Tobias Rodemann, "Spectral cues to source position in robots with arbitrary ear shapes", Proceedings of ICAR 2011, 2011.

The ability to localize a sound source is very important in interaction scenarios where the robot has to face the speaker. It is known that the horizontal position of a sound source can be easily estimated using only two microphones, however, the elevation is more difficult to determine in such a configuration. To deal with these problems the use of special outer ears (so called pinnae) has been proposed in order to allow the use of spectral cues for elevation estimation. Here we compare two algorithms that can extract spectral cues for arbitrary ear shapes and are able to localize a broad class of sounds under challenging real-world conditions. The algorithms run in real-time and are implemented on a real robot-head.