VECTOR QUANTIZATION OF IMAGE SUBBANDS - A SURVEY

Subband and wavelet decompositions are powerful tools in image coding because of their decorrelating effects on image pixels, the concentrat ion of energy in a few coefficients, their multirate/multiresolution f ramework, and their frequency splitting, which allows for efficient co ding matched to the statistics of each frequency band and to the chara cteristics of the human visual system, Vector quantization (VQ) provid es a means of converting the decomposed signal into bits in a manner t hat takes advantage of remaining inter and intraband correlation as we ll as of the more flexible partitions of higher dimensional vector spa ces, Since 1988, a growing body of research has examined the use of VQ for subband/wavelet transform coefficients, We present a survey of th ese methods.