Kong, Ying-YeeMullangi, AlaKokkinakis, Kostas2014-05-012014-05-012014-04-18Kong Y-Y, Mullangi A, Kokkinakis K (2014) Classification of Fricative Consonants for Speech Enhancement in Hearing Devices. PLoS ONE 9(4): e95001. http://dx.doi.org/10.1371/journal.pone.0095001https://hdl.handle.net/1808/13614Objective To investigate a set of acoustic features and classification methods for the classification of three groups of fricative consonants differing in place of articulation. Method A support vector machine (SVM) algorithm was used to classify the fricatives extracted from the TIMIT database in quiet and also in speech babble noise at various signal-to-noise ratios (SNRs). Spectral features including four spectral moments, peak, slope, Mel-frequency cepstral coefficients (MFCC), Gammatone filters outputs, and magnitudes of fast Fourier Transform (FFT) spectrum were used for the classification. The analysis frame was restricted to only 8 msec. In addition, commonly-used linear and nonlinear principal component analysis dimensionality reduction techniques that project a high-dimensional feature vector onto a lower dimensional space were examined. Results With 13 MFCC coefficients, 14 or 24 Gammatone filter outputs, classification performance was greater than or equal to 85% in quiet and at +10 dB SNR. Using 14 Gammatone filter outputs above 1 kHz, classification accuracy remained high (greater than 80%) for a wide range of SNRs from +20 to +5 dB SNR. Conclusions High levels of classification accuracy for fricative consonants in quiet and in noise could be achieved using only spectral features extracted from a short time window. Results of this work have a direct impact on the development of speech enhancement algorithms for hearing devices.This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.http://creativecommons.org/licenses/by/4.0/Article10.1371/journal.pone.0095001openAccess