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A digital image correlation procedure is developed to perform kinematic measurements on the surface of 316LN austenitic steel polycrystals. A sequence of images is acquired using a Scanning Electron Microscope (SEM) during in situ tensile tests for various mean grain sizes. To enable digital image correlation, a speckle pattern adapted to the microscopic scale is deposited onto the specimen surface by microlithography. The knowledge of the microstructure at the surface allows for kinematic measurements to be performed using an unstructured finite element mesh consistent with the grain boundaries. The same mesh is then used for the simulation of each tensile test on the experimental microstructure with the measured nodal displacements prescribed as boundary conditions. A crystal plasticity law is considered to simulate the observed strain heterogeneities. An inverse identification method is …