We propose three new adaptive noise suppression algorithms for enhancing noise-corrupted speech: smoothed spectral subtraction (SSS), vector quantization of line spectral frequencies (VQ-LSF), and modiied Wiener ltering (MWF). SSS is an improved version of the well-known spectral subtraction algorithm, while the other two methods are based on generalized Wiener ltering. We have compared these t...

In this paper we investigate an alternative approach to the design of low-bit rate (LBR) quantisation. This approach incorporates phonetic information into the structure of Line Spectral Frequency (LSF) codebooks. In prior work vector quantisation (VQ) has been used to quantise stochastic processes. Speech signals can, however, be described in terms of phonetic segments and linguistic rules. A ...

Source coding based on Gaussian Mixture Models (GMM) has been recently proposed for LPC quantization. We address in this paper the related problem of designing efficient codebooks for Gaussian vector sources. A new technique of ellipsoidal lattice vector quantization (VQ) is described, based on 1) scalar companding optimized for Gaussian random variables and 2) rectangular lattice codebooks wit...

We propose a new method for estimating Line Spectral Frequency (LSF) trajectories that uses unscented Kalman filtering (UKF). This method is based upon an iterative Expectation Maximisation (EM) approach in which LSF estimates are generated during a forward pass and then smoothed during a backward pass. The EM approach also provides re-estimated Kalman filter parameters for further forward-back...

In this paper, the use of Karhunen-Loeve transform (KLT) and discrete cosine transform (DCT) is studied for encoding of the line spectrum frequency (LSF) parameters at variable bit rate (VBR). For VBR coding, scalar quantization (SQ) is used with Huffman coding. The basic idea in developing these schemes is using linear transform to exploit the strong intraframe and interframe correlation of LS...

Despite an overall consensus that Autism Spectrum Disorder (ASD) entails atypical processing of human faces and emotional expressions, the role of neural structures involved in early facial processing remains unresolved. An influential model for the neurotypical brain suggests that face processing in the fusiform gyrus and the amygdala is based on both high-spatial frequency (HSF) information c...

Iwata M, Silva Enciso J, Greenberg BH. Selective and specific regulation of ectodomain shedding of angiotensin-converting enzyme 2 by tumor necrosis factor -converting enzyme. Am J Physiol Cell Physiol 297: C1318–C1329, 2009. First published September 16, 2009; doi:10.1152/ajpcell.00036.2009.—Angiotensin-converting enzyme 2 (ACE2) is a newly identified regulator of the renin-angiotensin system....

Recent models of visual recognition have suggested that perceptual analysis may start with a parallel extraction of different spatial frequencies (SF), using a preferential coarse-to-fine (low-to-high SF) sequence of processing. A rapid extraction of low spatial frequency (LSF) information may thus provide an initial and crude parsing of the visual scene, subsequently refined by slow but more d...

In the context of vector quantization (VQ) of the line spectrum frequency (LSF) parameters, we determine experimentally a spectral distribution of quantization error perceived to be " balanced " , i.e., error at all frequencies contributing equally, on average, to the perceived distortion. Quantizers which have a balanced distribution should outperform those which don't, given the same number o...