Near-field acoustic holography with three-dimensional scanning measurements

Abstract

Data acquisition is one of the key steps in near-field acoustic holography. Most of the existing measurement methods become time-consuming or even impractical when the total number of measurement points is excessively large, for example for the sound field reconstruction of a large-scale source or for a mid-high frequency problem. Alternatively, a three-dimensional scanning near-field acoustic holography (3DSNAH) method is hereby proposed to overcome such problems providing the sound field is time stationary. Data measurement at a large number of points can be accomplished in a matter of minutes by using scanning measurements to acquire the holographic data. The data is then used in an inverse boundary element method to obtain a detailed reconstruction of the sound field radiated by the sound source. Comparison with the traditional point-by-point measurement method demonstrates that the proposed method can acquire holographic data of good quality and reconstruct the sound field with a reasonable accuracy, which verifies the feasibility of the 3DSNAH.