Subband coding of images using eigen designed quadrature mirror filters

This paper presents a multi-resolution image coding method for achieving high levels of compression. The multi-resolution subband decomposition system used is implemented with our “eigen designed quadrature-mirror filters”. Symmetric extension and windowing of the multi-scale subbands are incorporated to minimize the boundary effects. The Embedded Zerotree Wavelet (EZW) coding algorithm is then used for data compaction. Elimination of the isolated zero symbol for certain subbands, in fact, leads to an improved EZW algorithm. Additional compression is obtained with an adaptive arithmetic coder. For the Lena image we achieve a PSNR of 25.7 dB at a bit rate of 0.026, 31.1 dB at a bit rate of 0.137, and 38.7 dB at 0.89 bits/pixel