Calibration of omnidirectional stereo for mobile robots

Abstract

This paper describes a calibration method of an omnidirectional stereo system. The system uses a pair of vertically-aligned catadioptric omnidirectional cameras, each of which is composed of a perspective camera and a hyperboloidal mirror, thus providing a single projection point. We divide the calibration into two steps. The first step estimates the image center and the aspect ratio by fitting an ellipse to the mirror boundary in the image. The second step estimates the focal length and the camera pose (position and orientation) including scale by using a calibration pattern and epipolar geometry. Experimental results show the effectiveness of the proposed calibration method.