Extension of sound field reconstruction based on element radiation superposition method in a sparsity framework

Abstract

Nearfield acoustic holography (NAH) is a powerful tool for realizing source identification and sound field reconstruction. The wave superposition (WS)-based NAH is appropriate for the spatially extended sources and does not require the complex numerical integrals. Equivalent source method (ESM), as a classical WS approach, is widely used due to its simplicity and efficiency. In the ESM, a virtual source surface is introduced, on which the virtual point sources are taken as the assumed sources, and an optimal retreat distance needs to be considered. A newly proposed WS-based approach, the element radiation superposition method (ERSM), uses piston surface source as the assumed source with no need to choose a virtual source surface. To satisfy the application conditions of piston pressure formula, the sizes of pistons are assumed to be as small as possible, which results in a large number of pistons and sampling points. In this paper, transfer matrix modes (TMMs), which are composed of the singular vectors of the vibro-acoustic transfer matrix, are used as the sparse basis of piston normal velocities. Then, the compressive ERSM based on TMMs is proposed. Compared with the conventional ERSM, the proposed method maintains a good pressure reconstruction when the number of sampling points and pistons are both reduced. Besides, the proposed method is compared with the compressive ESM in a mathematical sense. Both simulations and experiments for a rectangular plate demonstrate the advantage of the proposed method over the existing methods.