地面三维激光扫描仪与外架数码相机间安置参数的高精度标定

提出了地面三维激光扫描仪与外置数码相机安置参数的高精度标定方案。首先,利用商业化近景摄影测量系统对相机内参数进行单独标定;然后,利用回光反射标志作为二维和三维匹配的同名控制点,对直接线性变换进行拓展应用,在算法迭代过程将内参数作为已知值对外参数进行求解;最后,根据相机数据采集特点确定其拍摄全景时多张影像之间的位置关系,对多张影像的外方位元素进行求解,从而实现全景点云与全景完整影像之间的映射。进行了实验测试,利用安置参数标定结果反求验证点像素坐标与真实测量结果之差验证了本文标定方法的精度和可行性。实验显示:点云与影像间的映射精度可达到1像素左右;相机拍摄全景获取的影像与全景点云可以实现正确映射,表明提出的标定方法正确,满足纹理贴图及将影像作为特征提取辅助信息的精度要求。

High accuracy calibration of installation parameters between 3D terrestrial laser scanner and external-installed digital camera

A high accuracy calibration method for the installation parameters between 3D Terrestrial Laser Scanner(TLS) and external-installed digital camera was proposed. Firstly, the intrinsic parameters were calibrated by existing commercialized close-range photogrammetry products. Then,by taking reflector target centers as input control points of 2D and 3D matching, the direct linear transformation algorithm was expanded in applications and the intrinsic parameters were taken as known coefficients to solve the extrinsic parameters. Finally, the extrinsic parameter of every camera shooting angle was calculated according to the relationships between different shooting angles to get the mapping relationship between point cloud and multi-angle images. The test experiments were performed, and the accuracy and feasibility of the calibration method were verified by obtaining the difference between point pixel coordinate and real measuring result with installation parameter calibration results. The experimental results indicate that the calibration accuracy reaches 1 pixel and the mapping relationship between point cloud and multi-angle images is correct, which satisfies the requirements of texture mapping and accuracy by applying images as auxiliary data in feature extraction.