近场声全息测量研究

本文探讨了进行近场声全息测量时需要考虑的问题。文中指出全息测量面到声源重建面的距离应在最小波长范围内，并且与系统的动态范围和空间分辨率有关，传声器之间的间距应不大于最小波长的二分之一，传声器阵所扫描的全息测量面的尺寸至少为最大波长的一倍以上。参考传声器须放置在非相干声源附近，数目不应小于非相干声源的数目。测量的数据需要进行波数域滤波，提高信噪比，改善重建精度。

Research on Nearfield Acoustical Holography Measurement

Some practical issues to be considered when making NAH measurement were discussed. This paper pointed out that the standoff from measurement plane to reconstruction plane may as well be within the minimum wavelength, it also has relations with the dynamic range of the measurement system and spatial resolution, and microphone spacing can not exceed a half wavelength of the maximum frequency of interest, the size of holographic measurement surface should be one or more times of the maximum wavelength. Reference microphones need be placed near the incoherent sources, the number has to be more than that of the latter. The measured data require being filtered in wavenumber domain, resulting in an improved signal-to-noise ratio and higher reconstruction accuracy.