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  • Research Article
  • Open Access

Efficient Alternatives to the Ephraim and Malah Suppression Rule for Audio Signal Enhancement

EURASIP Journal on Advances in Signal Processing20032003:910167

  • Received: 31 May 2002
  • Published:


Audio signal enhancement often involves the application of a time-varying filter, or suppression rule, to the frequency-domain transform of a corrupted signal. Here we address suppression rules derived under a Gaussian model and interpret them as spectral estimators in a Bayesian statistical framework. With regard to the optimal spectral amplitude estimator of Ephraim and Malah, we show that under the same modelling assumptions, alternative methods of Bayesian estimation lead to much simpler suppression rules exhibiting similarly effective behaviour. We derive three of such rules and demonstrate that, in addition to permitting a more straightforward implementation, they yield a more intuitive interpretation of the Ephraim and Malah solution.


  • noise reduction
  • speech enhancement
  • Bayesian estimation

Authors’ Affiliations

Signal Processing Group, Department of Engineering, University of Cambridge, Cambridge, CB2 1PZ, UK


© Copyright © 2003 Hindawi Publishing Corporation 2003