By construction digital image correlation is an ill-posed problem. To circumvent this di culty, the regularization is often performed implicitly through the kinematic basis chosen to express the sought displacement fields. Conversely, a priori information on the mechanical behavior of the studied material is often available. It is proposed to evaluate the gain to be expected from such a mechanical assistance, namely, the measured displacement not only satis es as best as possible the gray level conservation, but also mechanical admissibility.