Premium
Cross‐Correlation and Differential Technique Combination to Determine Displacement Fields
Author(s) -
Sousa A. M. R.,
Xavier J.,
Vaz M.,
Morais J. J. L.,
Filipe V. M. J.
Publication year - 2011
Publication title -
strain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.477
H-Index - 47
eISSN - 1475-1305
pISSN - 0039-2103
DOI - 10.1111/j.1475-1305.2010.00740.x
Subject(s) - digital image correlation , pixel , robustness (evolution) , displacement (psychology) , correlation coefficient , cross correlation , mathematics , similarity (geometry) , digital image , optical flow , measure (data warehouse) , planar , algorithm , computer vision , image (mathematics) , artificial intelligence , computer science , image processing , optics , mathematical analysis , physics , statistics , computer graphics (images) , data mining , psychology , biochemistry , chemistry , gene , psychotherapist
This study presents a method to measure the displacement fields on the surface of planar objects with sub‐pixel resolution, by combining image correlation with a differential technique. First, a coarse approximation of the pixel level displacement is obtained by cross‐correlation (CC). Two consecutive images, taken before and after the application of a given deformation, are recursively split in sub‐images, and the CC coefficient is used as the similarity measure. Secondly, a fine approximation is performed to assess the sub‐pixel displacements by means of an optical flow method based on a differential technique. To validate the effectiveness and robustness of the proposed method, several numerical tests were carried out on computer‐generated images. Moreover, real images from a static test were also processed for estimating the displacement resolution. The results were compared with those obtained by a commercial digital image correlation code. Both methods showed similar and reliable results according to the proposed tests.