Table of Contents
ISRN Mechanical Engineering
Volume 2013, Article ID 241958, 11 pages
http://dx.doi.org/10.1155/2013/241958
Research Article

Scan and Paint: Theory and Practice of a Sound Field Visualization Method

1Microflown Technologies, Tivolilaan 205, 6824 BV Arnhem, The Netherlands
2Institute of Sound and Vibration Research, University of Southampton, Southampton SO17 1BJ, UK

Received 23 June 2013; Accepted 24 July 2013

Academic Editors: Y. Chen and Y. Zhang

Copyright © 2013 Daniel Fernández Comesaña et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Sound visualization techniques have played a key role in the development of acoustics throughout history. The development of measurement apparatus and techniques for displaying sound and vibration phenomena has provided excellent tools for building understanding about specific problems. Traditional methods, such as step-by-step measurements or simultaneous multichannel systems, have a strong tradeoff between time requirements, flexibility, and cost. However, if the sound field can be assumed time stationary, scanning methods allow us to assess variations across space with a single transducer, as long as the position of the sensor is known. The proposed technique, Scan and Paint, is based on the acquisition of sound pressure and particle velocity by manually moving a P-U probe (pressure-particle velocity sensors) across a sound field whilst filming the event with a camera. The sensor position is extracted by applying automatic color tracking to each frame of the recorded video. It is then possible to visualize sound variations across the space in terms of sound pressure, particle velocity, or acoustic intensity. In this paper, not only the theoretical foundations of the method, but also its practical applications are explored such as scanning transfer path analysis, source radiation characterization, operational deflection shapes, virtual phased arrays, material characterization, and acoustic intensity vector field mapping.