空間濾波器於麥克風陣列之設計

Beamforming Design of Microphone array

王基鴻(Ji-hong Wang)

指導教授 ： 徐國鎧

國立中央大學/資訊電機學院/電機工程學系/碩士(2012年)

摘要

本論文使用空間濾波器來處理麥克風之均勻線性陣列與均勻圓形陣列的訊號處理，應用線性限制最小變異（LCMV）演算法，目的為增強目標方向訊號並壓抑非目標方向訊號，並藉由估測聲源到各顆麥克風之間的傳遞衰減係數，調整麥克風電路的放大倍率，以降低麥克風之間的差異性。接著利用麥克風陣列訊號的空間資訊做聲源到達方向（DOA）估測，得到空間濾波器輸入端對於聲源方向的相對延遲時間（TDOA）。最後設計麥克風陣列類比放大電路接收聲音訊號，以驗證空間濾波器系統，並探求均勻線性陣列與均勻圓形陣列之異同。

關鍵字

空間濾波器 ； 線性最小變異限制 ； 麥克風陣列 ； 相對延遲時間 ； 傳遞衰減係數 ； 到達方向

並列摘要

This thesis investigates the signal processing of a microphone array when the arrangement of the microphones is a uniform linear array (ULA) or a uniform circular array (UCA), designing an implementation of a microphone-array beamforming. In real world environment, the speech signal received by a set of microphones contains the desired signal, interference, and ambient noise. In order to enhance the desired signal and reduce other signal, the algorithm, linearly constrained minimum variance (LCMV), is used. By estimating the channel attenuation factor between the source signal and each microphone, one can adjust the gain of the circuit to decline the difference between microphones. After that, the estimate of direction of arrival (DOA) from the spatial information of the microphone-array signal, the time difference of arrival (TDOA) between microphones due to the direction of source is obtained. Finally, by designing a microphone-array circuit to receive the voice signal, this study verifies the beamforming system in a noisy speech environment, and then discusses the difference between the signals received by a set of ULA and UCA.

並列關鍵字

linear constrained minimum variance (LCMV) ； microphone array ； channel attenuation factor ； direction of arrival (DOA) ； time difference of arrival (TDOA)

參考文獻

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[3] B. D. Van Veen and K. M. Buckley, “Beamforming: A Versatile Approach to Spatial Filtering,” IEEE ASSP Magazine, pp. 4–24, April 1988.

[7] M. Brandstein, and D. Ward, eds., Microphone Arrays: Signal Processing Techniques and Applications, Berlin, Germany: Springer-Verlag, 2001.

[8] D. E. Dudgeon, “Fundamentals of digital array processing,” Proc. IEEE, vol. 65, pp. 898–904, June 1977.