Modified tree structure for transform vector quantization

In this paper, we present a modified image format which is appropriate for transform vector quantization. Based on tree structure, this format can adopt itself to the detail in image with small overhead. Compared to conventional quadtree structure, the proposed technique provides a simpler structure because of its constant output size. This benefit comes from the subsampling process of the normal tree structure. The unique characteristic of a new format combining with the strength of transform vector quantization improves coding gain of the proposed system. Simulation results in terms of objective criteria are also given to illustrate this improvement