基于平面靶标的相机内部参数标定精度分析

相机内部参数标定是实现机器视觉测量的必要环节.目前常用的标定方法有Tsai两步法、DLT方法以及基于平面标靶的张正友法等.张正友法简单易行,因而得到广泛应用,标定精度取决于平面靶标的制作精度、图像特征点坐标的提取精度、镜头畸变、靶标摆放数目以及位姿分布等.对张正友标定方法的精度进行探讨,分析各影响因素对标定精度的影响,提出基于均匀设计的思想进行靶标位姿分布的设计思想.仿真和实际测试证明,采用均匀设计的靶标布局明显提高相机内部参数标定精度.

Camera internal-parameters calibration of accuracy of analysis based on planar target

The camera interior parameters calibration is a necessary part of machine vision measurement. The existing calibration methods, include Tsai two-step method, DLT method as well as method of Zhang Zheng-you based on planar target are frequently used. Among them, Zhang method is widely used due to its high implementability, however, its calibration precision depends on the precisions of manufacturing target plane, image feature point extraction, lens distortion, and the number and distribution of target pose. Aiming at the problems, based on the analyze of the impact of each factor on the calibration precision by the Zhang calibration method. A camera calibration method, which was uniform design idea applied in position and orientation distribution of target was proposed. The result of simulation and actual measurement shows that the proposed calibration method significantly improve the accuracy of the camera interior parameters.