DECOMPOSITION OF HIGH-BAND SIGNALS IN A REVERSIBLE SUBBAND CODING BY USING SIMILARITY OF BANDS

This paper points out problems in the reversible subband coding, toget her with the means to overcome the problems. It is shown for the rever sible subband coding that there exists a redundancy between the subban d signals, and that the reduction of the information is less in the su bband decomposition of the high-band signal. In the proposed system, s ubband decomposition is not applied to the high-band signal, but the h igh-band signal is decomposed based on the similarity between subband signals. More precisely, the already reconstructed image with low reso lution is decomposed according to the magnitude of the pixel value gra dient, and the high-band signal is correspondingly decomposed. By such a decomposition method, it is made possible to transmit and display t he signals from more important components. Then, it is expected that t he compression efficiency is improved and that the psychological burde n in successive image display can be reduced. It is shown by simulatio n that the compression efficiency is improved in lossless reconstructi on and in progressive image reconstruction. (C) 1997 Scripta Technica, Inc.