S. Voran

Abstract: Part 1 of this paper describes a new approach to the objective estimation of perceived speech quality. This new approach uses a simple but effective perceptual transformation and a distance measure that consists of a hierarchy of measuring normalizing blocks. Each measuring normalizing block integrates two perceptually transformed signals over some time or frequency interval to determine the average difference across that interval. This difference is then normalized out of one signal, and is further processed to generate one or more measurements. In Part II the resulting estimates of perceived speech quality are correlated with the results of nine subjective listening tests. Together, these tests include 219 4-kHz bandwidth speech codecs, transmission systems, and reference conditions, with bit rates ranging from 2.4 to 64 kb/s. When compared with six other estimators, significant improvements are seen in many cases, particularly at lower bit rates, and when bit errors or frame erasures are present. These hierarchical structures of measuring normalizing blocks, or other structures of measuring normalizing blocks may also address open issues in perceived audio quality estimation, layered speech or audio coding, automatic speech or speaker recognition, audio signal enhancement, and other areas.

Keywords: distance measures; perceived speech quality; bit errors; objective estimation; audio signal; frame erasures; highly compressed digital speech; human hearing process; measuring normalizing block technique; objective estimators; perceptual

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Institute for Telecommunication Sciences
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For technical information concerning this report, contact:

Stephen D. Voran
Institute for Telecommunication Sciences
(303) 497-3839

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