Binocular Spherical Stereo

A fish-eye camera has a wide field of view (FOV), and the realization of a binocular fish-eye stereo for sensing the surrounding 3-D information of the environment around a vehicle is useful for safe driving. However, since a fish-eye camera may have a wider-than-hemispherical FOV, the conventional stereo approach of obtaining a perspective image based on the pinhole camera model cannot directly be applied. However, using a spherical camera model and defining the disparity of a spherical stereo, the conventional binocular stereo problem is reformulated as a binocular spherical stereo problem. A binocular spherical stereo is a generalized paradigm that can cope with cameras having any FOV, including conventional cameras and fish-eye cameras. Moreover, by transforming the rectified spherical images to latitude-longitude representation, the feature point matching of the spherical stereo images can be sped up by using the processing used for perspective stereo images. The effectiveness of this approach is demonstrated by realizing a binocular spherical stereo using a pair of fish-eye cameras. Finally, the application of the proposed approach to vehicles in the future is considered.