Bi Chuan-Xing, Chen Xin-Zhao, Chen Jian
Institute of Sound and Vibration Research, Hefei University of Technology, Hefei 230009, People's Republic of China.
J Acoust Soc Am. 2008 Mar;123(3):1472-8. doi: 10.1121/1.2837489.
A technique for separating sound fields using two closely spaced parallel measurement surfaces and based on equivalent source method is proposed. The method can separate wave components crossing two measurement surfaces in opposite directions, which makes nearfield acoustic holography (NAH) applications in a field where there exist sources on the two sides of the hologram surface, in a reverberant field or in a scattered field, possible. The method is flexible in applications, simple in computation, and very easy to implement. The measurement surfaces can be arbitrarily shaped, and they are not restricted to be regular as in the traditional field separation technique. And, because the method performs field separation calculations directly in the spatial domain-not in the wave number domain--it avoids the errors and limitations (the window effects, etc.) associated with the traditional field separation technique based on the spatial Fourier transform method. In the paper, a theoretical description is first given, and the performance of the proposed field separation technique and its application in NAH are then evaluated through experiments.
提出了一种基于等效源法，利用两个紧密间隔的平行测量面来分离声场的技术。该方法能够分离沿相反方向穿过两个测量面的波分量，这使得近场声全息（NAH）在全息图表面两侧存在声源的场中、混响场或散射场中的应用成为可能。该方法应用灵活，计算简单，且极易实现。测量面可以是任意形状，不像传统场分离技术那样局限于规则形状。并且，由于该方法直接在空间域而非波数域进行场分离计算，所以避免了与基于空间傅里叶变换方法的传统场分离技术相关的误差和局限性（如窗口效应等）。本文首先给出了理论描述，然后通过实验评估了所提出的场分离技术的性能及其在NAH中的应用。
