Spectrum flipping for wavelet packet decomposition
Jianyu Lin · 2007
Abstract – In this paper, it is shown that the higher compression performance of biorthogonal wavelet filters over orthogonal wavelet filters is the combined effect from (1) the asymmetry of the frequency responses of the biorthogonal wavelet filters and (2) the non-flat spectra of the signals to be decomposed. Based upon this observation, an improved wavelet packet decomposition method for natural images through swapping the analysis and synthesis filters is proposed. The method leads to consistent improved compression performance at a very wide range of data rates without increasing computational complexity. Key words – Compression performance of wavelets, Frequency responses of biorthogonal wavelet filters, Wavelet packet decomposition 1