Scan interleaving based scalable binary shape coding

In this paper, we propose scan interleaving based shape coding (SISC) as a spatial scalable coding algorithm for binary shape. A typical scalable video system has two or more scalable layers. These are the base layer and the associated enhancement layers. In the proposed spatial scalable binary shape coding algorithm, scan interleaving based data encoding (SI) scheme is proposed for the enhancement layer coding. And context-based arithmetic encoding (CAE) method is employed for entropy coding of binary shape data in each scalable layer. SI scheme efficiently exploits the spatial redundancy of the scalable layers. For reducing the temporal redundancy, inter-frame coding based on motion compensation is employed. The major advantages of SISC are high coding gain, low complexity, and consistency with MPEG-4 non-scalable binary shape coding. High coding gain is achieved from the method of coded-scan-line data analysis, which uses exclusive-OR operation on top and bottom reference pixels. Furthermore, by referring the lower layer motion vectors for its inter-frame coding process, SISC also saves some computational overhead of enhancement layer coding. The proposed technique is, currently, adopted in the Working Draft of MPEG-4 Version 2. SISC supports both the frame-based coding mode and the block-based coding mode. The block-based SISC, as in MPEG-4, is mainly described in this paper.