This paper proposes an adaptive threshold estimation method for image denoising in the wavelet domain based on the generalized Guassian distribution(GGD) modeling of subband coefficients. The proposed method called NormalShrink is computationally more efficient and adaptive because the parameters required for estimating the threshold depend on subband data .The threshold is computed by βσ 2 / ...

In this paper, we introduce a polyphase implementation and design of an oversampled K-channel generalized DFT (GDFT) l-ter bank, which can be employed for subband adaptive ltering, and therefore is required to have a low aliasing level in the subband signals. A polyphase structure is derived which can be factorized into a real valued polyphase network and a GDFT modulation. For the latter, an F...

NON-UNIFORM SUBBAND ADAPTIVE FILTERS Jacob D. Griesbach, Michael Lightner, and Delores M. Etter Department of Electrical and Computer Engineering University of Colorado Boulder, CO 80309 [email protected], [email protected], [email protected] ABSTRACT Minimum mean square error estimators have been developed for non-uniform subband adaptive filters (SAFs) in system modeling configuratio...

A new adaptive speech enhancement system, which utilizes a second-generation wavelet transform (SGWT) decomposition and a novel adaptive subband thresholding technique, is presented. The adaptive thresholding technique is based on accurate estimation of subband segmental signal-to-noise ratio (SegSNR) and voiced/unvoiced classification of the speech. First, the speech signal is segmented and ea...

This paper concerns the filter design problem for a recent proposed polyphase filter bank with arbitrary number of subband channels. According to the perfect reconstruction condition for I-D case presented in [ I ] , an analytical formula for the filter design is developed. Compared with direct numerical design algorithms. this analytical formula allows one to design the required low-pass FIR p...

Abstract The optimization of subband filter banks for signal and image coding is normally dealt with by numerical means. It will be shown that this optimization can be done analytically in the case of the 4-tap CQF prototype filter. Coding gain and aliasing energy were considered in the optimization. Using parametrizations of the prototype filter coefficients it was found that the optimal filte...

In this paper, a novel audio coding algorithm is proposed where the warped linear prediction (WLP) technique is employed to construct a perceptual preand post-filter for subband audio coding. A modified signal-to-mask ratio (SMR) calculation is given for subband coding of the WLP residuals of audio signals. The concept of perceptual entropy (PE) is extended to subband coding, resulting in the s...

In this paper, the literature published on lossy compression of seismic data using the popular subband coding technique is reviewed. The strong links between subband coding, transform coding, and the more recent discrete wavelet transform coding are described. The performance of seismic data subband coding depends on the proper choice of lter bank and frequency partitioning in the subband domai...