A vector quantizer with increased codebook patterns

In this paper, we present an approach to increase the amount of VQ codebook patterns to improve image quality without a large overhead on the memory and search time. Basically, our approach characterizes a pattern into a key value, which is used in codebook search; the "reflection operation" was performed on codewords using the key values to get more patterns to improve image quality. Our basic VQ system is a 2-step VQ where VQ is used to compress prediction errors resulting from simple scalar quantization of pixel blocks. The codebook search time for our technique is O(logN+K) for each input vector, where N is the codebook size and K is the Voronoi range. Experimental results are presented in the paper.