Tackling the Combined Effects of Reverberation and Masking Noise Using Ideal Channel Selection PurposeIn this article, a new signal-processing algorithm is proposed and evaluated for the suppression of the combined effects of reverberation and noise.MethodThe proposed algorithm decomposes, on a short-term basis (every 20 ms), the reverberant stimuli into a number of channels and retains only a subset of the channels satisfying a ... Article
Article  |   April 01, 2012
Tackling the Combined Effects of Reverberation and Masking Noise Using Ideal Channel Selection
 
Author Affiliations & Notes
  • Oldooz Hazrati
    The University of Texas at Dallas, Richardson
  • Philipos C. Loizou
    The University of Texas at Dallas, Richardson
  • Correspondence to Philipos C. Loizou: loizou@utdallas.edu
  • Editor: Sid Bacon
    Editor: Sid Bacon×
  • Associate Editor: Eric Healy
    Associate Editor: Eric Healy×
Article Information
Hearing & Speech Perception / Acoustics / Speech, Voice & Prosody / Hearing
Article   |   April 01, 2012
Tackling the Combined Effects of Reverberation and Masking Noise Using Ideal Channel Selection
Journal of Speech, Language, and Hearing Research, April 2012, Vol. 55, 500-510. doi:10.1044/1092-4388(2011/11-0073)
History: Received March 25, 2011 , Accepted August 15, 2011
 
Journal of Speech, Language, and Hearing Research, April 2012, Vol. 55, 500-510. doi:10.1044/1092-4388(2011/11-0073)
History: Received March 25, 2011; Accepted August 15, 2011
Web of Science® Times Cited: 10

PurposeIn this article, a new signal-processing algorithm is proposed and evaluated for the suppression of the combined effects of reverberation and noise.

MethodThe proposed algorithm decomposes, on a short-term basis (every 20 ms), the reverberant stimuli into a number of channels and retains only a subset of the channels satisfying a signal-to-reverberant ratio (SRR) criterion. The construction of this criterion assumes access to a priori knowledge of the target (anechoic) signal, and the aim of this study was to assess the full potential of the proposed channel-selection algorithm, assuming that this criterion could be estimated accurately. Listening tests with normal-hearing listeners were conducted to assess the performance of the proposed algorithm in highly reverberant conditions (T60 = 1.0 s), which included additive noise at 0 and 5 dB signal-to-noise ratios (SNRs).

ResultsA substantial gain in intelligibility was obtained in both reverberant and combined reverberant and noise conditions. The mean intelligibility scores improved by 44 and 33 percentage points at 0 and 5 dB SNR reverberation + noise conditions. Feature analysis of the consonant confusion matrices revealed that the transmission of voicing information was most negatively affected, followed by manner and place of articulation.

ConclusionsThe proposed algorithm produced substantial gains in intelligibility, and this benefit was attributed to the ability of the proposed SRR criterion to detect accurately voiced or unvoiced boundaries. It was postulated that detection of those boundaries is critical for better perception of voicing information and manner of articulation.

Acknowledgment
This work was supported by National Institute of Deafness and Other Communication Disorders Grant R01 DC 010494, awarded to the second author.
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