An improved SPIHT algorithm based on wavelet coefficient blocks for image coding

An improved set partition in hierarchical trees (SPIHT) algorithm based on wavelet coefficient blocks is presented for image coding. According to the algorithm characteristic of traditional SPIHT that scanning once can process four wavelet coefficients, our approach is to divide the wavelet transform coefficient matrix into corresponding coefficient blocks and encodes every block with different strategy. When the maximum value of the coefficient block is less than the current threshold, only one bit is used for coding, thus to decrease the number of comparison and reduce the loss of coding efficiency caused by repeat coding and early coding for non-important coefficients. Analysis and simulation results show that the proposed algorithm can provide a better peak signal to noise ratio performance at low bit rate.