Realtime IBR with omnidirectional crossed-slits projection

The crossed-slits (X-Slits) projection can be used to generate new views of a scene from a sequence of perspective images. Compared with other image-based rendering (IBR) techniques, X-Slits image generation is simple and requires a relatively small number of input images, which makes it suitable for realtime IBR. In this paper we extend this model to omnidirectional cameras and a circular slit. We show how it can be used for realtime image-based rendering of omnidirectional images, and how to optimize it for speed and quality. We analyze the inherent geometric distortions of the circular X-Slits projection, and describe a normalization mechanism to reduce distortions, creating a realistic virtual environment. Essentially the same mechanism is used to augment the X-Slits images with artificial objects, when using standard graphics tools which assume perspective projection.