Adaptive wavelet for speech coding

This paper presents a comparative study of adaptive wavelet design for a speech coder based on wavelet-type multiresolution transforms. It is concerned with the problem of choosing suitable transforms that are adapted to the given speech signal in the sense that they maximize the coding gain at each resolution level. Four adaptive algorithms are reviewed for solving this problem in the framework of lattice realization of multirate lossless filter banks. The resulting speech coding scheme will be presented. The performance is compared among each of the algorithms, as well as some non-adapted multiresolution transforms.