Block Tree Partitioning for Wavelet Based Color Image Compression

This paper presents a new algorithm for wavelet based image compression by exploiting zero tree concept in the wavelet decomposed image. The algorithm has a big edge over previously developed wavelet based image compression algorithms in that it utilizes inter and intra band correlation simultaneously, something that previous algorithms failed to exploit. Besides the improvement in coding efficiency, the algorithm also uses significantly lower memory for computation and coding thereby reducing the complexity of the algorithm. The striking feature of the algorithm is pass independent coding that makes it suitable for application to error protection schemes and makes it less vulnerable to data loss due to noisy communication channel. The algorithm codes all the color bands independently thus enabling differential coding for the color information. The paper starts with the discussion of the concept underlying the algorithm and then sees the algorithm in a broader light. Comparisons have been made to SPIHT, the well known zero tree coder for wavelet based image compression in terms of coding efficiency, memory requirements and error resiliency.