A LOW BIT RATIO IMAGE CODING SCHEME BASED ON WAVELET TRANSFORM

A still image coding scheme based on wavelet transform was proposed. The image wasdecomposed by discrete wavelet transform, the detail subimages were encoded by classified vectorquantization and the coding information of the lowest resolution subimages was only used fordecoding according to the similarity among different resolution subimages with the same orientation. Thelow resolution coarse approximation subimage was encoded by DPCM and entropy coding. Highspeed and high compression ratio under the good visual quality were obtained with our proposedscheme. Compared with the published schemes,author's scheme performs better.