基于两步法的摄像机标定算法

Camera Calibration Algorithm Based on Two-Step Methods

摄像机标定是机器视觉中的一个重要问题.精确的摄像机标定在涉及定量测量的应用中是非常重要的.摄像机标定的目的是得到摄像机的内部参数和外部参数.通过这些参数我们能够将一个点的三维位置与它的图像平面的坐标相匹配.本文提出了一种基于两步法的摄像机标定方法.第一步,使用基于无畸变的相机模型估计标定参数;第二步,在考虑相机畸变的情况下,对第一步中得到的标定参数通过非线性优化进行迭代优化,并求解畸变系数,包括径向畸变系数和切向畸变系数.用单幅图像即可完成标定,标定过程比两步法更为简洁.实验结果表明,这种算法是简单而有效的.

Calibration of cameras is considered as an important issue in machine vision.Accurate camera calibration is very important in the application of quantitative measurement.The objective of camera calibration is to obtain the internal and external parameters of each camera.With these parameters we can match the three-dimensional position of a point with the coordinates of its image plane.A camera calibration method based on the method of two-step technique is proposed in this paper.In the first step,the calibration parameters are estimated based on a distortion-free camera model.In the second step,considering the camera distortion,the calibration parameters obtained in the first step are iteratively optimized by nonlinear optimization,and the distortion coefficients,including the radial distortion coefficient and the tangential distortion coefficient,are solved.With a single image to complete the calibration,which is more concise than the two-step method.The experiments results illustrate that the algorithm is simple and effective.