform. According to the method disclosed in the embodiments of the present application, the extrinsic parameter between the actual coordinate system of the laser radar and the coordinate system of the movable platform can be calibrated with high precision.

Description

外参标定方法、装置及计算机可读存储介质External parameter calibration method, device and computer readable storage medium

技术领域technical field

本申请涉及外参标定技术领域，尤其涉及一种外参标定方法、装置及计算机可读存储介质。The present application relates to the technical field of external parameter calibration, and in particular, to an external parameter calibration method, device, and computer-readable storage medium.

背景技术Background technique

可移动平台可以通过搭载的激光雷达对环境进行感知。在对可移动平台上的激光雷达进行安装时，激光雷达需要按照设计的角度和位置进行安装。但激光雷达的安装存在误差，这种误差使得激光雷达采集到的点云点的坐标若通过设计外参进行转换，转换后的坐标所指示的点云点相对于可移动平台所在的位置将是错误的，不利于可移动平台利用点云进行诸如避障。The mobile platform can perceive the environment through the onboard lidar. When installing the lidar on the movable platform, the lidar needs to be installed according to the designed angle and position. However, there is an error in the installation of the lidar. This error causes the coordinates of the point cloud points collected by the lidar to be converted by designing external parameters, and the position of the point cloud point indicated by the converted coordinates relative to the movable platform will be Wrong, it is not conducive to the use of point clouds for mobile platforms such as obstacle avoidance.

发明内容SUMMARY OF THE INVENTION

有鉴于此，本申请实施例提供了一种外参标定方法、装置及计算机可读存储介质，目的之一是标定出更高精度的激光雷达的实际坐标系和可移动平台的坐标系之间的外参。In view of this, the embodiments of the present application provide an external parameter calibration method, device, and computer-readable storage medium, one of which is to calibrate the actual coordinate system of the laser radar with higher precision and the coordinate system of the movable platform. of external parameters.

本申请实施例第一方面提供了一种外参标定方法，包括：A first aspect of the embodiments of the present application provides an external parameter calibration method, including:

获取参照物在激光雷达的实际坐标系下的第一坐标；Obtain the first coordinate of the reference object in the actual coordinate system of the lidar;

确定所述参照物在所述激光雷达的设计坐标系下的第二坐标；determining the second coordinate of the reference object in the design coordinate system of the lidar;

根据所述第一坐标和所述第二坐标，确定所述实际坐标系和所述设计坐标系之间的第一旋转矩阵；determining a first rotation matrix between the actual coordinate system and the design coordinate system according to the first coordinate and the second coordinate;

根据所述第一旋转矩阵和设计外参，确定所述实际坐标系和搭载所述激光雷达的可移动平台的坐标系之间的目标外参，所述设计外参是所述设计坐标系和所述可移动平台的坐标系之间的外参。According to the first rotation matrix and design extrinsic parameters, determine the target extrinsic parameters between the actual coordinate system and the coordinate system of the movable platform carrying the lidar, and the design extrinsic parameters are the design coordinate system and The extrinsic parameter between the coordinate systems of the movable platform.

本申请实施例第二方面提供了一种外参标定装置，包括：处理器和存储有计算机程序的存储器，所述处理器在执行所述计算机程序时实现以下步骤：A second aspect of an embodiment of the present application provides an external parameter calibration device, comprising: a processor and a memory storing a computer program, where the processor implements the following steps when executing the computer program:

本申请实施例第三方面提供了一种计算机可读存储介质，所述计算机可读存储介质存储有计算机程序，所述计算机程序被处理器执行时实现上述第一方面提供的外参标定方法。A third aspect of the embodiments of the present application provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, implements the external parameter calibration method provided in the first aspect.

本申请实施例提供的外参标定方法，并不是直接求解激光雷达的实际坐标系和可移动平台的坐标系之间的转换关系，而是先考虑激光雷达的实际坐标系到设计坐标系之间的转换，再结合所述设计坐标系到可移动平台的坐标系之间的转换，最终得到目标外参。由于用于所述设计坐标系和可移动平台的坐标系之间转换的设计外参是已知且准确的，并且在所述实际坐标系和所述设计坐标系之间可以忽略平移向量，只确定旋转矩阵(第一旋转矩阵)，因此在整个目标外参的确定过程中，需要新确定的外参只有第一旋转矩阵，这一方面简化了计算流程，提高了计算效率，另一方面由于需要重新计算的外参少，因此在目标外参中引入的误差较小，提高了标定出的目标外参的准确度。The external parameter calibration method provided in the embodiment of the present application does not directly solve the conversion relationship between the actual coordinate system of the lidar and the coordinate system of the movable platform, but first considers the relationship between the actual coordinate system of the lidar and the design coordinate system The conversion between the design coordinate system and the coordinate system of the movable platform is combined with the conversion between the coordinate system of the movable platform, and the target external parameter is finally obtained. Since the design extrinsic parameters for conversion between the design coordinate system and the coordinate system of the movable platform are known and accurate, and the translation vector can be ignored between the actual coordinate system and the design coordinate system, only Determine the rotation matrix (the first rotation matrix), so in the whole process of determining the external parameters of the target, only the first rotation matrix needs to be newly determined for the external parameters, which simplifies the calculation process and improves the calculation efficiency. There are few external parameters that need to be recalculated, so the error introduced in the target external parameters is small, and the accuracy of the calibrated target external parameters is improved.

附图说明Description of drawings

为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative labor.

图1是本申请实施例提供的激光雷达在无人车上的安装角度和位置示意图。FIG. 1 is a schematic diagram of the installation angle and position of the lidar on the unmanned vehicle provided by the embodiment of the present application.

图2是本申请实施例提供的外参标定方法的流程图。FIG. 2 is a flowchart of an external parameter calibration method provided by an embodiment of the present application.

图3是本申请实施例提供的一种靶标的结构示意图。FIG. 3 is a schematic structural diagram of a target provided in an embodiment of the present application.

图4是本申请实施例提供的参照物布局的侧视图。FIG. 4 is a side view of a reference object layout provided by an embodiment of the present application.

图5是本申请实施例提供的参照物布局的正视图。FIG. 5 is a front view of a reference object layout provided by an embodiment of the present application.

图6是本申请实施例提供的通过激光雷达对参照物进行测量的场景示意图。FIG. 6 is a schematic diagram of a scene in which a reference object is measured by a laser radar according to an embodiment of the present application.

图7是本申请实施例提供的参照物在激光雷达的实际坐标系下的第一方向向量的示意图。FIG. 7 is a schematic diagram of a first direction vector of a reference object in an actual coordinate system of a lidar according to an embodiment of the present application.

图8是本申请实施例提供的参照物在激光雷达的设计坐标系下的第二方向向量的示意图。FIG. 8 is a schematic diagram of a second direction vector of a reference object provided in an embodiment of the present application in a design coordinate system of a lidar.

图9是本申请实施例提供的第一方向向量和第二方向向量的对比图。FIG. 9 is a comparison diagram of a first direction vector and a second direction vector provided by an embodiment of the present application.

图10是本申请实施例提供的外参标定装置的结构示意图。FIG. 10 is a schematic structural diagram of an external parameter calibration device provided by an embodiment of the present application.

具体实施方式Detailed ways

下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

可移动平台，例如无人车、无人机、无人船、机器人等，需要对环境进行感知。在一种实施方式中，可移动平台可以搭载激光雷达，通过激光雷达对环境进行扫描，可以得到环境对应的点云数据，通过对点云数据进行分析处理，可移动平台可以获知环境所包含的物体的信息，比如物体的位置、物体的类别等等。Movable platforms, such as unmanned vehicles, drones, unmanned ships, robots, etc., need to perceive the environment. In one embodiment, the movable platform can be equipped with a laser radar, and the environment can be scanned by the laser radar to obtain point cloud data corresponding to the environment. Information about the object, such as the location of the object, the category of the object, and so on.

