WAVELET TRANSFORMS THAT MAP INTEGERS TO INTEGERS

Invertible wavelet transforms that map integers to integers have impor tant applications in lossless coding. In this paper we present two app roaches to build integer to integer wavelet transforms. The first appr oach is to adapt the precoder of Laroia et al, which is used in inform ation transmission; we combine it with expansion factors for the high and low pass band in subband filtering. The second approach builds upo n the idea of factoring wavelet transforms into so-called lifting step s. This allows the construction of an integer version of every wavelet transform. Finally, we use these approaches in a lossless image coder and compare the results to those given in the literature. (C) 1998 Ac ademic Press.