Sound direction estimation using artificial ear

We propose a novel design of artificial robot ear and sound direction estimation method using the measured two output signals only. The spectral features in head-related transfer functions and in interaural transfer functions are distinctive across voice frequency band. Thus, these features provide effective sound cues to estimate sound direction using the measured two output signals. Bilateral asymmetry of microphone positions can enhance the estimation performance even in the median plane where interaural differences are vanished. Sound direction is estimated from interaural time difference and correlation between the log magnitudes of interaural transfer functions. The feasibility and the estimation performance of the designed artificial ear and the estimation method are verified in a real environment. In the experiment, we confirm that robots with the proposed artificial ear can find the direction of user from two output signals only with reasonable accuracy.