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

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.