To create a hybrid system applied to mechanical structure analysis link to experimental optical techniques (EOTs) and computer modeling (CM), the correlation problem between CM and EOT methods must be solved. A mapping correlation algorithm (MCA) is proposed as the interface between both techniques. Out-of-plane electronic speckle pattern interferometry (ESPI) as the experimental optical technique and a commercial finite element method (FEM) package are employed. The MCA proposed is based on a set of mapping functions, which are found by least-squares algorithms and enable the compensation of image distortions produced by the experimental optical setup. The algorithm was tested initially on a simple 2-D structure and two 3-D complex mechanical structures. Results are reported. Further, the MCA algorithm linking ESPI-FEM methods is applied to out-of-plane displacements over a rectangular plate under stress. Numerical and experimental results along with their error analysis are also presented.