Closed-Loop Optimization of DIC Speckle Patterns Based on Simulated Experiments

Stereo digital image correlation (DIC) spreads widely in the last years as one of the most flexible and accurate full-field displacement-strain measurement techniques. The development of novel applications based on DIC makes the design of 3-D setups a challenging task, given the complex and nonlinear nature of stereophotogrammetric methods. The present literature allows the design and optimization of DIC experimental setup only with approximated uncertainty models or upon image quality metrics that are linked loosely with the actual value of uncertainty. In this paper, a closed-loop optimization method based on 3-D experiment simulation is presented. The approach may be used to optimize several parameters (from the camera setup to the DIC processing parameters). This paper features a case study on the problem of optimizing a regular speckle pattern for different measurement tasks. The whole approach is validated experimentally in Section V.