Lossless image coding using wavelets and variable block size segmentation

We propose a lossless image compression scheme using wavelet decomposition. Wavelet decomposition of an image f(x,y) at a resolution 2^j consists of an approximated image at a resolution 2^j-1 and three detail images along the horizontal, vertical and diagonal directions. The approximated wavelet coefficients are encoded using a variable block size segmentation (VBSS) algorithm proposed by Ranganathan et.al. (see IEEE Trans. on Image Proc., vol.4, no.10,p.1396-1406, 1995) and the detail signals are encoded using directional prediction and categorization similar to that in the VBSSS algorithm. The residual error due to the finite precision arithmetic is encoded using adaptive arithmetic coding (AAC). The performance of the proposed approach is comparable to that exhibited by JPEG lossless schemes while being better than the Huffman, the Lempe-Ziv and arithmetic coding