Adaptive contour sampling and coding using skeleton and curvature

This paper presents a new binary shape sampling and coding method. Within the framework of the MPEG-4 standard, the binary shapes in video object plans have to be coded with a near to lossless approach in order to obtain a perfect spatial and temporal localization. For this purpose, a new sampling method based on the object skeleton is developed. The "r-sampling" is defined function of the local feature size (LFS) which is the distance between a shape point and the closest point on the medial axis of this shape. A weighting convex function φ depending on the local curvature is also introduced to increase the local adaptiveness of the sampling ("the r&c-sampling"). This new approach is tested on contours presenting high level details. The first results obtained are satisfactory in terms of both the reduction of samples and the reconstruction error.