Histogram equalization to model adaptation for robust speech recognition

  • Authors:
  • Youngjoo Suh;Hoirin Kim

  • Affiliations:
  • Korea Advanced Institute of Science and Technology, Daejeon, South Korea;Korea Advanced Institute of Science and Technology, Daejeon, South Korea

  • Venue:
  • EURASIP Journal on Advances in Signal Processing
  • Year:
  • 2010

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Abstract

We propose a new model adaptation method based on the histogram equalization technique for providing robustness in noisy environments. The trained acoustic mean models of a speech recognizer are adapted into environmentally matched conditions by using the histogram equalization algorithm on a single utterance basis. For more robust speech recognition in the heavily noisy conditions, trained acoustic covariance models are efficiently adapted by the signal-to-noise ratio-dependent linear interpolation between trained covariance models and utterance-level sample covariance models. Speech recognition experiments on both the digit-based Aurora2 task and the large vocabulary-based task showed that the proposed model adaptation approach provides significant performance improvements compared to the baseline speech recognizer trained on the clean speech data.