SOUND SOURCE LOCALIZATION IN THREE-DIMENSIONAL SPACE IN REAL TIME WITH REDUNDANCY CHECKS

Abstract

Triangulation is commonly used for source localization and most triangulation applications are based on intersection of the bearing direction to locate a source on a two-dimensional plane. In this paper, two new mathematical models (a basic model and an improved one) that expands the traditional triangulation concept to three-dimensional space are developed to locate multiple incoherent sound sources. The basic model uses four microphones and concentrates on solving a set of three quadratic equations simultaneously. The improved model requires more than four microphones and uses the solution from the basic model, as well as analyzing the intersection of bearing angles. Redundancy checks on the time differences of arrival are added to further reduce the source localization error in the improved model. Moreover, the input data are pre-processed and de-noised through filtering and windowing to enhance the effective signal to noise ratio. Various sound sources are tested, including transient, impulsive, continuous, broad-band, and narrow-band sounds. Numerical simulations and experimental validation using the real world sound sources are conducted. The impacts of the source direction/source detection range on the accuracy of source localization results are examined and discussed.