標題: Optimal two-layer directive microphone array with application in near-field acoustical holography
作者: Bai, Mingsian R.
Wang, Chunkai
Juan, Shen-Wei
機械工程學系
Department of Mechanical Engineering
公開日期: 1-Aug-2012
摘要: Conventional near-field acoustical holography (NAH) is generally based on the free-field assumption, which can cause errors when interfering sources are present in practical environments. To cope with this problem, previous research suggested a combined pressure-velocity approach for NAH that provides certain advantages to rejection of interferences. This paper revisits this idea in a broader context of optimal array design and examines the feasibility of using unidirectional microphones in each channel of the array such that the robustness of inverse reconstruction is enhanced against interfering sources. As indicated in the simulation, the numerical noise in finite difference estimation of particle velocity can nullify the advantage of the well-conditioned velocity-based reconstruction. In the proposed approach, the characteristics of each array channel consisting of two microphones are tailored by taking into account not only the directivity, but also the robustness against self-noise. An objective function based on directivity index and white noise gain is exploited in a linear quadratic optimization of a two-element end-fire array. The proposed optimal array is validated in conjunction with the equivalent source model (ESM) -based NAH through numerical simulations, with an interfering source positioned behind the array. The results have shown the directive optimal array has yielded improved quality of images in comparison with conventional approaches in the presence of an interfering source and sensor noise. (C) 2012 Acoustical Society of America. [http://dx.doi.org/10.1121/1.4734238]
URI: http://dx.doi.org/10.1121/1.4734238
http://hdl.handle.net/11536/16920
ISSN: 0001-4966
DOI: 10.1121/1.4734238
期刊: JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
Volume: 132
Issue: 2
起始頁: 862
結束頁: 871
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