A directional noise suppressor with an adjustable constant beamwidth for multichannel signal enhancement

This paper proposes a directional noise suppressor with an adjustable constant beamwidth for multichannel signal enhancement. A directional gain based on inter-channel phase difference is combined with a spectral gain commonly used in noise suppressors (NS). The beamwidth can be specified as passband edges of the directional gain. In order to implement frequency-independent constant beamwidth, frequency-proportionate band-edge phase differences are determined for the passband. Stereo perception is preserved by weighting stereo input with the common directional and spectral gain. Evaluation with signals recorded by a commercial PC demonstrates that the signal-to-noise ratio improvement and the PESQ score for the enhanced signal are equally improved in two channels by 26.1 dB and 0.2 over a conventional NS. ILD difference between the input and the output is small when the target-signal dominates the input signal.