Contouring reflective plates through image resizing and Iterative Intensity Integration Technique (IIIT)

Abstract

Iterative Intensity Integration Technique (IIIT) is an intensity based correlation technique used to obtain the slope and curvature of loaded reflecting plates. Energy conservation principle forms the basis for this technique. The total quantity of light reflected by specimen before and after loading is assumed to be identical. It is best suited for contouring reflective plates that produce constant image size in load and unload state. But the corner and simply supported plates having the free edges to rotate while loading make reflected image enlarge/shrinks. Hence, preprocessing one of the images is mandatory to make it equal to size of other. In this present study, reflecting plates of corner supported rhombus and rectangular plate with holes are chosen and the experiments are conducted for central loading. One of images is resized and those images are subjected to IIIT. A suitable correction procedure is applied to results obtained from IIIT to get the final result. The same plates are modelled using ANSYS for known displacement and the partial slope and curvature values are determined. The obtained ANSYS results are exported to MATLAB for comparison of results with experiments and the least square errors are presented.