A computational model for assessment of speech intelligibility in informational masking

The existing auditory computational models for evaluating speech intelligibility can only account for energetic masking, and the effect of informational masking is rarely described in these models. This study was aimed to make a computational model considering the mechanism of informational masking. Several psychoacoustic experiments were conducted to test the effect of informational masking on speech intelligibility by manipulating the number of masking talker, speech rate, and the similarity of F0 contour between target and masker. The results showed that the speech reception threshold for the target increased as the F0 contours of the masker became more similar to that of the target, suggesting that the difficulty in segregating the target harmonics from the masker harmonics may underlie the informational masking effect. Based on these studies, a new auditory computational model was made by inducing the auditory function of harmonic extraction to the traditional model of speech intelligibility index (SII), named as harmonic extraction (HF) model. The predictions of the HF model are highly consistent with the experimental results.