Wavelet packet algorithm for quadtree-based embedded image coding
Wavelet packets represent an elegant generalization of the wavelet transform, capable of providing arbitrary frequency resolution to meet a signal's spectral behaviors. Recent research advances have shown that wavelet-based image compression techniques offer several advantages over traditional techniques in terms of progressive transmission capability and compression efficiency. The embedded compression techniques - tree-structured coding techniques, such as embedded zerotree wavelet (EZW) and set partitioning in hierarchical trees (SPIRT), and quadtree-structured coding techniques, such as wavelet quadtree (WQT), multigrid embedded (MGE) and EZW based on intraband partitioning (EZW-IP), - demonstrate the competitive performance of wavelet based compression schemes. This paper describes the wavelet packet algorithm which makes it suited to subsequent quad tree-based embedded image coders, such as EZW-IP. In our technique, the hierarchical sums of maximum magnitude of each quadtree node role as the decomposition criterion. The simulation results for various images show that the proposed algorithm gives a better coding efficiency than the octave-band decomposition.