Department of Mechanical Engineering, Campus Científico Tecnológico de Linares, University of Jaén, 23700 Linares, Spain.
Department of Mechanical and Mining Engineering, Campus Las Lagunillas, University of Jaén, 23071 Jaén, Spain.
Sensors (Basel). 2018 Sep 17;18(9):3130. doi: 10.3390/s18093130.
Three-dimensional digital image correlation (3D-DIC) has become the most popular full-field optical technique for measuring 3D shapes and displacements in experimental mechanics. The integration of fringe projection (FP) and two-dimensional digital image correlation (FP + DIC) has been recently established as an intelligent low-cost alternative to 3D-DIC, overcoming the drawbacks of a stereoscopic system. Its experimentation is based on the colour encoding of the characterized fringe and speckle patterns required for FP and DIC implementation, respectively. In the present work, innovations in experimentation using FP + DIC for more accurate results are presented. Specifically, they are based on the improvement of the colour pattern encoding. To achieve this, in this work, a multisensor camera and/or laser structural illumination were employed. Both alternatives are analysed and evaluated. Results show that improvements both in three-dimensional and in-plane displacement are obtained with the proposed alternatives. Nonetheless, multisensor high-speed cameras are uncommon, and laser structural illumination is established as an important improvement when low uncertainty is required for 2D-displacement measurement. Hence, the uncertainty has been demonstrated to be reduced by up to 50% compared with results obtained in previous experimental approaches of FP + DIC.
三维数字图像相关（3D-DIC）已经成为实验力学中测量三维形状和位移的最流行的全场光学技术。最近，条纹投影（FP）和二维数字图像相关（FP+DIC）的集成已经作为一种智能的低成本替代 3D-DIC 方法建立起来，克服了立体系统的缺点。它的实验是基于特征条纹和散斑模式的颜色编码，分别用于 FP 和 DIC 的实现。在本工作中，提出了使用 FP+DIC 进行更精确结果的实验创新。具体来说，它们基于对颜色图案编码的改进。为了实现这一目标，在这项工作中，使用了多传感器相机和/或激光结构照明。这两种替代方案都进行了分析和评估。结果表明，所提出的替代方案在三维和平面位移方面都有了改进。尽管如此，多传感器高速相机并不常见，而激光结构照明在需要 2D 位移测量的低不确定性时，被确立为一个重要的改进。因此，与以前的 FP+DIC 实验方法相比，不确定性已被证明降低了多达 50%。
