半自由声场的全息重建和预测实验研究

Experimental study on the holographic reconstruction and prediction of semi-free field

半自由声场环境下的声源重建和声场预测研究对声全息技术走向实际应用具有非常重要的意义 .在提出基于分布源边界点法的半自由声场全息重建和预测方法的基础上 ,对此展开了实验研究 .并将重建和预测的结果与常规方法重建和预测的结果进行了比较和讨论 ,说明了重建预测过程中反射声压的影响和考虑反射声压的必要性 ,证明了所提出方法在解决半自由声场环境下存在地面反射时的声源重建和声场预测时的有效性和准确性 .还提出了采用奇异值截断滤波和Tikhonov正则化方法来削弱测量误差的影响 ,从而进一步优化了重建结果 。

The study on the holographic reconstruction and prediction of a semi-free field is valuable for the practical applications of the acoustic holography technique. On the basis of the proposed holographic reconstruction and prediction method of semi-free field in the inverse distributed source boundary point method,an experiment is carried out in a semi-free field. The reconstructed and predicted results in the proposed method are compared with those in the conventional method. The influence of the reflected sound in the reconstruction procedure is analyzed,and the effectiveness and correctness of the proposed method are validated. In addition,considering the sensitivity of the system equations to the measurement errors of pressures on the hologram surface in the experiment,the truncated singular value decomposition method and the Tikhonov regularization method are adopted to stabilize the problem. By choosing the appropriate regularization parameters and filter factors,the influence of errors can be decreased to the least,and the reconstructed and predicted quantities of acoustic field and the reliability of the holographic images are improved.