单层传声器阵列重建相干声场的近场声全息方法研究

针对传声器阵列两侧存在相干声源的非自由声场重建问题,提出基于球面谐波函数扩展近场声全息理论的相干声场重建方法。该方法在已知测量面两侧声源几何位置时,使用单层传声器阵列获取测量面处的声压分布,通过最小二乘法获得与目标声源和干扰噪声源响应对应的最优球波函数扩展项数和最优系数向量,结合测点位置的空间坐标进行声波分解,并分别重建出各声源在测量面上的声压分布。为了验证方法的有效性,分别给出了相干噪声源为球形声源和非球形声源的仿真验证,并在全消声室内对双扬声器产生的相干声场的重建进行了实验验证。结果表明:该方法对球形声源和非球形声源干扰下的声场重建都具有较好的效果,球形声源干扰下的重建精度更高。 

Near-field acoustic holography based reconstruction of sound field with coherent sound sources by single layer microphone array

A methodology of separation and reconstruction on holography surface of sound field caused by coherent sound sources based on spherical wave expansion based near-field acoustic holography is presented. A single layer microphone array is used to obtain the sound pressure on the measurement plane, the least-square method is applied to solve the coefficient vectors corresponding to the coherent sound sources. With the coordinates of the measurement points and the position information of the sound sources, the sound pressure on the measurement points sound source can be reconstructed, respectively. The methodology is validated and the accuracy of wave separation and sound field reconstruction is examined numerically in sound field with coherent spherical source and non-spherical source. The accuracy of reconstruction is also examined in anechoic chamber with two coherent speakers. The results of experiment show that the accuracy of reconstruction of sound field with spherical sources is higher than that with non-spherical source.