Regularization for improving the deconvolution in real-time near-field acoustic holography.
Regularization for improving the deconvolution in real-time near-field acoustic holography.
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DOI：
10.1121/1.3586790
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发表时间：
2011-06
期刊：
影响因子：
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通讯作者：
S. Paillasseur;Jean-Hugh Thomas;J. Pascal
中科院分区：
文献类型：
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作者：
S. Paillasseur;Jean-Hugh Thomas;J. Pascal
近场声全息术是一种测量过程，用于根据由声源平面的近场中的麦克风阵列进行的测量来定位和表征静止声源。一种称为实时近场声全息（RT-NAH）的技术已被引入到非平稳源的情况下扩展这种方法。这种技术是基于一个公式，它描述了时间相关的声压信号在前向平面上的传播使用卷积产品与脉冲响应在时间-波数域。因此，通过反褶积获得压力场的向后传播。在RT-NAH中考虑倏逝波提高了解的空间分辨率，但使反卷积问题“不适定”，并且经常产生不适当的解。本文的目的是集中解决这个反卷积问题。两种反卷积方法进行了比较：一个使用奇异值分解和标准的Tikhonov正则化，另一个是基于最佳维纳滤波。涉及由非平稳信号驱动的单极子的模拟通过客观指标证明了随时间变化的重建声场的准确性。结果突出了使用正则化的优点，特别是在存在测量噪声的情况下。
Near-field acoustic holography is a measuring process for locating and characterizing stationary sound sources from measurements made by a microphone array in the near-field of the acoustic source plane. A technique called real-time near-field acoustic holography (RT-NAH) has been introduced to extend this method in the case of nonstationary sources. This technique is based on a formulation which describes the propagation of time-dependent sound pressure signals on a forward plane using a convolution product with an impulse response in the time-wavenumber domain. Thus the backward propagation of the pressure field is obtained by deconvolution. Taking the evanescent waves into account in RT-NAH improves the spatial resolution of the solution but makes the deconvolution problem "ill-posed" and often yields inappropriate solutions. The purpose of this paper is to focus on solving this deconvolution problem. Two deconvolution methods are compared: one uses a singular value decomposition and a standard Tikhonov regularization and the other one is based on optimum Wiener filtering. A simulation involving monopoles driven by nonstationary signals demonstrates, by means of objective indicators, the accuracy of the time-dependent reconstructed sound field. The results highlight the advantage of using regularization and particularly in the presence of measurement noise.