Lossless Wavelet Based Image Compression with Adaptive 2D Decomposition

2D wavelets are usually generated from 1D wavelets through the rectangular or through the square decomposition scheme. In this paper a new adaptive 2D decomposition scheme for compression related applications is presented. The adaptive 2D decomposition selects 2D wavelet functions based on the compression of the coefficients, but needs only the same number of 1D filter operations as the rectangular decomposition for the compression and even less for the decompression. Results for lossless image compression have shown improvements in the compression rate between 1% and 10% compared to the square decomposition. Only in the case of very small images (below 50x50) the adaptive decomposition was outperformed by the square decomposition because of the overhead to store the selection, which 2D wavelets should be used.