基于仿射点对应的分层重构

A Stratified Reconstruction Algorithm Based on Affine Point Correspondences

提出了一种基于仿射点对应的分层重构方法,所谓仿射点对应是指相差一个仿射变换的两个空间点集的图像对应.该方法主要分为以下三个步骤:首先,从点对应计算准仿射重构;然后,由仿射点对应的准仿射重构建立一个三维射影变换,并利用这个射影变换的特征向量来确定无穷远平面,从而得到仿射重构;最后,从仿射重构所获得的无穷远平面单应矩阵标定摄像机内参数,进而得到度量重构.在上述三个步骤中,第二个步骤是最关键的,即如何确定对应于无穷远平面的特征向量,这也是该文的新思想和主要贡献所在.仿真和真实图像实验均表明,该文的方法是有效的,并且有很好的鲁棒性.

In this paper, a new stratified reconstruction algorithm is proposed which is based on affine point correspondences. The affine point correspondences here mean image correspondences which are projected by two sets of space points related by a general 3D affine transformation. The proposed algorithm consists of the following three main steps： First, the quasi-affine reconstruction is obtained from correspondences of image points; Second, the 3D projective transformation matrix between the two sets of quasi-affinely reconstructed points in the first step is computed,then the eigenvector which corresponds to the plane at infinity is determined, by which the quasiaffine reconstruction is upgraded to a true affine reconstruction; Third, the camera intrinsic parameters are calibrated by means of the infinite homography obtained in the second step, and a metric reconstruction is obtained. Among the above three steps, the key one is the second step,i.e. , how to determine the eigenvector corresponding to the plane at infinity, and that is where the novelty and main contributions of this paper lie. Experiments on simulated data and on real images confirm the robustness of the new algorithm.