Progress in digital image correlation method

Photomechanics Laboratory in the University of Science and Technology of China has concentrated on principles and applications of digital image correlation (DIC) recent years. Photomechanics Laboratory not only has improved the accuracy and efficiency of DIC but also has achieved research findings on speckle pattern standardization, compensation method for 2D DIC, biomedical engineering, and serrated yielding phenomenon. This paper provides a review: (1) a theoretical model and an estimation algorithm were presented for shape function error in local deformations, and a subset size chosen criterion was presented to ensure the measurement performance; inverse compositional Gauss-Newton method using second order shape function was presented, which is two-times faster than the traditional method. (2) The inherent nature of interpolation bias was revealed, an experimental approach was developed to measure the interpolation bias, a speckle pattern assessment that considering the effects of both the systematic error and random error was presented, and a theoretical model for the speckle pattern optimization was built. (3) Compensation methods for 2D DIC based on pre-calibration were presented. (4) A system for orthognathic surgery navigation was built; full-field pulse vibration measurement system was developed. (5) The emergence and evolution of PLC band was observed, and the phenomenon of out-of-band shrink is found. The strain localization in the width-wise direction was observed using two 2D DIC systems. (6) The vibration and strain were dynamically measurement using the speckle correlation method.