Rectified catadioptric stereo sensors

It has been previously shown how mirrors can be used to capture stereo images with a single camera, an approach termed catadioptric stereo. In this paper we present novel catadioptric sensors which use mirrors to produce rectified stereo images. The scan-line correspondence of these images benefits real-time stereo by avoiding the computational cost and image degradation due to resampling when rectification is performed after image capture. First, we develop a theory which determines the number of mirrors that must be used and the constraints on those mirrors that must be satisfied to obtain rectified stereo images with a single camera. Then we discuss in detail the use of both one and three mirrors. In addition, we show how the mirrors should be placed in order to minimize sensor size for a given baseline, an important design consideration.