Locating sound source in the presence of reflections

Pao Yue-kong Library Electronic Theses Database

Locating sound source in the presence of reflections

 

Author: Shi, Fangdi
Title: Locating sound source in the presence of reflections
Degree: M.Eng.
Year: 2014
Subject: Acoustic localization.
Directional hearing.
Hong Kong Polytechnic University -- Dissertations
Department: Dept. of Building Services Engineering
Pages: x, 71 leaves : illustrations (some color) ; 30 cm
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b2760618
URI: http://theses.lib.polyu.edu.hk/handle/200/7640
Abstract: Sound source located has significant meaning and is widely used in many fields nowadays, however, when strong reflections exist, the environment of measurement is complex, which will influence the accuracy a lot. The methodologies on locating source may be categorized into two groups: one is to measure the time of arrival between a transmitted pulse and its echo and another is to estimate the time difference of arrival (TDOA) between two sensors mounted at different points in space. In this dissertation, the beamforming theory and TDOA theory will be reviewed. And this dissertation also intends to develop a methodology based on beamforming algorithm that allows one to locate sound source and distinguish the image of the source from the real source in three-dimensional space in real time. Input data are preprocessed by denoising, windowing, filtering, and averaging to enhance the accuracy. The results are then post-processed using triangulations, autonomous error estimations and corrections. To acquire a better understanding of this approach, numerical simulations are disposed first to examine the influence of various parameters such as signal noise ratio, frequency on the accuracy, and microphone spacing and source distances and spatial resolution of the prediction. Experiments are performed in different environments to evaluate its effectiveness in locating sources, including white noise signal and impulse signal. In particular, three kinds of material are chosen to provide reflections, which help to analyze the performance of the system.

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