A methodology for sound source localization and tracking: Development of 3D microphone array for near-field and far-field applications

Acoustic source localization and tracking using microphone arrays has become a focus of interest in room acoustics, teleconference systems and tracking of sound producing objects. The current methods to estimate the source localization depend on conventional time-delay estimation techniques between microphone pairs, however, ignoring the ambient noise, reflections from surrounding and reverberation in the closed space. In this study, an acoustic source localizer and tracker (ASLT) based on 3D microphone array is designed and developed for real time source detection and localization. Two practical approaches were examined and evaluated, based on direction of arrival (DOA) estimation techniques and steered power response (SPR) of array algorithms in order to improve the accuracy for tracking multiple sources in full 3D coordinates. Among time delay estimation techniques, generalized cross correlation (GCC) is employed in frequency domain using multiple combinations of microphone pairs of the array with Phase transform (PHAT) weighting function for optimum detection of sources in the presence of reverberant environments. PHAT gives a good performance in the presence of ambience, even when the signal to noise ratio (SNR) is low. For SPR, minimum variance distortion less response (MVDR) beamformer weights are evaluated and purposed for accurate source tracking applications. A microphone array is designed using six transducers in spherical configurations and used for the evaluated for proposed methodology. The measurements are carried out in a reverberant chamber under different noise conditions to validate the practicality of the algorithmic chain and finally, the results are obtained and presented to demonstrate the efficiency of the proposed microphone array design and localization technique.