Optimized gain functions in ideal time-frequency masks and their application to dereverberation for cochlear implants

Abstract

The present study investigated three different reverberation suppression rules based on the parametric ideal ratio mask, which is a generalization of the classical Wiener filter with additional parameters controlling the threshold and slope. Automatic selection of parameter values for the ideal ratio mask was performed using particle swarm optimization. Three different parameter sets were tested using sentences corrupted by reverberation. The results demonstrated that when optimizing parameters based on an objective measure of speech quality rather than intelligibility, cochlear implant users were able to perform at a level equivalent to that attainable with anechoic stimuli.