Simultaneous Declipping and Beamforming via Alternating Direction Method of Multipliers

Audio declipping aims to reconstruct the original signal from a clipped observed signal. Clipping has a negative effect on subsequent multichannel processing such as beamforming. This is because the channel-wise nonlinear distortion deteriorates the spatial covariance matrix in the time-frequency domain. Hence, it is important to consider multichannel audio declipping that explicitly takes into account the subsequent audio signal processing. However, most of the existing methods have been developed for the single-channel case. In this paper, we propose a joint optimization method for declipping and beamforming. The multichannel declipped signal and the spatial filter are jointly optimized to sparsify the output of beamforming. Our experimental results show the effectiveness of the proposed method compared to the beamforming with prior declipping.