Method for reconstructing an acoustic field

Abstract

Disclosed herein is a method of reconstructing a sound field. The method comprises receiving measured values indicative of a first acoustic quantity measured at a set of measurement locations; defining a set of virtual source locations; and computing a second acoustic quantity for at least one target location from one or more wave functions each representative of a respective sound field originating from a respective one of the defined set of virtual source locations; wherein the one or more wave functions are weighted by respective one or more weighting factors, and wherein computing comprises determining the one or more weighting factors from a least-norm fit of the one or more wave functions to the received measured values.

Description

technical field [0001] The invention relates to the reconstruction of acoustic fields. Background technique [0002] Near-field Acoustical Holography (NAH) is a very useful tool for 3D visualization of acoustic radiation and precise noise source localization based on measurements on surfaces near the sound source. Its ability to reconstruct also evanescent wave components ensures very high spatial resolution. [0003] Known near-field acoustic holography methods are based on regular-grid measurements across level surfaces in a separable coordinate system, allowing the NAH calculation to be performed by the spatial discrete Fourier transform (DFT), See, eg, "Sound source reconstruction using a microphone array," by E. G. Williams, J. D. Maynard, and E. J. Skudrzyk, J. Acoust. Soc. Am. 68, 340-344 (1980). Due to the use of DFT, the processing is very fast, but side effects of using DFT include severe spatial windowing effects unless the measurement area completely covers the...

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Problems solved by technology

However, since only spherical wave functions with a common origin are used to represent the sound field, errors will be introduced in the reconstruction of the sound field on the source surface unless the source surface is also spherical and centered at the same origin

Another disadvantage of the prior art method described above is that it requires a large number of measurement locations to obtain a sufficiently accurate model

The third disadvantage is that traditional regularization methods (such as Tikhonov regularization) do not work correctly

However, this prior art method is based on a plane wave function and does not consider the exact reconstruction of the acoustic field on a non-planar source surface

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