Acquisition of bi-directional reflectance functions by Nearfield Acoustical Holography – a preliminary study

Hargreaves, JA ORCID: https://orcid.org/0000-0003-4736-7507 2019, Acquisition of bi-directional reflectance functions by Nearfield Acoustical Holography – a preliminary study , in: International Congress on Acoustics 2019, 9th - 13th September 2019, Aachen.

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Abstract

It is well known that material absorption and scattering is dependent on incidence and observation angle. Despite this, the corresponding standardised coefficients, which are used to represent these mechanisms within computational acoustic models, aggregate all such dependency into single random-incidence parameters. This limits the accuracy that can be achieved with computational acoustic models – even if these algorithms were to capture the wave physics perfectly, which they often do not, the results would not match physical reality because the input data is too low resolution. Bi-Directional Reflectance Functions are an established way of describing boundary absorption and scattering in computer graphics that have been suggested for use in acoustics. To date, several algorithms have been published that do or could use these in simulation, but no measurement methods are available to acquire them. There is also ambiguity over some aspects of their definition e.g. whether finite panel size is included as a scattering mechanism. This paper adopts a definition suitable for high-frequency Boundary Element Method algorithms that use oscillatory basis functions to capture wave directions. It then proposes an acquisition method based on double-layer Near-Field Acoustical Holography and assesses it accuracy using 2D simulations.

Item Type: Conference or Workshop Item (Lecture)
Schools: Schools > School of Computing, Science and Engineering > Salford Innovation Research Centre
Journal or Publication Title: Proceedings of the ICA 2019 AND EAA EUROREGIO
Publisher: DEUTSCHE GESELLSCHAFT FÜR AKUSTIK
ISBN: 9783939296157
ISSN: 2226-7808
Related URLs:
Depositing User: Dr Jonathan Hargreaves
Date Deposited: 03 Sep 2019 08:38
Last Modified: 04 Dec 2019 10:41
URI: http://usir.salford.ac.uk/id/eprint/52260

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