A partial field decomposition algorithm and its examples for near-field acoustic holography

Abstract

In this paper we introduce a practical algorithm that can accurately implement partial field decomposition for near-field acoustic holography (NAH). Unlike other methods, the algorithm does not require sensors near sources because it uses calculations rather than measured signals in order to decompose a holography image into the images of individual sources. Therefore it makes holography measurement easier than other methods. The algorithm is composed of five steps: measurement of pressure on a hologram plane, estimation of pressure on a source plane, selection of maximum pressure, estimation of the sound field from one source, and estimation of the remaining sound field. In this paper we also report two experiments that verify and demonstrate the algorithm. In one experiment six speakers are operated independently. The other is a vortex shedding experiment. Their results show that the decomposition method is useful for identifying hidden sources and estimating the power of individual sources.