低信噪比条件下的平面等效源近场声全息方法

为提高低信噪比条件下的近场声全息成像效果,提出一种低信噪比条件下的平面等效源近场声全息方法,其将近场声全息对声场还原度高的优点和声源定位方法抗干扰能力强的优点相结合。该方法首先结合压缩感知技术的正交匹配追踪算法,在未知声源数目情况下求出虚拟声源在平面分布,再利用传导矩阵求出近场平面声压分布。通过仿真分析金属弹性材料壳体振动的近场声辐射,将该方法与Fourier变换方法、常规边界元方法以及传统等效源方法的近场声全息效果相比较。仿真实验表明,该方法性能可靠且具有较强的抗噪能力,可作为低信噪比条件下平面近场声全息方法的一种有效补充。

The Planar Near-Field Acoustical Holography Based on the Equivalent Source Method with Low Signal-to-Noise Ratio

In order to improve the performance of near-field acoustic holography in the condition of low signal-to-noise ratio, a planar near-field acoustical holography method was proposed based on equivalent source method. The method combined the advantages of the near-field acoustic holography and the sound source localization, namely a high restoring-degree of the sound field and great resistance to interference. The method adopted the orthogonal matching pursuit algorithm of the compressed sensing technology, obtained the virtual sound source distribution without knowing the exact number of the unknown sound sources, and employed the conduction matrix to decipher the sound pressure distribution of the holographic surface. The comparison between the method and the Fourier transform method, the conventional boundary element method and the conventional plane-based equivalent source method in terms of the holographic effect was conducted in an analysis simulating the near-field acoustic radiation of metal elastic material shell. The results showed that the proposed method was reliable and highly noise-resistant. It could serve as an effective supplement to the near-field acoustic holography method in the condition of low signal-to-noise ratio.