Spherical microphone array post-filtering for reverberation suppression using isotropic beamformings

摘要

Dereverberation or reverberation suppression techniques are important for many applications. Beamforming is an effective technique for speech enhancement; however, it is impossible to suppress the reverberation arriving from the target direction for beamforming. The non-linear post-filtering methods have been proposed for reverberation suppression based on Wiener filtering. Post-filtering can suppress the reverberation from the output of beamforming when the power spectral density (PSD) of the desired reverberation is estimated. In this paper, we assume that reverberation arrives isotropically. Under this assumption, using isotropic beamforming on the spherical harmonic (SH) domain, the PSD of reverberation can be estimated. Based on our experiments, the proposed method is an effective tool for suppressing reverberation; furthermore, it can be used to reduce background noise.