Multichannel dereverberation for hearing aids with interaural coherence preservation

Dereverberation for multichannel hearing aids is still a field of extensive research. If a single desired source is assumed, many binaural spatial filtering techniques such as the minimum variance distortionless response beamformer or the rank-one multichannel Wiener filter (MWF) distort the binaural cues of the residual undesired signal components. A recently proposed spatial filter minimizes the mean squared error plus an additional cost function to preserve the longterm interaural coherence of a diffuse noise field between the hearing aid signals. In this paper, we adapt this approach to binaural dereverberation by modeling the reverberation as a time-varying diffuse sound field. Using this approach, a considerable amount of reverberation and noise reduction can be achieved. Experimental results show that we can preserve the coherence at the output without significantly impairing the reverberation and noise reduction performance.