Fast encoding algorithms for tree-structured vector quantization

摘要

To overcome extensive computations of searching codewords in the encoding process of vector quantization (VQ), several fast coding approaches has been proposed. As far as we know, the tree-structured search method is the fastest. In this paper, we further develop the encoding algorithm with fast search (EAWFS) and encoding algorithm with fast comparison (EAWFC) to speed up the encoding process of tree-structured vector quantization (TSVQ). These two approaches are also applicable to pruned tree-structured vector quantization (PTSVQ). The computational complexity of EAWFC is about half of that of the available method for TSVQ. For several encoded real images, EAWFS and EAWFC have a shorter execution time than that of the available algorithm. For images with a few edges, EAWFS will outperform EAWFC. EAWFS may theoretically obtain a lower distortion than that of the conventional method or EAWFC. However from our experiments, we have found that these three methods have the same distortion.