Simultaneous in-and-out-of-plane displacement measurements using fringe projection and digital image correlation

The combination of fringe projection (FP) and two-dimensional digital image correlation (2D–DIC) has been proposed in previous work [1] as an alternative method to obtain displacement maps in the three spatial directions. However, if a telecentric lens is not employed in the experimental setup, the in-plane displacements obtained with 2D–DIC are influenced by the out-of-plane displacements occurring during deformation. Nevertheless, this error can be corrected if the out-of-plane displacements are known, for instance from measurements using the FP technique. In this paper a novel methodology based on the combination of FP and 2D–DIC is employed to perform the correction of the in-plane displacements, and is applied to several experimental examples. Results are compared and validated with those obtained using a commercial 3D–DIC system showing an average displacement error of 4% for X-displacements and 6.5% for Y-displacements. •Optical analysis of the 3D displacements field occurring on an element during deformation.•3D displacement field obtained combining Fringe projection and 2D digital image correlation.•Both techniques run at the same time using on single RGB camera in combination with color encoding techniques.•A novel in-plane displacements correction using out-of-plane displacements is developed.•The combination of both techniques is successfully tested and results are compared with those obtained with 3D digital image correlation.