CORRELIQ4: A Software for “Finite-element” Displacement Field Measurements by Digital Image Correlation

This internal report completes the first ones (i.e., no. 230 and 254) on digital image correlation. The technique developed herein is based upon a multi-scale approach to determine “finite ele-ment ” displacement fields by digital image correlation. The displacement field is first estimated on a coarse resolution image and progressively finer details are introduced in the analysis as the displacement is more and more securely and accurately determined. Such a scheme has been developed to increase the robustness, accuracy and reliability of the image matching algorithm. The details of the program are then presented. The procedure, CORRELIQ4, is implemented in MatlabTM. The different steps are presented. The procedure is used on one example deal-ing with Portevin-Le Châtelier bands in an aluminum alloy, and with an artificially deformed picture of stone wool. Other published applications using the present code are listed. The software has been protected under the IDDN.FR.001.110004.000.S.P.2008.000.21000. Résume ́ : rapport interne n ◦ 269 Ce rapport interne complète les précédents (i.e., n ◦ 230 et 254) sur la corrélation d’images numériques. La technique présentée ici est basée sur une détermination multi-échelles par corrélation d’images d’un champ de déplacement de type “élément fini”. Le champ de déplace