Impact of X-ray CT calibration steps on DVC and P-DVC displacement uncertainties

X-ray tomography can be used to measure displacement fields from in situ or ex situ mechanical tests. The present work aims to quantify displacement uncertainties resulting from different reconstruction steps implemented in computed tomography. Two samples made of polyamide and aluminum alloy were imaged in situ by acquiring radiograph sets corresponding to two tomographic turns. From these data sets, the standard displacement uncertainties were assessed via digital volume correlation (DVC) and projection-based DVC (P-DVC). Careful calibration of the computed tomography geometry, accounting for beam hardening and correcting dark-and flat-field variations, was crucial to reach sub-decivoxel uncertainties.