Estimation of sound source orientation using eigenspace of spatial correlation matrix

We propose a method for estimating the sound source orientation by using the reflection sounds. The sound source orientation is important spatial information for promoting communication using teleconference systems. We assume that the observed signals captured using several microphones in a reverberant room are used for estimating the sound source orientation. Since the power of each reflection sound depends on the sound source orientation, the transfer functions between a sound source and multiple microphones are varied corresponding to the sound source orientation. We found that the eigenspace of spatial correlation constructed from the observed signals has a characteristic shape corresponding to the sound source orientation. We also proposed an efficient method for estimating the sound source orientation by matching the eigenspace of observed signals with pre-learned eigenspace models for every sound source orientation. In numerical experiments, we obtained about 80% accuracy. We confirmed the effectiveness of the proposed method.