A two-stage speech activity detection system considering fractal aspects of prosody

  • Authors:
  • Soheil Shafiee;Farshad Almasganj;Bahram Vazirnezhad;Ayyoob Jafari

  • Affiliations:
  • Biomedical Engineering Department, Amirkabir University of Technology (Polytechnic of Tehran), Iran;Biomedical Engineering Department, Amirkabir University of Technology (Polytechnic of Tehran), Iran;Biomedical Engineering Department, Amirkabir University of Technology (Polytechnic of Tehran), Iran and Iran Electronics Research Institute, Iran;Biomedical Engineering Department, Amirkabir University of Technology (Polytechnic of Tehran), Iran

  • Venue:
  • Pattern Recognition Letters
  • Year:
  • 2010

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Abstract

Speech Activity Detectors (SADs) are essential in the noisy environments to provide an acceptable performance in the speech applications, such as speech recognition tasks. In this paper, a two-stage speech activity detection system is presented which at first takes advantage of a voice activity detector to discard pause segments out of the audio signals; this is done even in presence of stationary background noises. In the second stage, the remained segments are classified into speech or non-speech. To find the best feature set in speech/non-speech classification, a large set of robust features are introduced; the optimal subset of these features are chosen by applying a Genetic Algorithm (GA) to the initial feature set. It has been discovered that fractal dimensions of numeric series of prosodic features are the most speech/non-speech differentiating features. Models of the system are trained over a Farsi database, FARSDAT, however, test experiments on the TIMIT English database have been also conducted. Employing the SAD system in conjunction with an ASR system, has been resulted in a relative Word Error Rate (WER) reduction of as high as 28.3%.