Yu Liang, Guo Qixin, Chu Ning, Wang Rui
Institute of Vibration, Shock and Noise, State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China.
College of Electronics and Information Engineering, Tongji University, Shanghai 201804, China.
Sensors (Basel). 2020 Dec 19;20(24):7308. doi: 10.3390/s20247308.
Beamforming technology is an essential method in acoustic imaging or reconstruction, which has been widely used in sound source localization and noise reduction. The beamforming algorithm can be described as all microphones in a plane simultaneously recording the source signal. The source position is then localized by maximizing the result of the beamformer. Evidence has shown that the accuracy of the sound source localization in a 2D plane can be improved by the non-synchronous measurements of moving the microphone array. In this paper, non-synchronous measurements are applied to 3D beamforming, in which the measurement array envelops the 3D sound source space to improve the resolution of the 3D space. The entire radiated object is covered better by a virtualized large or high-density microphone array, and the range of beamforming frequency is also expanded. The 3D imaging results are achieved in different ways: the conventional beamforming with a planar array, the non-synchronous measurements with orthogonal moving arrays, and the non-synchronous measurements with non-orthogonal moving arrays. The imaging results of the non-synchronous measurements are compared with the synchronous measurements and analyzed in detail. The number of microphones required for measurement is reduced compared with the synchronous measurement. The non-synchronous measurements with non-orthogonal moving arrays also have a good resolution in 3D source localization. The proposed approach is validated with a simulation and experiment.
波束形成技术是声学成像或重建中的一种重要方法，已广泛应用于声源定位和降噪。波束形成算法可以描述为平面中的所有麦克风同时记录源信号。然后通过最大化波束形成器的结果来定位源位置。有证据表明，通过移动麦克风阵列的非同步测量可以提高二维平面中声源定位的精度。本文将非同步测量应用于三维波束形成，其中测量阵列包围三维声源空间以提高三维空间的分辨率。通过虚拟的大型或高密度麦克风阵列可以更好地覆盖整个辐射物体，并且波束形成频率范围也得到了扩展。通过不同方式实现三维成像结果：使用平面阵列的传统波束形成、使用正交移动阵列的非同步测量以及使用非正交移动阵列的非同步测量。将非同步测量的成像结果与同步测量进行比较并详细分析。与同步测量相比，所需的测量麦克风数量减少。使用非正交移动阵列的非同步测量在三维源定位中也具有良好的分辨率。所提出的方法通过仿真和实验得到了验证。
