Improved SPIHT Algorithm

An improved SPIHT algorithm that combines the SPIHT and the sub bands threshold calculation to reduce the number of comparison operations, without sacrificing the reconstructed image quality, is proposed. After applying discrete wavelet transform to the image, the threshold of each independent sub band is calculated. The scanning of the sets inside a sub band is determined by the magnitude of the thresholds that establish a hierarchical scanning not only for the set of coefficients with large magnitude, but also, for the sub bands. The proposed algorithm uses the set partitioning technique to sort the transformed coefficients. Results show that the proposed algorithm significantly reduces the number of comparison operations in the sorting passes while maintaining the visual quality and PSNR of the recovered image.