Feasibility of Estimating Direction of Arrival Based on Monaural Modulation Spectrum

This paper reports the feasibility of estimating the direction of arrival (DOA) using the monaural modulation spectrum (MMS). We investigated monaural cues for DOA estimation by analyzing the MMS of an observed signal in either ear on the basis of the head-related modulation transfer function (HRMTF). As a result, in the DOA estimation for azimuth variations, we found that MMS shapes were approximately drawn as arcs with azimuth variations in the same direction of the ear side. In articular, the effects of diffraction can be observed with azimuth variations in the opposite direction of the ear side. In the DOA estimation for elevation variations, we found that fluctuations of the MMS tend to be reduced as elevation varies from the top to the back of the head. In addition, these fluctuations tended to increase as elevation varied from the same side to the opposite side of the ear. Furthermore, we considered the feasibility of the horizontal DOA estimation method based on the basis of MMS and concluded that it could estimate DOA.