在可移动平台上安装激光雷达时，激光雷达需要按照设计的角度和位置进行安装。这里可以以无人车(自动驾驶汽车)为例，如图1所示，在设计中，激光雷达可以安装在无人车的左前方，激光雷达的安装角度可以是激光雷达的正射方向与无人车的前进方向一致，即当激光雷达以设计的角度安装在无人车上时，激光雷达的坐标系(XYZ)与无人车的车身坐标系(X’Y’Z’)的各轴方向一致，这里，可以将激光雷达在设计的角度和设计的位置时的坐标系称为激光雷达的设计坐标系。When installing lidar on a movable platform, the lidar needs to be installed according to the designed angle and position. Here, an unmanned vehicle (autonomous vehicle) can be taken as an example. As shown in Figure 1, in the design, the lidar can be installed in the left front of the unmanned vehicle, and the installation angle of the lidar can be the ortho-radiation direction of the lidar. The forward direction of the unmanned vehicle is the same, that is, when the lidar is installed on the unmanned vehicle at the designed angle, the coordinate system (XYZ) of the lidar and the body coordinate system (X'Y'Z') of the unmanned vehicle are different. The axis directions are the same. Here, the coordinate system of the lidar at the designed angle and the designed position can be called the design coordinate system of the lidar.

若激光雷达可以无误差的以设计的角度安装在可移动平台的设计位置上，则激光雷达采集到的点云点的坐标是在激光雷达的设计坐标系下的坐标，该设计坐标系下的坐标通过设计外参转换到可移动平台的坐标系下后，可以准确的描述点云点相对于可移动平台所在的位置。但激光雷达的安装是有误差的，这种误差使得激光雷达采集到的点云点的坐标所在的坐标系并不是所述设计坐标系，若该坐标仍然通过所述设计外参进行转换，转换后的坐标所指示的点云点相对于可移动平台所在的位置将是错误的，进一步的，若可移动平台依据这些点云点的坐标进行障碍物识别，则识别出的障碍物位置也将是错误的，从而造成避障事故。这里，激光雷达在实际的安装位置和安装角度下对应的坐标系可以称为激光雷达的实际坐标系。If the lidar can be installed at the design position of the movable platform at the designed angle without error, the coordinates of the point cloud points collected by the lidar are the coordinates under the design coordinate system of the lidar, and the coordinates in the design coordinate system After the coordinates are converted into the coordinate system of the movable platform through the design external parameters, the position of the point cloud point relative to the movable platform can be accurately described. However, there is an error in the installation of the lidar. This error makes the coordinate system where the coordinates of the point cloud points collected by the lidar are located is not the design coordinate system. If the coordinates are still converted through the design external parameters, the conversion The position of the point cloud point indicated by the latter coordinates relative to the movable platform will be wrong. Further, if the movable platform performs obstacle recognition based on the coordinates of these point cloud points, the identified obstacle position will also be incorrect. is wrong, resulting in an obstacle avoidance accident. Here, the coordinate system corresponding to the laser radar at the actual installation position and installation angle can be called the actual coordinate system of the laser radar.

为解决上述问题，在一种实施方式中，可以对激光雷达的实际坐标系和可移动平台的坐标系之间的外参(目标外参)进行标定，标定出的目标外参可以用于将激光雷达采集到的点云点的坐标从激光雷达的实际坐标系转换到可移动平台的坐标系下，并且该转换到可移动平台的坐标系下的坐标与点云点相对于可移动平台所在的真实位置相匹配。这里，若可移动平台是无人车，则可移动平台的坐标系可以称为车身坐标系，若可移动平台是无人机，则可移动平台的坐标系可以称为机体坐标系。In order to solve the above problems, in one embodiment, the external parameters (target external parameters) between the actual coordinate system of the lidar and the coordinate system of the movable platform can be calibrated, and the calibrated target external parameters can be used to The coordinates of the point cloud points collected by the lidar are converted from the actual coordinate system of the lidar to the coordinate system of the movable platform, and the coordinates converted to the coordinate system of the movable platform and the point cloud points are relative to where the movable platform is located. match the real location. Here, if the movable platform is an unmanned vehicle, the coordinate system of the movable platform can be called the body coordinate system, and if the movable platform is a drone, the coordinate system of the movable platform can be called the body coordinate system.

在对所述目标外参进行标定时，在一种实施方式中，可以在标定场地中布置参照物，参照物可以是各种可被激光雷达探测到的物体，其可以作为标定过程中待测量的目标物，比如可以是靶标。在参照物布置完成后，可以通过高精度的测量装置测量出参照物在可移动平台的坐标系下准确的第三坐标，并可以通过可移动平台搭载的激光雷达对场景进行点云采集，获取参照物在激光雷达的实际坐标系下的第一坐标，从而根据所述第一坐标和所述第三坐标可以确定所述实际坐标系和所述可移动平台的坐标系之间的目标外参。When calibrating the target external parameter, in one embodiment, a reference object can be arranged in the calibration site, and the reference object can be various objects that can be detected by lidar, which can be used as the object to be measured during the calibration process. target, such as a target. After the reference object is arranged, the accurate third coordinate of the reference object in the coordinate system of the movable platform can be measured by a high-precision measuring device, and the point cloud of the scene can be collected by the lidar mounted on the movable platform to obtain The first coordinate of the reference object in the actual coordinate system of the lidar, so that the target external parameter between the actual coordinate system and the coordinate system of the movable platform can be determined according to the first coordinate and the third coordinate .

外参可以用于坐标在不同坐标系下进行转换，比如所述目标外参可以用于坐标在所述实际坐标系和所述可移动平台的坐标系下进行转换。外参可以包括旋转矩阵和平移向量，在上述实施方式中，在根据所述第一坐标和所述第三坐标确定所述目标外参时，需要对目标外参中的旋转矩阵和平移向量都进行优化，即需要通过优化算法求解出目标外参中的旋转矩阵和平移向量。但在优化求解的过程中，旋转矩阵和平移向量并不一定能很好的收敛，且最终求解出的目标外参也不一定有足够的精度，即利用该目标外参对激光雷达采集的点云点的坐标进行转换后，转换后的坐标所指示的点云点相对于可移动平台所在的位置仍然不准确。The external parameters can be used to convert coordinates in different coordinate systems, for example, the target external parameters can be used to convert coordinates in the actual coordinate system and the coordinate system of the movable platform. The external parameter may include a rotation matrix and a translation vector. In the above embodiment, when determining the target external parameter according to the first coordinate and the third coordinate, both the rotation matrix and the translation vector in the target external parameter need to be determined. To optimize, it is necessary to solve the rotation matrix and translation vector in the target external parameter through the optimization algorithm. However, in the process of optimization and solution, the rotation matrix and translation vector may not be well converged, and the final solution of the target external parameter may not have sufficient accuracy, that is, the point collected by the lidar using the target external parameter. After the coordinates of the cloud point are converted, the position of the point cloud point indicated by the converted coordinates relative to the movable platform is still inaccurate.

考虑到上述问题，本申请实施例提供了一种外参标定方法，可以参考图2，图2是本申请实施例提供的外参标定方法的流程图，该方法可以包括以下步骤：Considering the above problems, an embodiment of the present application provides a method for calibrating external parameters. Referring to FIG. 2, FIG. 2 is a flowchart of the method for calibrating external parameters provided by the embodiment of the present application. The method may include the following steps:

S202、获取参照物在激光雷达的实际坐标系下的第一坐标。S202: Acquire the first coordinates of the reference object in the actual coordinate system of the lidar.

S204、确定所述参照物在所述激光雷达的设计坐标系下的第二坐标。S204. Determine the second coordinate of the reference object in the design coordinate system of the lidar.

