Virtual Image Correlation uncertainty

M.L.M. François (1)

1 GeM - Institut de Recherche en Génie Civil et Mécanique

The Virtual Image Correlation method applies for the measurement of silhouettes boundaries with sub-pixel uncertainty. It consists in a correlation between an image of interest and a virtual image based on a parametrized curve. It is shown that the method is exact in 1D, insensitive to contrast variation, and that the bias induced by brightness variation can be easily corrected. Optimal value of the virtual image width, the sole parameter of the method, and optimal numerical settings are established. An estimator is proposed to assess the relevance of the user-chosen parametrized curve family to match the contour. An analytical formula and a diagram are given for the measurement uncertainty in both cases of noiseless and noisy images. The results obtained are validated by tests carried out on synthetic images and on real images.

Mots clés: Virtual Image Correlation

Domaines: Vision par ordinateur et reconnaissance de formes [cs.CV]; Imagerie médicale

M.L.M. François. Virtual Image Correlation uncertainty. International Journal for Numerical Methods in Engineering, 2022, 123 (18), ⟨10.1002/nme.7037⟩. ⟨hal-02933815v1⟩