圆球标定中相机外参数的几何解释和应用

Geometric Interpretations and Applications of the Extrinsic Parameters Derived from the Camera Calibration Based on Spheres

利用圆球进行相机标定的方法近年来得到深入研究.文中重新解释利用圆球进行相机标定时圆球投影与绝对二次曲线投影之间的几何关系,给出圆球与相机外参数之间关系的几何意义.提出一种利用矩阵正交分解求解球心参数的算法.与已有算法相比,该算法简洁、直观.进一步提出利用3个圆球求解相机外参数的算法.实验说明该算法精度高,可广泛应用于视觉平台中相机运动参数的求解.

Camera calibration based on spheres has been lucubrated in recent years. The geometric relationship between the projections of spheres and absolute conic （IAC） are reinterpreted in this paper. The geometric meaning between spheres and the extrinsic parameters is presented. A method for calculating the sphere centers based on the orthogonal decomposition is put forward. Compared with the existing methods, the proposed method is clear and simple. A method by using three spheres to calculate the camera extrinsic parameters is proposed as well. Experimental results show the two methods have high precision and can be widely applied in visual platform for parameters calculation of camera motion.