Low resolution region discriminator for waveletcoding
Yasser F. Syed, K.R. Rao · Electronics Letters · 2001
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 homogenous regions of the image which require no additional overhead in the bitstream. This information is then used to enhance the coding performance in a modified wavelet based coder. This method uses a two stage ZTE/SPIHT entropy coder (called a homogenous connected-region interested ordered transmission coder) to create a bitstream with properties of progressive transmission, scalability, and perceptual optimisation after a minimum bit rate is reached. Simulation results show good scalable low bit rate (0.04–0.4 bpp) compression, comparable to a SPIHT coder, but with better perceptual quality due to use of the region based information acquired by the WBC method.