聲源法結合波束成形與正規化法于聲音全像之發展研究

COMBINATION OF BEAM-FORMING, REGULARIZATION AND SIMILAR SOURCE METHOD (BRSSM) CONDITION FOR ACOUSTIC HOLOGRAPHY

Similar source method (SSM) has been developed to describe interior and exterior sound field by Too. It is based onthe imaginary monopole source distribution which is one of the equivalent source methods. In the present study, atechnique based on beam-forming approach and similar source method (BSSM) for reconstructing sound field in theacoustic holography is developed. The procedure is to search the source location by using beam-forming approach first.Then, similar source method is used to reconstruct the sound field. Since BSSM has some difficulties when measuringprocess with noise is considered. BRSSM, a new approach which combines beam-forming, Tikhonov regularization andSSM for acoustic holograph is developed to avoid the effect of noise. In BRSSM, regularization process and an optimalregularization parameter are used to avoid the singularity effect from noise in the inverse matrix calculation of SSM.Finally, several simulations and experimentations are shown to verify this approach in the present study. 涂所發展的近似聲源法是屬於等效聲源法的一種，此方法是利用均勻分布的點聲源來描述任何內部與外部聲場。本研究將發展一種新的聲場重建技術，此技術將以近似聲源法為基礎，並結合波束合成與正規化法。首先利用波束合成法搜尋聲源位置，再以近似聲源法來重建聲場。考慮到實際量測通常會包含雜訊，因此在聲源法的反算過程中加入正規化法，避免在反算過程因雜訊而造成發散的問題。最後本研究將以模擬及實驗，證明此方法之可行性。