A novel rectification framework for coaxial omni-directional stereo

Epipolar rectification greatly simplifies the stereo matching which is important for vision based robotics navigation. In this paper we propose a novel rectification algorithm for coaxial omni-directional stereo system, i.e. systems aligned on the same axis of symmetry. The essential matrix is derived and computed for an arbitrary omni-directional stereo configuration based on Taylor model firstly. Using the one-to-one corresponding relationship between epipolar curve and its tangential space, we rectify the system to the direction of the line connecting two cameras´ centers. This step removes the translation misalignment. After that, the corresponding points are constraint to the radial line. Image-resample based on the essential matrix compensates the rotation misalignment and makes corresponding points lie on the same scan column. The proposed algorithm is only performed on image plane so that the computation time and error caused by multi-projections in 3D space are decreased. Finally, experimental results on simulation and real data illustrate the effectiveness and accuracy of our algorithm.