Quad-tree-based image shape coding with block compensation

Image shape coding is a core technique in MPEG-4. In the paper, we present a quad-tree-based technique for image object shape coding. Quad tree has been used to represent the image content since long time ago, it describes the hierarchy of various sizes of rectangular blocks that collectively constitute the image object area. Quad tree structure can be quite complicate to describe an image object with unsmooth boundary. We propose a block compensation and a run-length scheme to effectively attack the problem. Experimental results show that the algorithm is quite efficient in comparison with other methods.