Quadtree based classification with arithmetic and trellis coded quantization for subband image coding

In this a paper a quadtree based method is proposed for classifying blocks of samples in image subbands. Classi cation of blocks of subband samples according to their energy and variable bit allocation within the subsequent classes has demonstrated considerable gains in coding e ciency. The gains due to classi cation increase as smaller blocks are used; however, so do the overheads for transmitting the classi cation information. The quadtree based method proposed in this paper allows for more e cient classi cation by using variable-sized blocks in order to maximize the classication gain, while maintaining a limit on the classi cation overheads. Using an e cient quantization scheme such as ACTCQ [5] (Arithmetic and Trellis Coded Quantization), we have been able to demonstrate competitive coding results at low bit-rates.