Designs And Applications Of Three-band Biorthogonal Filterbanks Via Lifting

Recently, there have been growing interests in the theory and the design ofmultirate filter banks. It has been widely applied to communications, speech andimage processing, noise reduction as well as other fields. The subband coding gain(GSBC) expresses the ratio of its squared-error distortion to that of the pulse codemodulation (PCM) under a given bit-rate. It is an important index to evaluate afilter-banks' coding efficiency. In this paper, Firstly, the first method is studied for the design of three-channeladaptive biorthogonal filter banks via lifting. In the paper, we establish the parameterstructure of three-channel biorthogonal filter banks via lifting, and design a family ofthree-channel signal-adapted FIR biorthogonal filter banks. In design, the subbandcoding gains are taken as the objective functions to optimize. Starting from anarbitrary FIR orthogonal or biorthogonal filter bank, three pairs of lifting filters areoptimized in turn to improve subband coding gains. Experimental results show thatthe subband coding gains can be improved when an appropriate initial filter bank ischosen. Next, the method II is investigated. Unlike the method I, we utilize anotherthree-band lifting mode to establish the parameter structure. Under the structure, thesubband coding gain is still used as the objective function, the former four liftingfilters are firstly jointly optimized and then the residual two lifting filters areoptimized. The method can markedly improve the subband coding gains, andcomparing with the method I the subband coding gain obtains also someimprovement.