A compact multi-sensor headset for hands-free communication

The need for hands-free communication has led to an increased popularity in the use of headsets with mobile phones. Comfort and portability concerns have led to the desire for headsets with a small form factor. Unfortunately, this size constraint typically requires that the microphone be placed farther from the user´s mouth, making it highly susceptible to environmental noise. One long term goal of our work is to develop a headset that can achieve the sound capture performance of a close-talking microphone located at the user´s mouth, while maintaining the desired compact size. Toward this end, we have designed a headset consisting of three air microphones and a bone-conductive sensor. The speech enhancement is performed in two stages, a fixed beamformer followed by a single-channel adaptive post-filter. Unlike other techniques, the beamformer is calibrated in a purely data-driven manner. The bone sensor provides a robust speech activity detector for use in the post-filtering stage. We present preliminary experimental results using real data collected in multiple environments. The proposed approach results in significant improvements in both speech recognition accuracy and SNR.