Fast omni-image unwarping using pano-mapping pointers array

Omni-cameras are becoming ubiquitous in several applications that require a wide field of view (such as 3D reconstruction, video surveillance, robot vision, etc.) and thus the need to reduce computational time during omni-image un-warping. In this paper a computationally efficient alternative referred as pano-mapping pointers array (PMPA) is proposed. First, a buffer is created to save the omni-image. Then, a PMPA is created, where each entry points to a specific place in the buffer depending on the interpolation desired (nearest neighbors or bilinear interpolation). Finally, using the PMPA we unwarp the omni-image. The PMPA is created once for an omni-camera, interpolation method and panoramic image resolution. Experiments on a standard computer demonstrate that the proposed method is about 5.8 (nearest neighbors) and 2.1 (bilinear interpolation) times faster than the classic pano-mapping table method and about 1.7 (nearest neighbors) times faster than the one-eighth pano-mapping table method.