New variable-rate VQ coding scheme apply in HDTV
Yushu Feng, Ker Zhang · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1990
In this paper, a new approach of a variable block size VQ coding scheme is proposed. Most natural image can be divided into regions of high and low detail. Traditional coding schemes do not adapt the blocksize on the space-varying characteristics of natural images, but break the image into blocks of a fixed size prior to processing. The blocksize in transform coding is usually too large to handle partial high-detail region satisfactorily. On the other hand, the block size in conventional vector quantizer is too small to take advantage of large homogeneous regions in an image. For this reason, it can be very attractive to implement a variable block size image coding scheme which allow a greater variation of the number of bits spent per unit area according to the local detail.