Short remarks about synthetic image generation in the context of sub-pixel accuracy of Digital Image Correlation

International audience
In order to characterise the ultimate error regime of Digital Image Correlation (DIC) algorithms, sets of virtual transformed images are often generated from a reference image by in-plane sub-pixel translations. This leads to the determination of the well-known S-shaped systematic error curves and their corresponding random error curves. It is reported in this collaborative work that the a priori choices used to numerically shift images (grey level interpolation, direct or reverse transformation between images) modify DIC results and may lead to biased conclusions in terms of DIC errors.