精密角度基准下的多相机定位系统高精度标定

High-Accuracy Calibration of Multi-Camera Positioning System Based on Precision Angle Reference

在视觉定位测量领域中的大尺寸测量、运动追踪、三维重建、视觉定位中,针对多相机定位系统中相机之间无公共视场或公共视场较小时系统标定困难、方法繁琐、精度低等问题,提出了一种基于精密二轴转台的多相机定位系统一体化标定方法。利用二轴转台提供角度基准,当转台一次转过所有相机视场时,各个相机依次拍摄标定图片,求解出各个相机内参以及各相机到转台的外参,利用转台坐标系中转计算相机之间的外参。整个标定过程由程序控制,实现了多相机系统采图标定的集成化、自动化,降低了标定工作量。分析了多相机定位系统的标定原理,并进行了实验验证。两相机内参重投影误差在0.17 pixel以内,系统定位精度在1 mm以内。结果表明,所提方法切实可行,精度较高,可操作性强,可应用于各种无公共视场或公共视场较小的多相机定位系统标定过程。

As for the large size measurement, motion tracking, 3 D reconstruction and visual positioning in the field of visual positioning measurement, there exist many problems of system calibration difficulty, method complexity,low precision and so on for a multi-camera positioning system with no public or less public field of view. Thus an integrated calibration method for a multi-camera positioning system is proposed based on a precision two-axis turntable, in which the two-axis turntable provides an angle reference. When the turntable passes through the fields of view of all cameras at once, each camera shoots sequentially the calibration images. The internal parameters of each camera and the external parameters from each camera to the turntable are solved. The turntable coordinates are used to calculate the external parameters of cameras. The whole calibration process is controlled by programming.The integration and automation of figure-collection calibration for the multi-camera system are achieved, which greatly reduces the workload of calibration. The calibration principle of this multi-camera positioning system is analyzed and verified by experiments as well. The reprojection errors of the internal parameters of two cameras are less than 0.17 pixel and the system positioning accuracy is less than 1 mm. The results show that the proposed method is feasible, accurate and operable, which can be applied in the calibration process of a multi-camera positioning system with no public or small public field of view.