三目视觉图像的极线校正方法

Epipolar rectification in trinocular vision images

提出了解决垂直双基线三目(左、右、顶)极线校正的两步法。第一步摄像机旋转变换,按照特定的规则将各摄像机的对应坐标轴绕其光心旋转至互相平行,使得各像平面共面且与焦平面平行。第二步顶摄像机的平移变换,使三个摄像机光心构成空间等腰直角三角形。为此,提出一种等效处理方法。采用一面平面靶标,采集旋转变换前的三目图像,然后施以旋转变换,分析变换后三目图像所提供的特征对应点对的坐标,确定出顶图像变换至理想视图需要偏移的主点坐标,该过程等效于顶摄像机位置的平移。实验表明,该方法简便有效。

A two-step approach is proposed for the epipolar rectification of image triplet （left, right and top） in a perpendicular double-baseline vision system. Firstly, rotation transformations are made to the camera triplet. The axes of each camera coordinate frame are rotated around their optical centers until parallel, which insures that the retinal planes are coplanar and parallel to the focal plane. Secondly, a translational transform is conducted to the top camera so that the triplet of cameras is perfectly situated on the vertices of a isosceles right-angle triangle. For this purpose, an equivalent means in which a planar target is adopted, is proposed. Trinocular images of the planar grid are transformed with the rotational transformations obtained in first step. After analyzing the coordinates of corresponding points, the offset of principal point position, by which the top camera is rectified equivalently with optical displacement, is determined subsequently. Experimental results reveal the simplicity and effectiveness of this method.