基于相位匹配的大视场视觉检测系统

针对三维测量大量程和高精度测量问题,提出一种新型双目视觉检测系统.该系统通过向被测物投射间距可变的光栅条纹,将不同曲率的被测表面进行相位编码,由相位匹配得到被测物稠密的立体匹配点云;再由标定出的摄像机内外参数计算出被测物的精确三维坐标.为了解决传感器单元测量区域较小的问题,系统通过步进电机控制传感器移动,获取大型物体的全场三维数据点云;最后利用四元素法,实现大型物体的三维数据拼接.该系统长度测量标准差为36?μm,角度测量与坐标测量机(CMM)测量结果的相对误差0.2％.给出了某V型面三维实测的数据重建结果.对某大型特件(360?mm×300?mm)经过三维拼接正确复现了其三维形貌.该系统对于解决大型构件三维形貌的在线高精度检测问题具有较高工程应用价值.

Novel vision system for large field inspection based on phase matching

To solve the problem of large scale three-dimensional (3D) measurement with high accuracy, a new binocular stereo vision inspection system was presented. By projecting variable period fringes, the surface with different curvature was coded with phase. The stereo matching points were determined using phase matching technique, so that dense 3D coordinate points could be calculated by the intrinsic and extrinsic parameters of the calibrated cameras. In order to solve the problem of small measurement field of sensor unit, the vision sensor scanned the whole surface of a large object under a step motor’s control, then quaternion was used to realize 3D registration. The sensor’s standard deviation in length measurement is 36?μm, and the relative error of angular measurement is 0.2% compared with the CMM(coordinate measuring machine). The 3D integration of a large object (360?mm×360?mm) is given correctly.The vision system is of great engineering value in large 3D non-contact online measurement with high accuracy.