Nested Generalized Sidelobe Canceller for Joint Dereverberation and Noise Reduction
Abstract: Speech signal is often contaminated by both room reverberation and ambient noise. A nested generalized sidelobe canceller (GSC) beamforming structure is proposed, comprising an inner and outer GSC beamformers (BFs), that decouples the speech dereverberation and the noise reduction operations. The BF is implemented in the short-time Fourier transform (STFT) domain. Two alternative reverberation models are adopted. In the first, used in the inner GSC, reverberation is assumed to comprise a coherent, early, component and a diffused late component. In the second, used in the outer GSC, the influence of the entire acoustic transfer function (ATF) is modeled as a convolution along the frame index in each frequency. Unlike other BF designs that must be updated in each time-frame, the proposed structure is time-invariant in static scenarios. Experiments with both simulated and recorded environments verify the effectiveness of the proposed structure in comparison to other competing algorithms.