Robotics audition using Kinect

Robot audition systems are expected to support a variety of civilian and rescue applications in hazardous situations. Sensed data can only be interpreted meaningfully when referenced to the location of the sensor, making localization an important area of research. In this paper, we have developed sound source localization system for our Fire Bird VI robot. Localization algorithms like cross correlation (CC), phase transform (PHAT) and maximum-likelihood (ML) are explored to find the direction of arrival (DOA) by estimating the time delay of arrival (TDOA) from the received signals of linear array microphones of Kinect sensor. The sound signals comprising of different sample pings and pause durations ranging from 3 ms to 3 s durations, frequencies varying from 100 Hz to 5 kHz are tested using different microphone pairs of Kinect in different azimuths (DOA) ranging from 0° to 180° across different distances like 1 m, 1.5 m and 2 m. The performance of localization algorithms is evaluated by computing the error between estimated DOA and actual DOA. It is found that PHAT algorithm outperformed others, however some errors are obtained due to inherent reverberation affects may have caused by room. The authors also present practical limitations which result in errors for different azimuths based on distance between microphone pairs and sampling frequency of signals.