S206、根据所述第一坐标和所述第二坐标，确定所述实际坐标系和所述设计坐标系之间的第一旋转矩阵。S206. Determine a first rotation matrix between the actual coordinate system and the design coordinate system according to the first coordinate and the second coordinate.

S208、根据所述第一旋转矩阵和设计外参，确定所述实际坐标系和搭载所述激光雷达的可移动平台的坐标系之间的目标外参。S208 , according to the first rotation matrix and the design external parameters, determine the target external parameters between the actual coordinate system and the coordinate system of the movable platform carrying the lidar.

如前所述，在对目标外参进行标定时，可以在标定场地中布置参照物。为使激光雷达测量得到的参照物的第一坐标更准确，在一种实施方式中，参照物可以包括第一部分和第二部分，其中第一部分的反射率高于第二部分的反射率。由于第二部分的反射率低于第一部分的反射率，因此第一部分对应的点云可以在第二部分对应的点云的衬托下有更清晰的轮廓，从而可以使激光雷达测量得到的参照物的第一坐标更准确。进一步的，第一部分可以被第二部分包围，如此，第一部分对应的点云的整个轮廓都可以在第二部分对应的点云的衬托下更清晰。在一个例子中，第一部分可以位于参照物的中部，中部以外的其他部位可以是第二部分。As mentioned above, when calibrating the target external parameter, a reference object can be arranged in the calibration field. In order to make the first coordinate of the reference object measured by the lidar more accurate, in an embodiment, the reference object may include a first part and a second part, wherein the reflectivity of the first part is higher than that of the second part. Since the reflectivity of the second part is lower than that of the first part, the point cloud corresponding to the first part can have a clearer outline under the background of the point cloud corresponding to the second part, so that the reference object measured by the lidar can be obtained. The first coordinate of is more accurate. Further, the first part can be surrounded by the second part, so that the entire outline of the point cloud corresponding to the first part can be more clearly set off against the point cloud corresponding to the second part. In one example, the first part may be located in the middle of the reference object, and other parts other than the middle part may be the second part.

可以参考图3，图3是本申请实施例提供的一种靶标的结构示意图。如图3所示，参照物可以是靶标，靶标可以包括第一部分310和第二部分320，第一部分可以位于靶标的中心部位，第二部分可以将第一部分包围，位于靶标的边界部位。在一个例子中，靶标的第二部分可以用黑色泡棉制作，第一部分可以用全反射材料制作。在一个例子中，靶标的第二部分可以是黑色泡棉，黑色泡棉可以作为靶标的底板，第一部分可以是全反射贴片，全反射贴片可以贴设在黑色泡棉的中心位置。在图3所示的例子中，靶标是50CM*50CM的正方形板，但可以理解的，靶标的尺寸和形状不局限于图3所示的设计，其可以根据激光雷达的扫描密度和标定场地的面积等灵活设计成长方形板、圆形板等各种其他尺寸和形状。Referring to FIG. 3 , FIG. 3 is a schematic structural diagram of a target provided in an embodiment of the present application. As shown in FIG. 3 , the reference can be a target, and the target can include a first part 310 and a second part 320 , the first part can be located at the center of the target, and the second part can surround the first part and located at the border of the target. In one example, the second part of the target can be made of black foam and the first part can be made of a totally reflective material. In one example, the second part of the target can be black foam, the black foam can be used as the bottom plate of the target, the first part can be a total reflection patch, and the total reflection patch can be attached to the center of the black foam. In the example shown in Figure 3, the target is a 50CM*50CM square plate, but it can be understood that the size and shape of the target are not limited to the design shown in Figure 3, which can be determined according to the scanning density of the lidar and the calibration site. Area and other flexible designs for rectangular plates, circular plates and various other sizes and shapes.

在布置所述参照物时，在一种实施方式中，所布置的参照物的数量可以有N个，其中N是大于或等于3的整数。考虑到激光雷达在不同距离和视场内的不同位置有不同的精度特性，因此参照物的排布可以尽量覆盖更多的距离和更多的视场位置。比如，在一种实施方式中，N个参照物可以排列成多个参照物排，每一排可以包含一个或多个参照物，每一排可以对应激光雷达视场前的一个距离。可以参考图4，图4中的N个参照物(靶标)可以排列成2个参照物排，其中，第一参照物排可以位于激光雷达视场前7m的距离，第二参照物排可以位于激光雷达视场前10m的距离。When arranging the reference objects, in one embodiment, the number of the reference objects to be arranged may be N, where N is an integer greater than or equal to 3. Considering that lidar has different accuracy characteristics at different distances and different positions in the field of view, the arrangement of the reference objects can cover as many distances and more positions as possible in the field of view. For example, in one embodiment, the N reference objects may be arranged into multiple reference object rows, each row may contain one or more reference objects, and each row may correspond to a distance in front of the lidar field of view. Referring to Figure 4, the N reference objects (targets) in Figure 4 can be arranged into 2 reference object rows, wherein the first reference object row can be located at a distance of 7m in front of the lidar field of view, and the second reference object row can be located at a distance of 7m. The distance of 10m in front of the lidar field of view.

考虑到不同参照物排之间的参照物可能形成遮挡，比如图4中，第一参照物排的参照物可能对第二参照物排的参照物形成遮挡，导致激光雷达无法探测到第二参照物排中被遮挡的参照物，因此，在一种实施方式中，参照物排之间的参照物可以交叉排布。如图5所示，各个参照物所处的位置互相错开，从而每个参照物都可以被激光雷达扫描到，不会存在后排参照物被前排参照物遮挡的情况。Considering that the reference objects between different reference object rows may form occlusions, for example, in Figure 4, the reference objects of the first reference object row may form occlusions to the reference objects of the second reference object row, resulting in the lidar being unable to detect the second reference object. Therefore, in an embodiment, the reference objects between the reference object rows can be arranged in a cross manner. As shown in Figure 5, the positions of the reference objects are staggered from each other, so that each reference object can be scanned by the lidar, and there is no situation that the reference objects in the rear row are blocked by the reference objects in the front row.

在一种实施方式中，N个参照物可以分布在激光雷达视场中的不同位置。如图5所示，在激光雷达的视场内，有部分参照物分布在视场的上方，部分参照物分布在视场的左侧，部分参照物分布在视场的右侧，从而能够较全面的覆盖激光雷达视场中的各个区域，使最终标定的目标外参有更高的精度。In one embodiment, the N reference objects may be distributed at different positions in the lidar field of view. As shown in Figure 5, in the field of view of the lidar, some reference objects are distributed above the field of view, some reference objects are distributed on the left side of the field of view, and some reference objects are distributed on the right side of the field of view, so that the Comprehensive coverage of each area in the lidar field of view, so that the final calibrated target external parameters have higher accuracy.

在标定场地的参照物布置完成后，可以将可移动平台停放在指定位置，并通过可移动平台搭载的激光雷达采集场景对应的点云，根据所采集的点云，可以确定参照物在激光雷达的实际坐标系下的第一坐标。可以参考图6，如图6所示，可移动平台是无人车，无人车在停放在指定位置后，可以通过其左前方的激光雷达对视场前的参照物(靶标)进行测量，从而可以确定出参照物的所述第一坐标。需要说明的是，图6所示的参照物的布局仅作为示例，实际的参照物布局可以根据实际需求自行设计。After the reference object arrangement of the calibration site is completed, the movable platform can be parked at the designated position, and the point cloud corresponding to the scene can be collected by the lidar carried on the movable platform. The first coordinate in the actual coordinate system of . You can refer to Figure 6. As shown in Figure 6, the movable platform is an unmanned vehicle. After the unmanned vehicle is parked in a designated position, the reference object (target) in front of the field of view can be measured by the lidar in front of it. Thus, the first coordinates of the reference object can be determined. It should be noted that the layout of the reference objects shown in FIG. 6 is only an example, and the actual layout of the reference objects can be designed according to actual needs.

