Detection of user´s body movement for binaural hearing aids to control of directivity

Estimation of sound source directions and separation of the sound sources are implemented on many products widely, and one of the applications is binaural hearing aids. In conversation using binaural hearing aids, continuous tracking of sound sources with acoustics signals are sometimes complicated because sound sources move dynamically. In order to make the tracking of sound sources simple, it is considered to be helpful to use non-verbal information in communication. Since user´s body movement, including a head, corresponds to speakers´ positions, it is possible to estimate communication zone where sound sources locate by the head direction. In this paper, a head movement in conversation, as non-verbal information in communication, is focused, and two zone detection methods are discussed. A rotational angle of head movement is estimated by both acceleration by an accelerometer and angular velocity by angular velocity sensor which is attached to left ear position. The classification of spatial communication zone is performed by two methods, the threshold method and the support vector machine (SVM). As the results, performance on estimation of the target direction by the threshold-based method was slightly better than that by the SVM-based method.