Abstract
We present the capabilities of a recently developed inverse scheme for source localization at low frequencies within an arbitrary acoustic environment. The inverse scheme is based on minimizing a Tikhonov functional matching measured microphone signals with simulated ones. We discuss the sensitivity of all involved parameters, the precision of geometry and physical boundary modeling for the numerical simulation using the finite element (FE) method, and the automatic determination of the positions of the recording microphones being distributed around the object of investigation. Finally, we apply the inverse scheme to a real-world scenario and compare the obtained results to state-of-the-art signal processing approaches, e.g. Clean-SC.
Highlights
The knowledge about position and distribution of sound sources is necessary for taking actions in noise reduction
A modification of this classic approach is delivered by functional beamforming (FuncBF) [2, 3], which leads to an improvement of resolution and dynamic range, while the computational cost remains almost the same as in the standard approach
The applicability of the inverse scheme towards computational time is mainly restricted to the low frequency range, since the discretization effort and the number of degree of freedoms in 3D is of the order OðeÀsiz3eÞ, where esize is the mesh size being determined by esize c0 N e fmax
Summary
The knowledge about position and distribution of sound sources is necessary for taking actions in noise reduction. Thereby, a common technique is acoustic beamforming which can be used to determine the source position and distribution as well as the source strength This technique is based on evaluating simultaneously recorded sound pressure data from microphone array measurements. A comprehensive overview of different acoustic imaging methods can be found in [8, 13, 14] Despite these advances in beamforming techniques, it has to be mentioned that major limitations are caused by the source model. To overcome the above mentioned limitations, an inverse scheme has been developed [20], which fully solves the Helmholtz equation using the finite element (FE) method with the correct boundary conditions This approach is used in combination with microphone array measurements to localize and quantify low-frequency sound sources.
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