在根据所采集的点云确定参照物的第一坐标时，在一种实施方式中，可以将参照物中高反射率的第一部分的中心点坐标确定为参照物的第一坐标，如图3所示，即可以将靶标的靶心坐标确定为靶标的坐标。具体的，在通过激光雷达采集到场景对应的点云后，可以根据点云中点云点的反射率，提取出反射率高于阈值的目标点云点。可以理解的，目标点云点即对应参照物中第一部分对应的点云点。由于参照物的数量有多个，因此可以对提取出的目标点云点根据点云点之间的距离进行聚类，得到多个类别，这里，每个类别可以对应一个参照物的所述第一部分。对所述多个类别中的每个类别，可以计算该类别中点云的中心点坐标，将该中心点坐标确定为该类别所对应的参照物的第一坐标。When the first coordinates of the reference object are determined according to the collected point cloud, in one embodiment, the coordinates of the center point of the first part of the reference object with high reflectivity may be determined as the first coordinates of the reference object, as shown in FIG. 3 . shown, that is, the coordinates of the bullseye of the target can be determined as the coordinates of the target. Specifically, after the point cloud corresponding to the scene is collected by the lidar, the target point cloud point whose reflectivity is higher than the threshold can be extracted according to the reflectivity of the point cloud point in the point cloud. It can be understood that the target point cloud point corresponds to the point cloud point corresponding to the first part of the reference object. Since there are multiple reference objects, the extracted target point cloud points can be clustered according to the distance between the point cloud points to obtain multiple categories. Here, each category can correspond to the first reference object. part. For each of the multiple categories, the coordinates of the center point of the point cloud in the category may be calculated, and the coordinates of the center point may be determined as the first coordinates of the reference object corresponding to the category.

在计算一个类别中点云的中心点坐标时，可以有多种实施方式。在一种实施方式中，可以计算该类别中的各个点云点的坐标的平均值，将该平均值对应的坐标确定为该类别的中心点坐标。在一种实施方式中，可以确定该类别的点云轮廓，从而根据位于该轮廓的点云点的坐标计算出该类别对应的中心点坐标。When calculating the coordinates of the center point of a point cloud in a class, there can be various implementations. In one embodiment, the average value of the coordinates of each point cloud point in the category may be calculated, and the coordinates corresponding to the average value may be determined as the coordinates of the center point of the category. In one embodiment, the point cloud contour of the category can be determined, so that the coordinates of the center point corresponding to the category are calculated according to the coordinates of the point cloud points located in the contour.

需要说明的是，上述实施方式中，需要根据激光雷达采集的参照物对应的点云点来确定参照物的第一坐标，因此，为使确定出的参照物的第一坐标更准确，激光雷达所采集的点云点应该更均匀的覆盖整个参照物。在一种实施方式中，激光雷达可以是非重复扫描激光雷达，其所扫描的区域的点云点可以更密集，也可以有更均匀的分布，因此计算出的参照物的第一坐标更准确。在一种实施方式中，激光雷达可以是重复扫描激光雷达，如此，其需要配置足够多的激光线数以降低扫描得到的点云点行与点云点行之间的间隔，否则，计算出的参照物的第一坐标可能不够准确。It should be noted that, in the above embodiment, the first coordinate of the reference object needs to be determined according to the point cloud point corresponding to the reference object collected by the lidar. Therefore, in order to make the determined first coordinate of the reference object more accurate, the lidar The collected point cloud points should cover the entire reference object more evenly. In one embodiment, the lidar may be a non-repetitive scanning lidar, and the point cloud points in the area scanned by the lidar may be denser or more uniformly distributed, so the calculated first coordinate of the reference object is more accurate. In one embodiment, the lidar can be a repetitive scanning lidar, so it needs to configure enough laser lines to reduce the interval between the point cloud point row and the point cloud point row obtained by scanning, otherwise, calculate The first coordinates of the reference object may not be accurate enough.

对于参照物在激光雷达的设计坐标系下的第二坐标，在一种实施方式中，可以根据设计外参对参照物在可移动平台的坐标系下的第三坐标进行转换得到。在前文已有提及，参照物在可移动平台的坐标系下的坐标可以通过高精度的测量装置测量得到，这里，测量装置可以是全站仪、三维激光扫描仪等。可以举个例子，比如可移动平台是无人车，可以将测量装置固定在无人车停放在指定位置时的车身坐标系的原点处，从而可以通过测量装置对参照物的位置进行测量，则测量得到的参照物的坐标即为参照物在无人车的车身坐标系下的第三坐标。该第三坐标可以通过设计外参从可移动平台的坐标系转换到激光雷达的设计坐标系下，设计外参是在设计阶段就已经确定的激光雷达的设计坐标系和可移动平台的坐标系之间的外参，第三坐标在通过所述设计外参进行转换后，转换后的坐标即为参照物在激光雷达的设计坐标系下的第二坐标。For the second coordinate of the reference object under the design coordinate system of the lidar, in one embodiment, the third coordinate of the reference object under the coordinate system of the movable platform can be obtained by converting the reference object according to the design external parameters. As mentioned above, the coordinates of the reference object in the coordinate system of the movable platform can be measured by a high-precision measuring device. Here, the measuring device can be a total station, a three-dimensional laser scanner, or the like. For example, if the movable platform is an unmanned vehicle, the measuring device can be fixed at the origin of the body coordinate system when the unmanned vehicle is parked at the specified position, so that the position of the reference object can be measured by the measuring device, then The measured coordinates of the reference object are the third coordinates of the reference object in the body coordinate system of the unmanned vehicle. The third coordinate can be converted from the coordinate system of the movable platform to the design coordinate system of the lidar through the design external parameters. The design external parameters are the design coordinate system of the lidar and the coordinate system of the movable platform that have been determined in the design stage. After the external parameter between and the third coordinate is converted by the design external parameter, the converted coordinate is the second coordinate of the reference object in the design coordinate system of the lidar.

考虑到激光雷达在安装时的平移误差较小，并且平移误差对坐标转换后的准确度影响也较小，因此，可以忽略激光雷达安装时的平移误差，只考虑激光雷达在安装时的角度误差，角度误差即激光雷达的安装角度和设计角度之间的偏差。在只考虑激光雷达的安装角度和设计角度之间的偏差时，即可以只考虑激光雷达的实际坐标系和设计坐标系之间的旋转变换关系，而可以忽略两者的平移变换关系，因此，在确定所述实际坐标系和所述设计坐标系之间的外参时，可以只确定外参中的旋转矩阵(即第一旋转矩阵)，忽略外参中的平移向量。Considering that the translation error of the lidar during installation is small, and the translation error has little effect on the accuracy after coordinate conversion, therefore, the translation error of the lidar can be ignored during installation, and only the angle error of the lidar during installation is considered. , the angle error is the deviation between the installation angle and the design angle of the lidar. When only the deviation between the installation angle and the design angle of the lidar is considered, only the rotation transformation relationship between the actual coordinate system and the design coordinate system of the lidar can be considered, and the translation transformation relationship between the two can be ignored. Therefore, When determining the external parameter between the actual coordinate system and the design coordinate system, only the rotation matrix (ie, the first rotation matrix) in the external parameter may be determined, and the translation vector in the external parameter is ignored.

