Spatiotemporal representation of dynamic objects

A new representation of dynamic scene objects to facilitate the compression and indexing of image sequences is presented. Exploiting the spatiotemporal (ST) piecewise-continuity of visual cues, the dynamic scene objects are represented as a collection of motion discontinuities. Each discontinuity signals either the start of a different motion or the occurrence of occlusion. It is shown that the sign of the Gaussian and mean curvature of the ST surfaces is sufficient for qualitatively representing the motion discontinuities. An estimation technique is developed to compute the sign of surface curvature from ST volume data, and the transformation rules that relate the image motion to the type of surface patch are described