Wavelet packet based on the top-down method

The wavelet packet based on top-down method is proposed. Previously, Ramchandran and Vetterli have proposed a single tree algorithm, however, it requires of a relatively longer execution time. In comparison to the single tree algorithm, our proposed technique reduces the packet computation time by adopting top-down packet tree architecture in which the variance of the band roles as the decomposition and bit allocation criterion. The bits are allocated to each band by the target bit-rate and variance. Coding is performed for each band within the bit allocation. The simulation results using various still images show that the proposed algorithm requires of a less execution time in comparison to that of the conventional single tree algorithm at the minimal cost of the reduced PSNR. Applications of our proposed method in which time factor is crucial should be useful.