第一旋转矩阵可以根据参照物在激光雷达的实际坐标系下的第一坐标和参照物在激光雷达的设计坐标系下的第二坐标确定。具体的，在一种实施方式中，可以将参照物在所述实际坐标系下的第一坐标转化为参照物在所述实际坐标系下的方向向量(第一方向向量)，相应的，参照物在所述设计坐标系下的第二坐标也可以转化为参照物在所述设计坐标系下的方向向量(第二方向向量)，从而，可以通过配准(或者说对齐)所述第一方向向量和第二方向向量，得到所述第一旋转矩阵。所谓配准所述第一方向向量和所述第二方向向量，即求解一个旋转矩阵使该旋转矩阵作用在所述第一方向向量后，第一方向向量可以旋转至尽可能与第二方向向量重合。可以参考图7至图9，图7示出参照物在激光雷达的实际坐标系下的第一方向向量，图8示出参照物在激光雷达的设计坐标系下的第二方向向量，图9示出第一方向向量和第二方向向量的对比图。The first rotation matrix may be determined according to the first coordinates of the reference object in the actual coordinate system of the lidar and the second coordinates of the reference object in the design coordinate system of the lidar. Specifically, in one embodiment, the first coordinate of the reference object in the actual coordinate system can be converted into a direction vector (first direction vector) of the reference object in the actual coordinate system. Correspondingly, refer to The second coordinate of the object under the design coordinate system can also be converted into the direction vector (second direction vector) of the reference object under the design coordinate system, so that the first the direction vector and the second direction vector to obtain the first rotation matrix. The so-called registration of the first direction vector and the second direction vector is to solve a rotation matrix so that after the rotation matrix acts on the first direction vector, the first direction vector can be rotated to be as close to the second direction vector as possible. coincide. 7 to 9, Fig. 7 shows the first direction vector of the reference object in the actual coordinate system of the lidar, Fig. 8 shows the second direction vector of the reference object in the design coordinate system of the lidar, Fig. 9 A comparison diagram showing the first direction vector and the second direction vector.

对所述第一方向向量和所述第二方向向量进行配准时，具体的，可以对第一方向向量进行归一化处理，归一化后的第一方向向量可以记为β，可以对第二方向向量进行归一化处理，归一化后的第二方向向量可以记为α。可以将多个所述第一方向向量记为矩阵B，将多个所述第二方向向量记为矩阵A，矩阵B和矩阵A如下：When registering the first direction vector and the second direction vector, specifically, the first direction vector may be normalized, the normalized first direction vector may be recorded as β, and the first direction vector may be recorded as β. The two direction vectors are normalized, and the normalized second direction vector can be recorded as α. A plurality of the first direction vectors may be denoted as matrix B, and a plurality of the second direction vectors may be denoted as matrix A, and matrix B and matrix A are as follows:

如前所述，要确定的第一旋转矩阵是为了使第一旋转矩阵作用在第一方向向量后，第一方向向量可以与第二方向向量尽可能重合，则从数学形式上可以表示为经过旋转之后的第一方向向量和第二方向向量的内积最大的问题。该问题可表示为如下形式：As mentioned above, the first rotation matrix to be determined is so that after the first rotation matrix acts on the first direction vector, the first direction vector and the second direction vector can overlap as much as possible, which can be expressed in mathematical form as passing through The problem that the inner product of the first direction vector and the second direction vector after rotation is the largest. The problem can be expressed as follows:

其中，R表示所述第一旋转矩阵，可以将矩阵BA ^T进行奇异值分解，即SVD分解，从而可以得到UDVT，U为左奇异值向量，D为对角矩阵，V为右奇异值向量。将UDVT代入上式可得： Wherein, R represents the first rotation matrix, and the matrix BAT can be decomposed by singular value, that is, SVD decomposition, so as to obtain ^UDVT , U is the left singular value vector, D is the diagonal matrix, and V is the right singular value vector. Substitute UDVT into the above formula to get:

由于D为对角矩阵，因此R的解为：Since D is a diagonal matrix, the solution for R is:

R＝VU ^T R= ^VUT

此旋转矩阵R即为激光雷达的实际坐标系和设计坐标系之间的外参旋转矩阵，即所述的第一旋转矩阵。The rotation matrix R is the external parameter rotation matrix between the actual coordinate system and the design coordinate system of the lidar, that is, the first rotation matrix.

利用所述第一旋转矩阵，可以将激光雷达测量得到的在实际坐标系下的坐标转换到设计坐标系下，而在设计坐标系下的坐标可以通过已知的设计外参转换到可移动平台的坐标系下，实现了坐标从激光雷达的实际坐标系到可移动平台的坐标系的转换。换言之，实际坐标系和可移动平台的坐标系之间的目标外参包括所述第一旋转矩阵和所述设计外参，第一旋转矩阵用于坐标在所述实际坐标系和所述设计坐标系之间转换，设计外参用于坐标在所述设计坐标系和可移动平台的坐标系之间转换。Using the first rotation matrix, the coordinates in the actual coordinate system measured by the lidar can be converted into the design coordinate system, and the coordinates in the design coordinate system can be converted into the movable platform through the known design external parameters Under the coordinate system, the transformation of coordinates from the actual coordinate system of the lidar to the coordinate system of the movable platform is realized. In other words, the target extrinsic parameter between the actual coordinate system and the coordinate system of the movable platform includes the first rotation matrix and the design extrinsic parameter, and the first rotation matrix is used for coordinates between the actual coordinate system and the design coordinate For conversion between systems, the design external parameters are used for coordinate conversion between the design coordinate system and the coordinate system of the movable platform.

在一种实施方式中，目标外参可以包括目标旋转矩阵和目标平移向量，所述设计外参包括设计旋转矩阵和设计平移向量，则目标外参中的目标旋转矩阵可以是所述第一旋转矩阵和所述设计旋转矩阵融合得到的，比如在一个例子中，目标旋转矩阵Rtarget、第一旋转矩阵R和设计旋转矩阵Rd可以具有以下关系：Rtarget＝R*Rd。由于忽略了所述实际坐标系和所述设计坐标系之间的平移变换，因此目标外参中的目标平移向量可以复用设计外参的设计平移向量，即目标平移向量ttarget可以与设计平移向量td相同，即ttarget＝td。In one embodiment, the target external parameter may include a target rotation matrix and a target translation vector, the design external parameter may include a design rotation matrix and a design translation vector, and the target rotation matrix in the target external parameter may be the first rotation The matrix and the design rotation matrix are obtained by fusion. For example, in an example, the target rotation matrix Rtarget, the first rotation matrix R and the design rotation matrix Rd may have the following relationship: Rtarget=R*Rd. Since the translation transformation between the actual coordinate system and the design coordinate system is ignored, the target translation vector in the target extrinsic parameter can reuse the design translation vector of the design extrinsic parameter, that is, the target translation vector ttarget can be the same as the design translation vector td is the same, ie ttarget=td.

可以参考图10，图10是本申请实施例提供的外参标定装置的结构示意图，该装置可以包括：处理器1010和存储有计算机程序的存储器1020，所述处理器在执行所述计算机程序时实现以下步骤：Referring to FIG. 10, FIG. 10 is a schematic structural diagram of an external parameter calibration apparatus provided in an embodiment of the present application. The apparatus may include: a processor 1010 and a memory 1020 storing a computer program. When the processor executes the computer program Implement the following steps:

可选的，所述参照物在所述设计坐标系下的第二坐标是所述参照物在所述可移动平台的坐标系下的第三坐标通过所述设计外参转换得到的。Optionally, the second coordinate of the reference object under the design coordinate system is obtained by converting the third coordinate of the reference object under the coordinate system of the movable platform through the design external parameter.

可选的，所述参照物在所述可移动平台的坐标系下的第三坐标是利用测量设备测量得到的。Optionally, the third coordinate of the reference object in the coordinate system of the movable platform is obtained by measuring using a measuring device.

可选的，所述测量设备包括：全站仪或三维激光扫描仪。Optionally, the measurement equipment includes: a total station or a three-dimensional laser scanner.

可选的，所述参照物包括第一部分和第二部分，所述第一部分的反射率高于所述第二部分的反射率。Optionally, the reference object includes a first part and a second part, and the reflectivity of the first part is higher than that of the second part.

