Assessment of Objective Quality Measures for Speech Intelligibility

This paper assesses 9 prominent objective quality measures for their potential in intelligibility estimation. Degradation considered include additive noises and those introduced by coding and enhancement schemes, totalling 78 types. This paper is believed to be the first to conduct an assessment on such a large combination of quality measures and degradations allowing side-byside analysis. Experimental results show that the sophisticated perceptual-based measures which are superior for quality estimation, do not necessarily correlate well with human intelligibility and, in fact, give poorer correlations when enhancement schemes are considered. Meanwhile, the weighted spectral slope (WSS) emerges to be the most promising approach among all measures considered, scoring the highest correlation in 5 out of the 6 test sets. Worth noting are the positive correlations obtained with WSS which range from 0.14 to 0.86, as opposed to those with PESQ from -0.58 to 0.74. Such findings put WSS, a relatively conventional measure, in a new light as a potential intelligibility assessor.