Traceable technique for an in situ full field in-plane measurement validation of digital image correlation

Eszter Szigeti; Matthew Loparco; Evgeni Todorov; Shelby Wheatley; Richard John Greene

doi:10.1117/1.OE.56.3.033101

2 March 2017 Traceable technique for an in situ full field in-plane measurement validation of digital image correlation

Eszter Szigeti, Matthew Loparco, Evgeni Todorov, Shelby Wheatley, Richard John Greene

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Optical Engineering, Vol. 56, Issue 3, 033101 (March 2017). https://doi.org/10.1117/1.OE.56.3.033101

Abstract

For digital image correlation to be firmly accepted as a validated displacement measurement system in the industrial arena, a measurement must be captured by the analysis system at time of test which confirms that the image correlation hardware and software system is performing as expected. To this end, a method for validating stereo digital image correlation optical test setups is presented, which is traceable to the length standard. The method employs a screen, on which is displayed a randomized speckle pattern of appropriate pitch for the test in question. This speckle pattern is then artificially translated by a known number of pixels on the screen, and image pairs captured of the original and translated speckles. Processing of these data image pairs with image correlation, and calibration of the pixel pitch of the display screen using a traceable measurement system, allows the image correlation test setup to be traceably calibrated in terms of in-plane displacement. The method is shown to be sufficiently sensitive and repeatable to provide a reasonably accurate, traceable validation in a practical environment.

CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Eszter Szigeti, Matthew Loparco, Evgeni Todorov, Shelby Wheatley, and Richard John Greene "Traceable technique for an in situ full field in-plane measurement validation of digital image correlation," Optical Engineering 56(3), 033101 (2 March 2017). https://doi.org/10.1117/1.OE.56.3.033101

Received: 10 October 2016; Accepted: 9 February 2017; Published: 2 March 2017

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