可选的，所述第一部分被所述第二部分包围。Optionally, the first portion is surrounded by the second portion.

可选的，所述第一部分位于所述参照物的中部。Optionally, the first part is located in the middle of the reference object.

可选的，所述第一部分包括全反射贴片，所述第二部分包括黑色泡棉。Optionally, the first part includes a total reflection patch, and the second part includes black foam.

可选的，所述参照物的第一坐标是根据所述激光雷达采集的点云中反射率高于阈值的目标点云点的坐标确定的。Optionally, the first coordinates of the reference object are determined according to coordinates of target point cloud points whose reflectivity is higher than a threshold in the point cloud collected by the lidar.

可选的，所述处理器在根据所述目标点云点的坐标确定所述参照物的第一坐标时用于：Optionally, when the processor determines the first coordinates of the reference object according to the coordinates of the target point cloud point:

根据点云点之间的距离对所述目标点云点进行聚类；Clustering the target point cloud points according to the distance between the point cloud points;

对聚类得到的每个类别分别确定中心点坐标，将所述类别的中心点坐标确定为所述参照物的第一坐标。The coordinates of the center point are respectively determined for each category obtained by clustering, and the coordinates of the center point of the category are determined as the first coordinates of the reference object.

可选的，所述参照物的数量为N，所述N为大于或等于3的整数。Optionally, the number of the reference objects is N, and N is an integer greater than or equal to 3.

可选的，N个所述参照物在所述激光雷达视场前的不同距离处形成至少2个参照物排。Optionally, the N reference objects form at least two reference object rows at different distances in front of the lidar field of view.

可选的，所述参照物排之间的参照物交叉排布。Optionally, the reference objects between the reference object rows are arranged crosswise.

可选的，N个所述参照物分布在所述激光雷达视场中的不同位置。Optionally, the N reference objects are distributed at different positions in the field of view of the lidar.

可选的，所述处理器在根据所述第一坐标和所述第二坐标，确定所述实际坐标系和所述设计坐标系之间的第一旋转矩阵时用于：Optionally, when determining the first rotation matrix between the actual coordinate system and the design coordinate system according to the first coordinate and the second coordinate, the processor is configured to:

根据所述第一坐标确定所述参照物在所述实际坐标系下的第一方向向量；determining the first direction vector of the reference object in the actual coordinate system according to the first coordinate;

根据所述第二坐标确定所述参照物在所述设计坐标系下的第二方向向量；determining a second direction vector of the reference object in the design coordinate system according to the second coordinate;

对所述第一方向向量和所述第二方向向量进行配准，得到所述第一旋转矩阵。The first direction vector and the second direction vector are registered to obtain the first rotation matrix.

可选的，所述激光雷达包括：非重复扫描激光雷达。Optionally, the lidar includes: a non-repetitive scanning lidar.

可选的，所述目标外参包括目标旋转矩阵和目标平移向量，所述目标旋转矩阵是所述第一旋转矩阵和所述设计外参中的设计旋转矩阵融合得到的，所述目标平移向量与所述设计外参中的设计平移向量相同。Optionally, the target external parameter includes a target rotation matrix and a target translation vector, the target rotation matrix is obtained by fusing the first rotation matrix and the design rotation matrix in the design external parameter, and the target translation vector The same as the design translation vector in the design extrinsic parameter.

可选的，搭载所述激光雷达的可移动平台包括无人车，所述可移动平台坐标系包括车身坐标系。Optionally, the movable platform carrying the lidar includes an unmanned vehicle, and the coordinate system of the movable platform includes a vehicle body coordinate system.

可选的，所述激光雷达的设计坐标系是所述激光雷达在设计的位置和设计的角度时对应的坐标系。Optionally, the design coordinate system of the laser radar is a coordinate system corresponding to the designed position and designed angle of the laser radar.

以上所提供的各种实施方式的外参标定装置，其具体实现可以参考前文中的相关说明，在此不再赘述。For the specific implementation of the external parameter calibration apparatuses of the various embodiments provided above, reference may be made to the relevant descriptions above, which will not be repeated here.

本申请实施例提供的外参标定装置，并不是直接求解激光雷达的实际坐标系和可移动平台的坐标系之间的转换关系，而是先考虑激光雷达的实际坐标系到设计坐标系之间的转换，再结合所述设计坐标系到可移动平台的坐标系之间的转换，最终得到目标外参。由于用于所述设计坐标系和可移动平台的坐标系之间转换的设计外参是已知且准确的，并且在所述实际坐标系和所述设计坐标系之间可以忽略平移向量，只确定旋转矩阵(第一旋转矩阵)，因此在整个目标外参的确定过程中，需要新确定的外参只有第一旋转矩阵，这一方面简化了计算流程，提高了计算效率，另一方面由于需要重新计算的外参少，因此在目标外参中引入的误差较小，提高了标定出的目标外参的准确度。The external parameter calibration device provided in the embodiment of the present application does not directly solve the conversion relationship between the actual coordinate system of the lidar and the coordinate system of the movable platform, but first considers the relationship between the actual coordinate system of the lidar and the design coordinate system The conversion between the design coordinate system and the coordinate system of the movable platform is combined with the conversion between the coordinate system of the movable platform, and the target external parameter is finally obtained. Since the design extrinsic parameters for conversion between the design coordinate system and the coordinate system of the movable platform are known and accurate, and the translation vector can be ignored between the actual coordinate system and the design coordinate system, only Determine the rotation matrix (the first rotation matrix), so in the whole process of determining the external parameters of the target, only the first rotation matrix needs to be newly determined for the external parameters, which simplifies the calculation process and improves the calculation efficiency. There are few external parameters that need to be recalculated, so the error introduced in the target external parameters is small, and the accuracy of the calibrated target external parameters is improved.

本申请实施例还提供了一种计算机可读存储介质，所述计算机可读存储介质存储有计算机程序，所述计算机程序被处理器执行时实现本申请实施例提供的外参标定方法。Embodiments of the present application further provide a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, implements the external parameter calibration method provided by the embodiments of the present application.

以上针对每个保护主题均提供了多种实施方式，在不存在冲突或矛盾的基础上，本领域技术人员可以根据实际情况自由对各种实施方式进行组合，由此构成各种不同的技术方案。而本申请文件限于篇幅，未能对所有组合而得的技术方案展开说明，但可以理解的是，这些未能展开的技术方案也属于本申请实施例公开的范围。Various implementations are provided above for each protection subject. On the basis of no conflict or contradiction, those skilled in the art can freely combine various implementations according to the actual situation, thereby forming various technical solutions. . However, this application document is limited in space and cannot describe all the technical solutions obtained by combination, but it can be understood that these technical solutions that cannot be developed also belong to the scope disclosed in the embodiments of this application.

本申请实施例可采用在一个或多个其中包含有程序代码的存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。计算机可用存储介质包括永久性和非永久性、可移动和非可移动媒体，可以由任何方法或技术来实现信息存储。信息可以是计算机可读指令、数据结构、程序的模块或其他数据。计算机的存储介质的例子包括但不限于：相变内存(PRAM)、静态随机存取存储器(SRAM)、动态随机存取存储器(DRAM)、其他类型的随机存取存储器(RAM)、只读存储器(ROM)、电可擦除可编程只读存储器(EEPROM)、快闪记忆体或其他内存技术、只读光盘只读存储器(CD-ROM)、数字多功能光盘(DVD)或其他光学存储、磁盒式磁带，磁带磁磁盘存储或其他磁性存储设备或任何其他非传输介质，可用于存储可以被计算设备访问的信息。Embodiments of the present application may take the form of a computer program product implemented on one or more storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having program code embodied therein. Computer-usable storage media includes both persistent and non-permanent, removable and non-removable media, and storage of information can be accomplished by any method or technology. Information may be computer readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), Flash Memory or other memory technology, Compact Disc Read Only Memory (CD-ROM), Digital Versatile Disc (DVD) or other optical storage, Magnetic tape cartridges, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission medium that can be used to store information that can be accessed by a computing device.

