单像空间后方交会算法的研究

A New Algorithm for Single Image Space Based Resection

采用单像空间后方交会算法求解相机的外参数是摄影测量及机器视觉等领域的基本问题。在介绍前人研究成果的基础上,提出一种新的单像空间后方交会算法,即利用3个控制点建立临时坐标系,根据这些控制点在临时坐标系下的部分坐标分量为0的特点,将后方交会求解转换为三元二次方程组的求解,3个控制点的图像坐标数据可为非线性方程组的迭代求解提供初始值,使求解过程更加可靠。利用某商用工业摄影测量系统对实验空间中布设的控制场拍摄了120幅图像并计算其外参数,采用后方交会算法和角锥体算法分别对所取特征点计算外参数,结果表明:后方交会算法求解的参数正确,且迭代求解收敛性好,适用于任意旋转角的相机外参数求解。

Solving the camera external parameters with single image space resection algorithm is a fundamental problem in the fields of photogrammetry and machine vision.Based on the previous work,a new robust algorithm is presented in this paper.A temporary coordinate system is created by three control points.Due to part of the coordinate component of these control points in the temporary coordinate system being zero,the resection solving is transformed to the solution of ternary quadratic equations,the initialize solutions for the nonlinear equations can be acquired by the image coordinates of the three points,which makes the solving process more reliable.In the experiment,120 images of the control field are taken by the commercial industrial photogrammetry system and the external parameters are calculated with the proposed resection algorithm and the pyramid algorithm.Experimental results illustrate that the parameters calculated by the proposed resection algorithm are correct,and the convergence is good,showing that the proposed algorithm is suitable for solving external parameters of cameras with arbitrary rotation angles.