Multiple statistical models for soft decision in noisy speech enhancement

  • Authors:

  • Joon-Hyuk Chang;Saeed Gazor;Nam Soo Kim;Sanjit K. Mitra

  • Affiliations:

  • School of Electronic Engineering, Inha University, Incheon 402-751, Korea;Department of Electrical and Computer Engineering, Queen's University, Kingston, Ont., Canada K7L 3N6;School of Electrical Engineering and INMC, Seoul National University, Seoul, Kwanak 151-742, P.O. Box 34, Korea;Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, USA

  • Venue:
  • Pattern Recognition
  • Year:
  • 2007

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Abstract

Most speech enhancement algorithms are based on the assumption that speech and noise are both Gaussian in the discrete cosine transform (DCT) domain. For further enhancement of noisy speech in the DCT domain, we consider multiple statistical distributions (i.e., Gaussian, Laplacian and Gamma) as a set of candidates to model the noise and speech. We first use the goodness-of-fit (GOF) test in order to measure how far the assumed model deviate from the actual distribution for each DCT component of noisy speech. Our evaluations illustrate that the best candidate is assigned to each frequency bin depending on the Signal-to-Noise-Ratio (SNR) and the Power Spectral Flatness Measure (PSFM). In particular, since the PSFM exhibits a strong relation with the best statistical fit we employ a simple recursive estimation of the PSFM in the model selection. The proposed speech enhancement algorithm employs a soft estimate of the speech absence probability (SAP) separately for each frequency bin according to the selected distribution. Both objective and subjective tests are performed for the evaluation of the proposed algorithms on a large speech database, for various SNR values and types of background noise. Our evaluations show that the proposed soft decision scheme based on multiple statistical modeling or the PSFM provides further speech quality enhancement compared with recent methods through a number of subjective and objective tests.