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Optical Engineering

Measurement of the defect size by shearography or other interferometric techniques
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Paper Abstract

Shearography is an interferometric technique suitable for detecting defects because they yield singular fringes and high phase values in wrapped and unwrapped phasemaps, respectively. We propose a methodology that leads to the defect size from unwrapped phasemap by extracting the size of the high phase values area. The area size is evaluated, thanks to a wavelet transform algorithm that enables the location of its borders. The performances of the methodology and of the algorithm have been tested by applying them on a defect where the size is known. An error less than 1.5% root mean square was reached. Our approach is independent of the shearing amount and of the phase profile, and it can be extended for other interferometric techniques.

Paper Details

Date Published: 6 April 2012
PDF: 8 pages
Opt. Eng. 51(3) 033602 doi: 10.1117/1.OE.51.3.033602
Published in: Optical Engineering Volume 51, Issue 3
Show Author Affiliations
Fabrice R. Michel, Univ. de Liège (Belgium)
Yvon L. Renotte, Univ. de Liège (Belgium)
Serge Habraken, Univ. de Liège (Belgium)

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