Principle of Digital Image Correlation

Digital image correlation (often referred to as “DIC”) is an easy-to-use, non-contact optical method which measures deformation on the surface of an object. This method tracks the displacements in the speckle pattern in small neighborhoods called subsets (indicated in red in the figure below) during deformation. Digital image correlation has repeatedly proven to be accurate when compared to LVDTs, strain gauges, and valid FEA models for many years. It is now the industry-leading optical measurement method around the world. The DIC systems from Correlated Solutions utilize the most advanced hardware available to ensure the system is fast, robust, and produces the most accurate data.

For a comprehensive introduction to digital image correlation technology, watch the guest lecture by Alistair Tofts linked below. As part of the Oregon State University College of Engineering's seminar series, Alistair and OSU engineering professor Dr. Brian Bay discuss specific application examples that highlight the potential for this technology.

We wrote the book.

Co-authored by the founders of Correlated Solutions, Image Correlation for Shape, Motion and Deformation Measurements: Basic Concepts, Theory and Application is a comprehensive overview of data extraction through image analysis. The book is a collaboration of decades of research and development of 2D and 3D digital image correlation software, which have been implemented into our products. The book can be purchased from many online retailers or directly from Correlated Solutions.

Here are just a few of the hundreds of academic publications associated with Correlated Solutions and its founders.

Systematic errors in digital image correlation caused by intensity interpolation. Schreier, H.W., Braasch J.R., & Sutton, M.A. Optical Engineering (2000) 39(11): 2915.

Full-field speckle pattern image correlation with B-spline deformation function. Cheng, P., McNeill, S.R., Schreier, H.W., & Sutton, M.A. Experimental Mechanics (2002) 42: 344.

Systematic errors in digital image correlation due to undermatched subset shape functions. Schreier, H.W., & Sutton, M.A. Experimental Mechanics (2002) 42: 303.

Advances in light microscope stereo vision. Schreier, H.W., Garcia, D., & Sutton, M.A. Experimental Mechanics (2004) 44: 278.

Scanning electron microscopy for quantitative small and large deformation measurements. Sutton, M.A., Li, N., Garcia, D., Cornille, N., McNeill, S.R., Schreier, H.W., & Orteu, J.J. Experimental Mechanics (2006) 47(6): 789.

The effect of out-of-plane motion on 2D and 3D digital image correlation measurements. Sutton, M.A., Yan J.H., Tiwari, V, Schreier, H.W., & Orteu, J.J. Optics and Lasers in Engineering (2008) 46(10): 746.

Mixed-mode crack growth in ductile thin-sheet materials under combined in-plane and out-of-plane loading. Yan, JH., Deng, X., Wei, Z. Zavattieri, P., & Sutton, M.A. International Journal of Fracture (2009) 160: 169.

A collaborative effort from industry professionals including the founders of Correlated Solutions, A Good Practices Guide for DIC provides guidelines for conducting DIC measurements in conjunction with mechanical testing of a planar test piece. This guide is designed to be both a primer training document geared towards new practitioners of DIC (supplementing vendor-based or other formal training and hardware and software-specific documentation) as well as a reference for experienced users, to refresh their fundamentals knowledge and skill sets and assist them in troubleshooting DIC measurements. The Good Practices Guide focuses on good practices for DIC measurement setup, image correlation, and basic post-processing of DIC data for strain computations.