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Published April 2022 | public
Journal Article

DIC Challenge 2.0: Developing Images and Guidelines for Evaluating Accuracy and Resolution of 2D Analyses


Background: The DIC Challenge 2.0 follows on from the work accomplished in the first Digital Image Correlation (DIC) Challenge Reu et al. (Experimental Mechanics 58(7):1067, 1). The second challenge was required to better quantify the spatial resolution of 2D-DIC codes. Objective: The goal of this paper is to outline the methods and images for the 2D-DIC community to use to evaluate the performance of their codes and improve the implementation of 2D-DIC. Methods: This paper covers the creation of the new challenge images and the analysis and discussion of the results. It proposes a method of unambiguously defining spatial resolution for 2D-DIC and explores the tradeoff between displacement and strain noise (or measurement noise) and spatial resolution for a wide variety of DIC codes by a combination of the images presented here and a performance factor called Metrological Efficiency Indicator (MEI). Results: The performance of the 2D codes generally followed the expected theoretical performance, particularly in the measurement of the displacement. The comparison did however show that even with fairly uniform displacement performance, the calculation of the strain spatial resolution varied widely. Conclusions: This work provides a useful framework for understanding the tradeoff and analyzing the performance of the DIC software using the provided images. It details some of the unique errors associated with the analysis of these images, such as the Pattern Induced Bias (PIB) and imprecision introduced through the strain calculation method. Future authors claiming improvements in 2D accuracy are encouraged to use these images for an unambiguous comparison.

Additional Information

© Society for Experimental Mechanics 2021. Received 20 October 2021; Accepted 27 October 2021; Published 04 January 2022. The 2D-DIC Challenge is dedicated to Dr. Laurent Robert. An active and important board member in the early years of the project, who passed away in 2016. He has been sorely missed in the experimental mechanics community. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525. B. Blaysat is grateful to the French National Research Agency (ANR) and to the French government research program "Investissements d'Avenir" for their financial support (ICAReS project, N ANR-18-CE08-0028-01 & IDEX-ISITE initiative 16-IDEX-0001, CAP 20-25). S. N. Olufsen gratefully appreciate the financial support from the Research Council of Norway through the Centre for Advanced Structural Analysis, Project No. 237885 (SFI-CASA). B. Blaysat acknowledges useful discussions with M. Grédiac. Conflicts of Interest: Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by NIST, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.

Additional details

August 22, 2023
October 23, 2023