Abstract
Near-field acoustical holography (NAH) based on the equivalent source method (ESM) is an efficient method applied for noise source identification. Asl2-norm-based regularization cannot produce a satisfactory solution of the ill-conditioned problem in high frequency, the conventional ESM is restricted to relatively low frequency, and the resolution of conventional ESM in middle to high frequency remains a limitation open to investigation. This article presents an algorithm known as improved functional equivalent source method (IFESM), designed to enhance the resolution of conventional ESM. This method is developed in the framework of wideband acoustical holography (WBH) combining with functional beamforming (FB). Through numerical simulations, it is proved that the proposed method can localize noise with higher resolution compared with WBH and conventional ESM, and the ghosts on noise source map can be suppressed effectively. The validity and the feasibility of the proposed method are manifested by experiments including single-source and coherent-source localization.
Highlights
Since near-field acoustic holography (NAH) was first proposed by Williams et al [1,2,3] in 1980s, it has been widely studied by the worldwide scholars
The equivalent source method (ESM), which is a kind of NAH reconstruction algorithm for sound sources with arbitrary shape, has some particular advantages such as robust calculation, fast speed, and easy implementation [4, 5]
The reconstruction accuracy of wideband acoustical holography (WBH) is much better than conventional ESM in middle to high frequency
Summary
Since near-field acoustic holography (NAH) was first proposed by Williams et al [1,2,3] in 1980s, it has been widely studied by the worldwide scholars. Suzuki [16] published a similar method, but he used a monopole/dipole point source model of the same type as ESM, and he enforced sparsity in the source model by use of l1-norm penalty on the solution vector. Hald [21] proposed wideband acoustical holography method (WBH), in which the gradient iteration algorithm containing a dynamic filter process is employed to find the sparse solution of equivalent source amplitude. Compared with the conventional ESM with l2-norm-based regularization, WBH uses a dedicated iterative solver that enforces sparsity in the monopole source model. In this way, the reconstruction accuracy of WBH is much better than conventional ESM in middle to high frequency. It is proved that iWBH can reconstruct noise source with better accuracy than WBH, and the proposed method can localize noise sources more accurately in middle to high frequency
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
