视觉传感器的外参标定旨在建立视觉坐标系与外部标准坐标系之间的关系。设计了视觉测量合作靶球以实现视觉测量与仪器测量之间的合作测量。通过将视觉测量合作靶球与激光跟踪仪靶镜相互替换获取公共点在视觉坐标系和外部标准坐标系下的坐标,并利用公共点在两坐标系下的坐标对目标函数进行非线性优化,获得视觉传感器外参数最优解。视觉测量合作靶球的设计将靶标、光源和球形外壳相融合,以满足与跟踪仪合作靶镜的互换性和球心可测的需求。对外参标定过程中的误差传递进行了分析,并通过仿真优化标定精度,以及实验验证该标定方法的精度。结果表明,该方法的外参标定精度可达到0.036 mm,能够实现直接、灵活、高精度的公共点数据获取。

The aim of extrinsic parameter calibration is to build the relationship between vision coordinate system and extrinsic standard coordinate system. The substitutable target sphere for vision-measurement is designed to cooperate the vision-measurement and instrument measurement. The vision-measurement target sphere and the equipment-measurement target sphere replace each other to get the coordinate of common points in both vision coordinate and standard coordinate. And the extrinsic parameters are solved by optimizing the target function with the coordinate of common points in both systems using non-linear optimization method. The design of substitutable vision-measurement target sphere consists of target, light source and sphere shell to satisfy the substitutability with equipment-measurement target sphere and the availability of center of sphere. The propagation of error during the calibration is presented. The accuracy of calibration is promoted through simulation and verified by experiment. The result shows that the accuracy reaches 0.036 mm, which shows that the proposed method can realize public point data acquisition directly, flexibly and high-accuracyly.