Topic
Digital image correlation
About: Digital image correlation is a research topic. Over the lifetime, 7842 publications have been published within this topic receiving 132166 citations.
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TL;DR: In this paper, the authors present some preliminary results for the test/analysis/correlation of data measured using the 3D digital image correlation (DIC) approach along with traditional accelerometers and a scanning laser vibrometer for comparison to a finite element model.
374 citations
TL;DR: In this paper, a second-order approximation of the displacement gradients is proposed to directly measure both the first-and secondorder displacement gradient resulting from nonlinear deformation, which can be used to obtain more accurate strain measurements in large deformation situations.
Abstract: This paper outlines the procedure for refining the digital image correlation (DIC) method by implementing a second-order approximation of the displacement gradients. The second-order approximation allows the DIC method to directly measure both the first- and second-order displacement gradients resulting from nonlinear deformation. Thirteen unknown parameters, consisting of the components of displacement, the first- and second-order displacement gradients and the gray-scale value offset, are determined through optimization of a correlation coefficient. The previous DIC method assumes that the local deformation in a subset of pixels is represented by a first-order Taylor series approximation for the displacement gradient terms, so actual deformations consisting of higher order displacement gradients tend to distort the infinitesimal strain measurements. By refining the method to measure both the first- and second-order displacement gradients, more accurate strain measurements can be achieved in large-deformation situations where second-order deformations are also present. In most cases, the new refinements allow the DIC method to maintain an accuracy of ±0.0002 for the first-order displacement gradients and to reach ±0.0002 per pixel for the second-order displacement gradients.
370 citations
TL;DR: An extension to the basic concept of correlation detection as a means of image registration is developed that utilizes the spatial correlation within each image and greatly improves the detectability of image misregistration.
Abstract: An extension to the basic concept of correlation detection as a means of image registration is developed. The technique involves linear spatial preprocessing of the inages to be registered prior to the application of a correlation measure. This preprocessing operation utilizes the spatial correlation within each image and greatly improves the detectability of image misregistration. An analysis of the computational aspects of the algorithm is given. Also, results of a computer simulation to evaluate the technique are given.
366 citations
TL;DR: In this article, a method of determining stress intensity factors using digital image correlation is presented, and the experimental and analytical method is described with results for different specimen geometries given.
365 citations
TL;DR: In this article, a more general and practical intensity change model is employed with consideration of the linear intensity change of the deformed image, followed by an iterative least squares algorithm for calculating displacement field with sub-pixel accuracy.
362 citations