Simplified Localization of a Sound Source in 3-D Space Utilizing Microphone's Unidirectional Sensitivity Characteristics

Abstract

This paper proposes a simplified measurement principle of an audio sound source localization in a 3-D space. Such kind of differences like the transferring time, phase shift, and level of the sound wave are treated for the measurement in general. Our approach is to use the differences of sound levels by taking the advantage of the condenser microphone's unidirectional sensitivity characteristics so that the localization is performed by simple signal processing. Basically the sound levels are collected at two sensor towers which are separated with a certain distance. Each tower has four microphones located at tetrapod positions for monitoring the levels from all directions. We show the calculation procedure for extracting the location of the sound source. We made an experimental set and collected sound data for verifying the measurement principle. The results show that the directional and positional errors of the sound source are less than 0.22[rad] and 1.2[m] at the distance 5[m], for instance. Error analysis shows that these data are reasonable. Limitation of measurement accuracy improvement is also described.