考虑边界声阻抗的声场分离算法

A sound field separation algorithm in consideration of boundary acoustic impedance

在非自由声场环境下近场声全息技术的应用需要配合声场分离算法,而现有的处理反射声场的分离算法大部分研究的是理想化的边界条件,对于阻抗反射边界的研究较少。为弥补这一不足,提出一种考虑反射边界声阻抗的声场分离算法。该算法先利用系列球面谐波基函数的叠加来描述目标声源的直达声场,再结合镜像法并考虑反射边界声阻抗来描述镜像声源的反射声场,两者相加得到混合声场的声压值。利用传声器阵列上得到的声压测量信号,求解出目标源的球面谐波基函数系数,最后重构声场实现直达声与反射声的分离。通过Comsol和Matlab进行仿真实验来检验该算法的有效性。结果表明在各种边界阻抗条件下,该算法均能较好地完成直达声与反射声的分离,且分离精度较高。

The application of near field acoustic holography needs to be combined with sound field separation algorithm.The existing separation algorithms dealing with reflected sound field mostly study idealized boundary conditions,but the research on impedance reflection boundary is rare.In order to make up for this shortcoming,an acoustic field separation algorithm considering the acoustic impedance of reflected boundary is proposed.In this algorithm,the direct sound field of the target source is described by the superposition of a series of spherical harmonic basis functions.In combination with the mirror image method and considering the reflection boundary acoustic impedance,the reflection acoustic field of the mirror source is described by the superposition of a series of spherical harmonic basis functions,and the sound pressure value of the mixed acoustic field is obtained by adding them.Then,the spherical harmonic basis function coefficient of the target source is solved by using the sound pressure measurement signal obtained from the microphone array.Finally,the sound field is reconstructed to realize the separation of direct sound and reflected sound.Simulation experiments with Comsol and Matlab are conducted to verify the effectiveness of the algorithm.The results show that the proposed algorithm can separate the direct sound and the reflected sound well under various boundary impedances,and the separation accuracy is high.