Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2133, USA.
J Acoust Soc Am. 2012 Jan;131(1):292-302. doi: 10.1121/1.3664089.
Acoustic diffraction allows sound to travel around opaque objects and therefore may allow beyond-line-of-sight sensing of remote sound sources. This paper reports simulated and experimental results for localizing sound sources based on fully shadowed microphone array measurements. The generic geometry includes a point source, a solid 90° wedge, and a receiving array that lies entirely in the shadow defined by the source location and the wedge. Source localization performance is assessed via matched-field (MF) ambiguity surfaces as a function of receiving array configuration, and received signal-to-noise ratio for the Bartlett and minimum variance distortionless (MVD) MF processors. Here, the sound propagation model is developed from a Green's function integral treatment. A simple 16 element line array of microphones is tested in three mutually orthogonal orientations. The experiments were conducted using an approximate 50-to-1-scaled tabletop model of a blind city-street intersection and produced ambiguity surfaces from source frequencies between 17.5 and 19 kHz that were incoherently summed. The experimental results suggest that a sound source may be localized by the MVD processor when using fully shadowed arrays that have significant aperture parallel to the edge of the wedge. However, this performance is reduced significantly for signal-to-noise ratios below 40 dB.
声衍射使得声音能够绕过不透明物体传播，因此可能允许对远程声源进行超视距感应。本文报告了基于完全遮蔽的麦克风阵列测量进行声源定位的模拟和实验结果。通用几何形状包括一个点声源、一个 90°的实心楔形物和一个完全位于源位置和楔形物定义的阴影中的接收阵列。通过匹配场 (MF) 模糊表面评估源定位性能，作为接收阵列配置的函数，以及 Bartlett 和最小方差无失真 (MVD) MF 处理器的接收信号噪声比。在这里，声传播模型是从格林函数积分处理中开发出来的。一个简单的 16 元素麦克风线阵在三个相互正交的方向上进行了测试。实验是在一个近似 50:1 比例的盲城市街道交叉口桌面模型上进行的，产生了来自 17.5 到 19 kHz 之间的声源频率的模糊表面，这些表面是不相干地相加的。实验结果表明，当使用与楔形物边缘平行的具有显著孔径的完全遮蔽阵列时，MVD 处理器可以对声源进行定位。然而，当信噪比低于 40 dB 时，这种性能会显著降低。
