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室内移动测图平台的多传感器联合标定
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Abstract:
室内移动测图平台集成多目相机、二维激光扫描仪等多种传感器，用以实现室内的高精度定位及三维空间数据获取。精确标定出传感器的外参数，实现传感器空间基准统一，这是多传感器数据有效利用的基础，也是室内测图平台相关研究的重点问题之一。本文提出一种便捷的多目相机及二维扫描仪的标定方法，首先，在平台上布设控制，建立机身坐标系。然后在相机与扫描仪的有效视场分别布设黑白靶标、靶球作为公共点，借助于高精度三维激光扫描仪获取公共点在机身坐标系中坐标值。接着使用EPNP算法进行相机的标定，圆拟合的方法实现扫描仪标定，获取传感器在机身坐标系下外参数。最后对标定实验结果进行精度验证，相机标定重投影误差低于1个像素，扫描仪标定结果优于1厘米。
Multi LiDAR-camera is integrated on the indoor mapping robotic system for mission of high-precision positioning and three-dimensional spatial data acquisition. Accurate extrinsic calibration of sensors is the basis of effective utilization of multi-sensors data, and is also one of key issues of indoor mobile mapping research. This paper presents a convenient calibration method for multi-sensors. First, some control points are laid on the body of the robot to create the robot body coordinate system. Then, several identifiable targets are fixed in the effective field of view of LiDAR and camera. The coordinate value of targets in the robot body coordinate system is obtained by three-dimensional laser scanner. Finally, EPNP algorithm is used to calculate the extrinsic of camera based on the corresponding relationship between two-dimensional points and three-dimensional points, and RANSAC circle fitting is used to calibrate the 2D LiDAR. Experiments show that the camera reprojection error is less than 1 pixel and the calibration result of 2D LiDAR is better than 1 cm.
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