需要说明的是，在本文中，诸如第一和第二等之类的关系术语仅仅用来将一个实体或者操作与另一个实体或操作区分开来，而不一定要求或者暗示这些实体或操作之间存在任何这种实际的关系或者顺序。术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、物品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个……” 限定的要素，并不排除在包括所述要素的过程、方法、物品或者设备中还存在另外的相同要素。It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. The terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion such that a process, method, article or device comprising a list of elements includes not only those elements, but also other not expressly listed elements, or also include elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

以上对本发明实施例所提供的方法和装置进行了详细介绍，本文中应用了具体个例对本发明的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本发明的方法及其核心思想；同时，对于本领域的一般技术人员，依据本发明的思想，在具体实施方式及应用范围上均会有改变之处，综上所述，本说明书内容不应理解为对本发明的限制。The methods and devices provided by the embodiments of the present invention have been described in detail above. The principles and implementations of the present invention are described with specific examples in this paper. The descriptions of the above embodiments are only used to help understand the methods of the present invention and its implementation. At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. To sum up, the content of this description should not be construed as a limitation to the present invention. .

Claims

一种外参标定方法，其特征在于，包括：A kind of external parameter calibration method, is characterized in that, comprises:

获取参照物在激光雷达的实际坐标系下的第一坐标；Obtain the first coordinate of the reference object in the actual coordinate system of the lidar;

确定所述参照物在所述激光雷达的设计坐标系下的第二坐标；determining the second coordinate of the reference object in the design coordinate system of the lidar;

根据所述第一坐标和所述第二坐标，确定所述实际坐标系和所述设计坐标系之间的第一旋转矩阵；determining a first rotation matrix between the actual coordinate system and the design coordinate system according to the first coordinate and the second coordinate;

根据所述第一旋转矩阵和设计外参，确定所述实际坐标系和搭载所述激光雷达的可移动平台的坐标系之间的目标外参，所述设计外参是所述设计坐标系和所述可移动平台的坐标系之间的外参。According to the first rotation matrix and design extrinsic parameters, determine the target extrinsic parameters between the actual coordinate system and the coordinate system of the movable platform carrying the lidar, and the design extrinsic parameters are the design coordinate system and The extrinsic parameter between the coordinate systems of the movable platform.
根据权利要求1所述的方法，其特征在于，所述参照物在所述设计坐标系下的第二坐标是所述参照物在所述可移动平台的坐标系下的第三坐标通过所述设计外参转换得到的。The method according to claim 1, wherein the second coordinate of the reference object in the design coordinate system is the third coordinate of the reference object in the coordinate system of the movable platform passing through the The design extrinsic parameter conversion is obtained.
根据权利要求2所述的方法，其特征在于，所述参照物在所述可移动平台的坐标系下的第三坐标是利用测量设备测量得到的。The method according to claim 2, wherein the third coordinate of the reference object in the coordinate system of the movable platform is obtained by measuring using a measuring device.
根据权利要求3所述的方法，其特征在于，所述测量设备包括：全站仪或三维激光扫描仪。The method according to claim 3, wherein the measurement equipment comprises: a total station or a three-dimensional laser scanner.
根据权利要求1所述的方法，其特征在于，所述参照物包括第一部分和第二部分，所述第一部分的反射率高于所述第二部分的反射率。The method of claim 1, wherein the reference object comprises a first part and a second part, and the reflectivity of the first part is higher than the reflectivity of the second part.
根据权利要求5所述的方法，其特征在于，所述第一部分被所述第二部分包围。6. The method of claim 5, wherein the first portion is surrounded by the second portion.
根据权利要求6所述的方法，其特征在于，所述第一部分位于所述参照物的中部。The method of claim 6, wherein the first portion is located in the middle of the reference object.
根据权利要求5所述的方法，其特征在于，所述第一部分包括全反射贴片，所述第二部分包括黑色泡棉。6. The method of claim 5, wherein the first portion comprises a total reflection patch and the second portion comprises black foam.
根据权利要求5所述的方法，其特征在于，所述参照物的第一坐标是根据所述激光雷达采集的点云中反射率高于阈值的目标点云点的坐标确定的。The method according to claim 5, wherein the first coordinates of the reference object are determined according to the coordinates of the target point cloud points whose reflectivity is higher than a threshold in the point cloud collected by the lidar.
根据权利要求9所述的方法，其特征在于，根据所述目标点云点的坐标确定所述参照物的第一坐标，包括：The method according to claim 9, wherein determining the first coordinates of the reference object according to the coordinates of the target point cloud point comprises:

根据点云点之间的距离对所述目标点云点进行聚类；Clustering the target point cloud points according to the distance between the point cloud points;

对聚类得到的每个类别分别确定中心点坐标，将所述类别的中心点坐标确定为所述参照物的第一坐标。The coordinates of the center point are respectively determined for each category obtained by clustering, and the coordinates of the center point of the category are determined as the first coordinates of the reference object.
根据权利要求1所述的方法，其特征在于，所述参照物的数量为N，所述N 为大于或等于3的整数。The method according to claim 1, wherein the number of the reference objects is N, and the N is an integer greater than or equal to 3.
根据权利要求11所述的方法，其特征在于，N个所述参照物在所述激光雷达视场前的不同距离处形成至少2个参照物排。The method according to claim 11, wherein the N reference objects form at least two reference object rows at different distances in front of the lidar field of view.
根据权利要求12所述的方法，其特征在于，所述参照物排之间的参照物交叉排布。The method according to claim 12, wherein the reference objects between the reference object rows are arranged crosswise.
根据权利要求11所述的方法，其特征在于，N个所述参照物分布在所述激光雷达视场中的不同位置。The method according to claim 11, wherein the N reference objects are distributed at different positions in the field of view of the lidar.
根据权利要求1所述的方法，其特征在于，所述根据所述第一坐标和所述第二坐标，确定所述实际坐标系和所述设计坐标系之间的第一旋转矩阵，包括：The method according to claim 1, wherein the determining, according to the first coordinates and the second coordinates, a first rotation matrix between the actual coordinate system and the design coordinate system comprises:

根据所述第一坐标确定所述参照物在所述实际坐标系下的第一方向向量；determining the first direction vector of the reference object in the actual coordinate system according to the first coordinate;

根据所述第二坐标确定所述参照物在所述设计坐标系下的第二方向向量；determining a second direction vector of the reference object in the design coordinate system according to the second coordinate;

对所述第一方向向量和所述第二方向向量进行配准，得到所述第一旋转矩阵。The first direction vector and the second direction vector are registered to obtain the first rotation matrix.
根据权利要求1所述的方法，其特征在于，所述激光雷达包括：非重复扫描激光雷达。The method of claim 1, wherein the lidar comprises: a non-repetitive scanning lidar.
根据权利要求1所述的方法，其特征在于，所述目标外参包括目标旋转矩阵和目标平移向量，所述目标旋转矩阵是所述第一旋转矩阵和所述设计外参中的设计旋转矩阵融合得到的，所述目标平移向量与所述设计外参中的设计平移向量相同。The method according to claim 1, wherein the target external parameter comprises a target rotation matrix and a target translation vector, and the target rotation matrix is the first rotation matrix and the design rotation matrix in the design external parameter After fusion, the target translation vector is the same as the design translation vector in the design external parameter.
根据权利要求1所述的方法，其特征在于，搭载所述激光雷达的可移动平台包括无人车，所述可移动平台坐标系包括车身坐标系。The method according to claim 1, wherein the movable platform on which the lidar is mounted comprises an unmanned vehicle, and the coordinate system of the movable platform comprises a vehicle body coordinate system.
根据权利要求1所述的方法，其特征在于，所述激光雷达的设计坐标系是所述激光雷达在设计的位置和设计的角度时对应的坐标系。The method according to claim 1, wherein the design coordinate system of the laser radar is a coordinate system corresponding to the designed position and designed angle of the laser radar.
一种外参标定装置，其特征在于，包括：处理器和存储有计算机程序的存储器，所述处理器在执行所述计算机程序时实现以下步骤：A device for calibrating external parameters, comprising: a processor and a memory storing a computer program, wherein the processor implements the following steps when executing the computer program:

