Runlength-based wavelet coding with adaptive scanning for low bit rate environment

A new wavelet image coding method is presented to exploit both intra/inter-band correlations. While the traditional zerotree approach can exploit correlation between subbands, a wavelet decomposition has properties more suitable for the runlength coding method, which can exploit spatial correlation. The proposed method classifies wavelet coefficients into groups according to their parents´ magnitude. Each group is chosen in order of the magnitude and scanned to keep spatial correlation. It outperforms the zerotree-based coding approach especially at low bit rate