Partial source discrimination in near field acoustic holography

Abstract Decomposition techniques based on principal component analysis (PCA) and partial coherent output power (PCOP) analysis are applied to scanning near field acoustic holography (NAH) in order to identify partial sources. Where location of partial sources is uncertain, inaccessible, or the underlying physical process is not well understood, reference transducers may produce outputs which are not independent. It is shown that intercorrelated references can restrict the decomposition process using PCA. Under these circumstances PCOP analysis provides a valuable additional tool for an understanding of the physical model.