获取参照物在激光雷达的实际坐标系下的第一坐标；Obtain the first coordinate of the reference object in the actual coordinate system of the lidar;

确定所述参照物在所述激光雷达的设计坐标系下的第二坐标；determining the second coordinate of the reference object in the design coordinate system of the lidar;

根据所述第一坐标和所述第二坐标，确定所述实际坐标系和所述设计坐标系之间的第一旋转矩阵；determining a first rotation matrix between the actual coordinate system and the design coordinate system according to the first coordinate and the second coordinate;

根据所述第一旋转矩阵和设计外参，确定所述实际坐标系和搭载所述激光雷达的可移动平台的坐标系之间的目标外参，所述设计外参是所述设计坐标系和所述可移动平台的坐标系之间的外参。According to the first rotation matrix and design extrinsic parameters, the target extrinsic parameters between the actual coordinate system and the coordinate system of the movable platform carrying the lidar are determined, and the design extrinsic parameters are the design coordinate system and The extrinsic parameter between the coordinate systems of the movable platform.
根据权利要求20所述的装置，其特征在于，所述参照物在所述设计坐标系下的第二坐标是所述参照物在所述可移动平台的坐标系下的第三坐标通过所述设计外参转换得到的。The device according to claim 20, wherein the second coordinate of the reference object in the design coordinate system is the third coordinate of the reference object in the coordinate system of the movable platform passing through the It is obtained by converting the design external parameters.
根据权利要求21所述的装置，其特征在于，所述参照物在所述可移动平台的坐标系下的第三坐标是利用测量设备测量得到的。The apparatus according to claim 21, wherein the third coordinate of the reference object in the coordinate system of the movable platform is obtained by measuring using a measuring device.
根据权利要求22所述的装置，其特征在于，所述测量设备包括：全站仪或三维激光扫描仪。The apparatus according to claim 22, wherein the measurement equipment comprises: a total station or a three-dimensional laser scanner.
根据权利要求20所述的装置，其特征在于，所述参照物包括第一部分和第二部分，所述第一部分的反射率高于所述第二部分的反射率。21. The device of claim 20, wherein the reference object comprises a first portion and a second portion, and the reflectivity of the first portion is higher than the reflectivity of the second portion.
根据权利要求24所述的装置，其特征在于，所述第一部分被所述第二部分包围。25. The device of claim 24, wherein the first portion is surrounded by the second portion.
根据权利要求25所述的装置，其特征在于，所述第一部分位于所述参照物的中部。26. The device of claim 25, wherein the first portion is located in the middle of the reference.
根据权利要求24所述的装置，其特征在于，所述第一部分包括全反射贴片，所述第二部分包括黑色泡棉。25. The device of claim 24, wherein the first portion comprises a total reflection patch and the second portion comprises black foam.
根据权利要求24所述的装置，其特征在于，所述参照物的第一坐标是根据所述激光雷达采集的点云中反射率高于阈值的目标点云点的坐标确定的。The device according to claim 24, wherein the first coordinate of the reference object is determined according to the coordinate of the target point cloud point whose reflectivity is higher than a threshold in the point cloud collected by the lidar.
根据权利要求28所述的装置，其特征在于，所述处理器在根据所述目标点云点的坐标确定所述参照物的第一坐标时用于：The apparatus according to claim 28, wherein when the processor determines the first coordinates of the reference object according to the coordinates of the target point cloud points:

根据点云点之间的距离对所述目标点云点进行聚类；Clustering the target point cloud points according to the distance between the point cloud points;

对聚类得到的每个类别分别确定中心点坐标，将所述类别的中心点坐标确定为所述参照物的第一坐标。The coordinates of the center point are respectively determined for each category obtained by clustering, and the coordinates of the center point of the category are determined as the first coordinates of the reference object.
根据权利要求20所述的装置，其特征在于，所述参照物的数量为N，所述N为大于或等于3的整数。The device according to claim 20, wherein the number of the reference objects is N, and the N is an integer greater than or equal to 3.
根据权利要求30所述的装置，其特征在于，N个所述参照物在所述激光雷达视场前的不同距离处形成至少2个参照物排。The device according to claim 30, wherein the N reference objects form at least two reference object rows at different distances in front of the lidar field of view.
根据权利要求31所述的装置，其特征在于，所述参照物排之间的参照物交叉排布。The apparatus of claim 31 , wherein the reference objects between the reference object rows are arranged in a cross-arrangement.
根据权利要求30所述的装置，其特征在于，N个所述参照物分布在所述激光雷达视场中的不同位置。The apparatus according to claim 30, wherein the N reference objects are distributed at different positions in the field of view of the lidar.
根据权利要求20所述的装置，其特征在于，所述处理器在根据所述第一坐标和所述第二坐标，确定所述实际坐标系和所述设计坐标系之间的第一旋转矩阵时用于：The apparatus according to claim 20, wherein the processor determines a first rotation matrix between the actual coordinate system and the design coordinate system according to the first coordinate and the second coordinate When used for:

根据所述第一坐标确定所述参照物在所述实际坐标系下的第一方向向量；Determine the first direction vector of the reference object in the actual coordinate system according to the first coordinate;

根据所述第二坐标确定所述参照物在所述设计坐标系下的第二方向向量；determining a second direction vector of the reference object in the design coordinate system according to the second coordinate;

对所述第一方向向量和所述第二方向向量进行配准，得到所述第一旋转矩阵。The first direction vector and the second direction vector are registered to obtain the first rotation matrix.
根据权利要求20所述的装置，其特征在于，所述激光雷达包括：非重复扫描激光雷达。The apparatus of claim 20, wherein the lidar comprises: a non-repetitive scanning lidar.
根据权利要求20所述的装置，其特征在于，所述目标外参包括目标旋转矩阵和目标平移向量，所述目标旋转矩阵是所述第一旋转矩阵和所述设计外参中的设计旋转矩阵融合得到的，所述目标平移向量与所述设计外参中的设计平移向量相同。The apparatus according to claim 20, wherein the target external parameter comprises a target rotation matrix and a target translation vector, and the target rotation matrix is the first rotation matrix and the design rotation matrix in the design external parameter After fusion, the target translation vector is the same as the design translation vector in the design external parameter.
根据权利要求20所述的装置，其特征在于，搭载所述激光雷达的可移动平台包括无人车，所述可移动平台坐标系包括车身坐标系。The device according to claim 20, wherein the movable platform on which the lidar is mounted comprises an unmanned vehicle, and the coordinate system of the movable platform comprises a vehicle body coordinate system.
根据权利要求20所述的装置，其特征在于，所述激光雷达的设计坐标系是所述激光雷达在设计的位置和设计的角度时对应的坐标系。The device according to claim 20, wherein the design coordinate system of the laser radar is a coordinate system corresponding to the designed position and designed angle of the laser radar.
一种计算机可读存储介质，其特征在于，所述计算机可读存储介质存储有计算机程序，所述计算机程序被处理器执行时实现如权利要求1-19任一项所述的外参标定方法。A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the external parameter calibration method according to any one of claims 1-19 is realized .