2D sound source localization on a mobile robot with a concentric microphone array

The purpose of this paper is to report the devised arrangement of a microphone array suitable for a mobile robot and to develop a robotic audition system to recognize the environment. The paper first describes the sum and delay beam forming (SDBF) algorithm and its common problem: side lobes. The array we developed shows smaller side lobes when beam forming. It provides high quality localization and separation for multiple sound sources. Then we achieved a sound sources mapping system by using a wheeled robot equipped with the microphone array. The robot localizes sound direction on the run and estimates sound positions using triangulation. Accumulation of data results in high accuracy. The system can estimate 3 different pressure sounds with a 200 mm position error. Moreover, the high quality sound source separation has proved useful in improving speech recognition.