Department of Electrical Engineering, Technical University of Denmark, Orsteds Plads 352, DK-2800 Kongens Lyngby, Denmark.
J Acoust Soc Am. 2013 Sep;134(3):2078-89. doi: 10.1121/1.4816545.
During the last decade, the aeroacoustic community has examined various methods based on deconvolution to improve the visualization of acoustic fields scanned with planar sparse arrays of microphones. These methods assume that the beamforming map in an observation plane can be approximated by a convolution of the distribution of the actual sources and the beamformer's point-spread function, defined as the beamformer's response to a point source. By deconvolving the resulting map, the resolution is improved, and the side-lobes effect is reduced or even eliminated compared to conventional beamforming. Even though these methods were originally designed for planar sparse arrays, in the present study, they are adapted to uniform circular arrays for mapping the sound over 360°. This geometry has the advantage that the beamforming output is practically independent of the focusing direction, meaning that the beamformer's point-spread function is shift-invariant. This makes it possible to apply computationally efficient deconvolution algorithms that consist of spectral procedures in the entire region of interest, such as the deconvolution approach for the mapping of the acoustic sources 2, the Fourier-based non-negative least squares, and the Richardson-Lucy. This investigation examines the matter with computer simulations and measurements.
在过去的十年中，航空声学领域研究了各种基于反卷积的方法，以改善使用平面稀疏麦克风阵列扫描的声场的可视化效果。这些方法假设观测平面中的波束形成图可以通过实际声源的分布和波束形成器的点扩散函数（定义为波束形成器对点源的响应）的卷积来近似。通过对得到的图进行反卷积，可以提高分辨率，与传统波束形成相比，降低或甚至消除了旁瓣效应。尽管这些方法最初是为平面稀疏阵列设计的，但在本研究中，它们被适应于用于 360°声映射的均匀圆形阵列。这种几何形状的优点在于，波束形成输出实际上与聚焦方向无关，这意味着波束形成器的点扩散函数是位移不变的。这使得可以应用计算效率高的反卷积算法，这些算法在整个感兴趣区域内包括谱处理，例如用于声源映射的反卷积方法 2、基于傅里叶的非负最小二乘法和 Richardson-Lucy。本研究通过计算机模拟和测量来研究这个问题。
