| Summary: | 碩士 === 國立交通大學 === 電機與控制工程系所 === 97 === The purpose of this thesis is to construct an audio surveillance system to recognize the interference sources and sound sources in a low signal-noise ratio (SNR) noisy environment. Traditionally, single microphone can not recognize the noise and sound sources in a low signal-noise ratio (SNR). First, the time delay between microphones are estimated from the multiple-channel sound data acquired by the digital microphone array acquisition system. Second, we suppress the effect of the interference sources by spatial filter to promote signal-noise ratio (SNR) and to reduce the false detection ratio. Second, we create the background model of surveillance system by using the signal characteristic and the Gaussian Mixture Modeling method, and then to estimate the model parameters by utilizing the EM algorithm. Finally, we can recognize the sound sources from the interference sources through the statistic information of sound field characteristic. A microphone array of 8 microphones with USB 1.1 interface was made for the implementation platform.
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