Multipole Source Capture Using Multiple Dictionary Sparse Bayesian Learning

A novel method of acoustic holography is introduced by expanding the equivalent source method (ESM) to include multipole equivalent sources and obtaining an optimal solution in a two-stage manner: Sparse Bayesian learning (SBL) is first used to estimate a broadband distribution of spherical harmonic sources, in which prior covariances for each frequency are transformed by its corrsponding dictionary. A per-frequency refinement is performed by a reduced-order inversion of the subset of sources. The estimated sources are able to be represented in a more compact manner and manipulated using common multipole techniques, such as higher-order Ambisonics (HOA). Simulated results for a finite quadrupole are obtained, and the reconstruction accuracy using several arrangements of spherical microphone arrays are compared.