Direction-Guided Spatial Attention for Multichannel Speech Enhancement

The direction of target speech is a crucial clue for multichannel speech enhancement. But its real-time estimation is usually very challenging, especially when the source is moving and in far-field reverb environments. Instead of directly estimating the direction, we propose a direction-guided spatial attention to automatically focus on the target source and incorporate it into masking neural beamformers for speech enhancement. Neural beamformers are trained to learn to preserve signals from the look direction areas and suppress signals from other direction areas as much as possible. Spatial attention is guided by an extra classification objective of the target direction to focus on the target direction area and select an appropriate neural beamformer to listen to the direction area of target speech. Systematic experiments demonstrate that the proposed approach improves the performances of both speech enhancement and far-field speech recognition against prior methods.