TDE-ILD-based 2D half plane real time high accuracy sound source localization using only two microphones and source counting

Abstract

The sound source localization methods, in general, can be divided into DOA, TDOA (ITD or TDE) and ILD based methods. DOA based methods need many microphones for high accuracy narrowband sound source localization. Also ILD based methods need high accuracy level measurement hardware and need one source to be enough dominant. In outdoor cases, TDOA based methods with lower accuracy than DOA based methods but fewer microphones and less computation time, are used for 2D wideband sound source localization using only three microphones. Using these methods, outdoor (far distance) high accuracy sound source localization in different climates needs highly sensitive and high performance microphones which are very expensive. In the last decade, some papers were published to reduce the microphones count in indoor 2D sound source localization using TDE and ILD based methods simultaneously. However, these papers do not mention that using ILD based methods need only one dominant source to be active for high resolution localizing. In this paper we try to apply this method in outdoor (low degree reverberation) cases for a dominant sound source and evaluate it regarding different noise powers and source distances. Based on the evaluation of this method, a special and simple microphones arrangement is implemented and source counting method is used to find that only one dominant sound source is active in the localization area. Experimental results show that this method is useful in outdoor and low degree reverberation cases when we try to raise SNR using spectral subtraction and source counting methods.