A Noise-Reduction Method With Coherence Enhancement for Binaural Hearing Aids

Abstract

In this work, a variation of the multichannel Wiener filter (MWF) for noise reduction in binaural hearing aid applications is proposed. This method provides improved spatial preservation for acoustic scenarios comprised of one single-point target (speech) and one single-point interfering (noise) acoustic sources. It employs a regularization penalty term based on the inverse of the magnitude of the interaural coherence (IC), with the aim of enhancing the original azimuth perception of the interferent source. The proposed penalty term artificially intensifies the IC of the residual interference, increasing similarity in both ears. This is of special value for low-coherent reverberant acoustic signals, in which the reliability of the received binaural cues associated to the single-point interferent source was degraded by multiple acoustic reflections. Simulation results obtained with objective criteria show that, in addition of providing improved spatial preservation for the interferent source, the proposed approach may also provide higher noise reduction performance as compared to the conventional MWF approach. Further, it also yields an extended range for the target and interference spatial-preservation trade-off, as compared to a previously developed competing method. Psychoacoustic experiments with normal hearing volunteers corroborate theoretical and simulation findings.