A new methodology is proposed to estimate displacement fields from pairs of images (reference and strained) that evaluates continuous displacement fields. This approach is specialized to a finite-element decomposition, therefore providing a natural interface with a numerical modeling of the mechanical behavior used for identification purposes. The method is illustrated with the analysis of Portevin-Le Châtelier bands in an aluminum alloy sample subjected to a tensile test. A significant progress with respect to classical digital image correlation techniques is observed in terms of spatial resolution and uncertainty.

The current state of the art of digital image correlation, where displacements can be determined for values less than one pixel, enables one to better characterise the behaviour of materials and the response of structures to external loads. A general presentation of the extraction of displacement fields from pictures taken at different instants during an experiment is given. Different strategies can be followed to determine subpixel displacements. New identification procedures are then devised making use of full‐field measurements. A priori or a posteriori routes can be followed. They are illustrated on the analysis of a Brazilian disk test.

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