Improvements of the SPIHT for image coding by wavelet transform

The SPIHT (set partitioning in hierarchical trees) is an efficient image coding method using the wavelet transform. Two improvements of the SPIHT are presented in this paper. One is to use a new type of tree, to hold as many wavelet coefficients as possible during initialization. The other is to omit the predictable coding symbols for the significance indication of the coefficient sets or individual coefficients. The first improvement increases the compression ratio of low bit-rate image coding, while the second favours relatively high bit-rate image coding. The implementation of the SPIHT is re-designed to include the two improvements. The computation complexity is not increased by using these improvements. Simulation results show significant performance gain of the improvements