Designing optimal filer banks for subband coding applications has recently attracted considerable attention [1]-[5]. In particular, the authors have developed an adaptive algorithm based on stochastic gradient descent (SGD) that enables one to optimize two channel paraunitary filter banks in an on-line fashion [3]. The idea has also been extended to the case of tree-structured filter banks [4]....

In this paper, we extend structures and factorizations for paraunitary filter banks yielding linear phase filters [1] to the oversampled case. We derive minimal factorizations for a subset of these banks, and propose some design examples.

This paper considers the design of the WSS paraunitary filterbanks composed of a single complex allpass filter and gives a new class of real-valued orthonormal symmetric wavelet bases. First, the conditions that the complex allpass filter has to satisfy are derived from the symmetry and orthonormality conditions of wavelets, and its transfer function is given to satisfy these conditions. Second...

This correspondence discusses the design and factorization of FIR paraunitary filter banks where several analysis filters are given. A lattice factorization-based algorithm is presented that provides complete and minimal characterization for nonlinear-phase and balanced linear-phase systems. As a result, the design problem can be formulated as an unconstrained optimization of the lattice coeffi...

Paraunitary filter banks are important for several signal processing tasks, including coding, multichannel deconvolution and equalization, adaptive beamforming, and subspace processing. In this paper, we consider the task of adapting the impulse response of a multichannel paraunitary filter bank via gradient ascent or descent on a chosen cost function. Our methods are spatio-temporal generaliza...

In this paper, we present a new structure for linear−phase filter banks without redundancy, which have unequal−length filters at each subband. First, we extend the simplified lattice structure of the linear−phase filter bank to the unequal−length linear−phase paraunitary filter bank. In general, the unequal−length linear−phase paraunitary filter bank has equal−length filters at both the analysi...

This paper addresses the problem of obtaining an explicit expression of all real FIR paraunitary filters. In this work, we present a general parameterization of 2-channel FIR orthogonal filters. Unlike other approaches which make use of a lattice structure, we show that our technique designs any orthogonal filter directly, with no need of iteration procedures. Moreover, in order to design an L-...

This paper derives two spatio–temporal extensions of the well-known FastICA algorithm of Hyvärinen and Oja that are applicable to the convolutive blind source separation task. Our time–domain algorithms combine multichannel spatio–temporal prewhitening via multistage least-squares linear prediction with novel adaptive procedures that impose paraunitary constraints on the multichannel separation...