多目视觉测量系统的光束法平差改进

为了消除三维扫描测量机器人系统中工业机器人定位误差对测量结果的不利影响，搭建了多目视觉测量系统对三维扫描测头进行空间同步定位。由于系统中相机与标志点之间的距离变化较大，标志点重投影误差难以评价空间定位误差，另外受相机标定精度影响，光束法平差对三维坐标修正不明显。为解决上述问题，本文改进了光束法平差，在传统光束法平差的误差方程中引入摄影比例尺，再将整体参数的优化分为两步，先修正相机内、外参数，再修正被测点三维坐标，以提升系统的三维重建精度。实验结果表明，在对一维基准尺长度的测量实验中，测量结果与参考值之间的偏差小于0.300 mm，标准差不大于0.110 mm，满足三维扫描测量机器人系统的应用需求。

Improvement of Bundle Adjustment in Multiocular Vision Measurement Systems

In order to eliminate the negative influence of positioning errors of industrial robots on measurement results in 3D robotic scanners, a multiocular vision measurement system is set up to locate the 3D scanning probe. In the multiocular vision measurement system, due to the large change in the distance between the camera and the marker, the reprojection error of the marker is difficult to evaluate the spatial positioning error. In addition, due to the influence of the camera calibration accuracy, the correction of the 3D coordinate by the bundle adjustment is not obvious. The bundle adjustment method is improved in this paper to improve the 3D reconstruction accuracy of the system. The image scale is introduced into the error equation of the traditional bundle adjustment method. The optimization of overall parameters is implemented in two steps based on the new error equation. Firstly, the intrinsic and extrinsic parameters of the camera are corrected, then the 3D coordinates of the measured point are corrected. The experimental results show that, in the measurement experiment of the length of the Creaform scale bar, the deviation between the measurement result and the reference value is less than 0.300 mm, and the standard deviation is not bigger than 0.110 mm, which fulfill the application requirements of the 3D robotic scanner.