一种基于立体标定件的双摄像机外参数标定法

对于应用于现场测量的立体视觉测量系统,两摄像机间的外参数标定是保证系统测量准确度的重要环节之一。介绍了一种利用立体标定件实现系统外参数标定的方法,其特点是只要两摄像机同时拍摄一幅标定件图像,利用标定件上的球形特征点与其成像点之间的共线性约束建立共线性标定方程组,通过Levenberg-Mar-quardt迭代优化算法分别确定两摄像机与世界坐标系的关系,最后利用世界坐标系作为中介,将两摄像机间的外参数求出。同传统标定方法相比,该方法简单、快捷,鲁棒性好,可用于现场标定。

External Parameter Calibration of Two Cameras Based on Three-dimensional Calibration Object

For field stereo vision measurement system, the external parameter calibration of two cameras is one of the important steps, which ensure the system measurement accuracy. A three-dimensional calibration object-based method is presented in this paper. The technique only requires each camera take photograph of calibration object at the same time. And then, overdetermined collinear equations can be established according to collinear constraint between the sphere spatial points and their imaging points. Moreover, using Levenberg-Marquardt iteration optimization, the relationship between each camera and world coordinates is determined. At last, the external parameters can be accurately calibrated through the world coordinates. Compared with classical techniques, the proposed operation is easy and simple, the algorithm is robust, and so it can be applied in field calibration.