Digital image correlation method with differential evolution

A new intelligent digital image correlation (DIC) method that uses differential evolution is presented, which can accurately measure the surface displacements and strains of the deformed object, even which has a rigid body rotation with arbitrary angle. The rotation angle is contained in the correlation function considering the influence of rigid body rotation of the interrogated subset. Due to the extraordinary ability of global optimum of differential evolution, the proposed method can complete reliable and accurate correlation-matching searching in the deformed image. Then the search results are employed as the initial guess of Newton-Rapshon (N-R) method to further improve the registration accuracy. The proposed method overcomes the shortcoming of the general digital image correlation method, which can work under the condition that the tested object has a rotation angle larger than seven degree.