This abstract briefly describes a novel continuum finite strain formulation of the equilibrium gap principle, introduced in (CLAIRE, HILD et ROUX, 2004) at the discrete level for linearized elasticity, used as a regularizer for finite element-based image correlation problems. Consistent linearization and finite element discretization is provided. The method is implemented using FEniCS & VTK, in a freely available python library. The equilibrium gap constraint regularizes the image correlation problem, even in presence of noise, and without affecting strain measurement.