Processing finite length signals via filter banks without border distortions: a non-expansionist solution

In this paper we introduce a novel and general matrix formulation of classical signal extension methods for subband processing of finite length signals. Considering a paraunitary 2-channel filter bank as transformation cell, this new characterization makes it possible to show that perfect reconstruction of finite signals can be ensured without resorting to extra subband samples; thus, by using some traditional signal extension methods, non-expansionist transforms can be defined. Some of these transformations are analyzed to illustrate our theoretical results.