MODIFICATION TO SPIHT ALGORITHM USING INCREMENTAL THRESHOLD FOR IMAGE COMPRESSION

The Modified SPIHT represents a more efficient implementation of the SPIHT algorithm by using variable thresholds to sort the list of insignificant pixels (LIP) and the list of insignificant sets (LIS). We observe two interesting facts: (I) most of the initial subsets in LIS are not only insignificant with respect to the maximum threshold, but also insignificant with respect to the smaller threshold. And (2) Most of the pixels generating from sorting LIS are smaller than the current threshold. Based on these two observations, it represents a new image codec method, which can make the binary encoded outputs more efficient, and can work well on different image sizes and different decomposition levels.