METHOD AND SYSTEM FOR ACHIEVING CODING GAINS IN WAVELET-BASED IMAGE CODECS

摘要

A method and system for coding a RGB image in an encoder and a decoder. In the encoder, the RGB image components are converted into YUV components. One or more of the lower bit-planes of YUV components are eliminated before the YUV components are transformed by forward wavelet transform and coded into a codestream for transmission. In the decoder, the codestream is decoded and transformed by inverse wavelet transform into a set of reconstructed YUV components. The bit-planes of these reconstructed YUV components are up-shifted so that the up-shifted YUV components are structurally equivalent to the original YUV components before they are adjusted in the encoder. However, the lower bit-planes that come into being due to the up-shifting are all set to zero. The up-shifted YUV components are then converted into the RGB component of the reconstructed image.