LOSSLESS REGIONS OF INTEREST AND ADAPTIVE WAVELET COMPRESSION OF BACKGROUND
Waldemar Rakowski · 2001
A new compression scheme of images with lossless coding for Regions Of Interest (ROI) is developed. It is based on adaptive quantisation scheme in wavelet transform domain. The ROIs are encoded by the lossless JPEG-LS method. The background is encoded by embedded (SPIHT-based) wavelet method. The ROIs can have arbitrary shape. A mask indicating a set of wavelet coefficients corresponding to ROIs is obtained by adequatly defined control low pass filters. Zeroing wavelet coefficients indicating by the mask increases the number of zerotrees in SPIHT coding, and therefore one can expect higher coder’s bitrate. Numerical results to illustrate the performance of the proposed algorithm are provided.