Sound Source Localization Using a Pinna-based Profile Fitting Method

In a two-microphone approach, interaural differences in time (ITD) and interaural differences in sound intensity (IID) have generally been used for sound source localization. But those cues are not effective for vertical localization in the median plane (direct front). For that purpose, spectral cues based on features of head-related transfer functions (HRTF) have been investigated, but they are not robust enough against signal variations and environmental noise. In this paper, we use a “profile” as a cue while using a combination of pinna specially designed for vertical localization. The observed sound is converted into a profile containing information about reflections as well as ITD and IID data. The observed profile is decomposed into signal and noise by using template profiles associated with sound source locations. The template minimizing the residual of the decomposition gives the estimated sound source location. Experiments show this method can correctly provide a rough estimate of the vertical location even in a noisy environment.