Multi-grid chain coding of binary shapes

This paper presents a chain code based approach to efficiently code binary shape information of video objects, in the context of object-based video coding. The proposed method tries to meet some of the requirements of the MPEG-4 standard, currently under development, notably efficient coding, and low delay. This approach allows several modes of operation depending on the application requirements, notably lossless, near-lossless, and lossy coding modes. For the lossless case a pure differential chain code method is proposed while for the near-lossless case a multi-grid chain code (MGCC) technique is adopted. Also both INTRA and INTER prediction modes can be used. For the INTER mode, motion compensation is applied without coding the residues. The MGCC is a near-lossless contour coding technique using a contour description based on edges, which combines both contour prediction and contour simplification.