Objective Quality Evaluation Method for Noise-Reduced Speech

Noritsugu EGI  Hitoshi AOKI  Akira TAKAHASHI  

IEICE TRANSACTIONS on Communications   Vol.E91-B   No.5   pp.1279-1286
Publication Date: 2008/05/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e91-b.5.1279
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Communication Quality)
Category: Subjective and Objective Assessments of Audio and Video Media Quality
objective quality,  subjective quality,  noise reduction,  listening test,  speech,  

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We present a method for the objective quality evaluation of noise-reduced speech in wideband speech communication services, which utilize speech with a wider bandwidth (e.g., 7 kHz) than the usual telephone bandwidth. Experiments indicate that the amount of residual noise and the distortion of speech and noise, which are quality factors, influence the perceived quality degradation of noise-reduced speech. From the results, we observe the principal relationships between these quality factors and perceived speech quality. On the basis of these relationships, we propose a method that quantifies each quality factor in noise-reduced speech by analyzing signals that can be measured and assesses the overall perceived quality of noise-reduced speech using values of these quality factors. To verify the validity of the method, we perform a subjective listening test and compare subjective quality of noise-reduced speech with its estimation. In the test, we use various types of background noise and noise-reduction algorithms. The verification results indicate that the correlation between subjective quality and its objective estimation is sufficiently high regardless of the type of background noise and noise-reduction algorithm.