Low resolution region discriminator for wavelet coding

A wavelet block chain (WBC) method is used in the initial coding of the low -low subband created by a wavelet transform to separate and label homogenou s regions of the image which require no additional overhead in the bitstrea m. This information is then used to enhance the coding performance in a mod ified wavelet based coder. This method uses a two stage ZTE/SPIHT entropy c oder (called a homogenous connected-region interested ordered transmission coder) to create a bitstream with properties of progressive transmission, s calability, and perceptual optimisation after a minimum bit rate is reached . Simulation results show good scalable low bit rate (0.04-0.4bpp) compress ion, comparable to a SPIHT coder, but with better perceptual quality due to use of the region based information acquired by the WBC method.