Modal Pursuit to detect large displacements and strain fields by Digital Image Comparison

Digital Image Correlation offers a useful approach to resolve displacements and strains by picture comparisons. However, many of the several methods proposed in the past suffer the occurrence of large displacements between the two compared pictures. The Modal Pursuit approach here introduced intends to give a possible strategy to prevent this limitation. The main advantage is that the method uses a global approach for the solution strategy. The solution approach uses a displacement basis that derive from a modal analysis on a membrane structure whose shape is the same than the image under investigation. The modes are introduced a little at a time so that the procedure is facilitated to converge, even when only two pictures (undeformed and final state) are used for the matching.