传播波与倏逝波对全息重建影响的研究

通过分析近场声全息中传播波和倏逝波的声场分布与声源大小、辐射频率及测量距离的关系,得出了传播波和倏逝波在空间声场中的变化规律、影响因素以及两者之间的对应关系,确定了可利用的倏逝波传播距离。在此基础上,提出了一种改进的远场声全息方法：首先利用传统远场声全息方法重建声源,然后通过传播波与倏逝波的关系,得出声源面上相应的倏逝波成分,两者叠加获取接近于近场声全息的重建结果。最后,通过仿真和实验验证了这一结果。

Research on evanescent wave and propagation wave in sound field and the improved acoustic holography method

The relation between the distributions of propagating plane wave and evanescent wave and the acoustic field characteristics (such as source radius, sound radiation frequency and measure distance) is analyzed in acoustic holo-gram. On the basis of the above analysis, the influencing factor and the change law of the propagating plane wave and the evanescent wave in acoustic field are studied and summarized. An available propagation distance of the evanescent wave is determined. An improved far-field acoustic holography which can be used to reconstruct the propagating plane wave is presented. Then the evanescent wave in acoustic field is calculated by their relationship between the propagating plane wave and the evanescent wave so as to reconstruct acoustic field. By using this method, the evanescent wave components can be getting fully utilized in far-field acoustical holography technology, thus the source is identified and located more precisely. Finally, the analysis results and the proposed method are verified by a simulation and an experiment.