Methodology for metrological analysis of periodic coding images: measurement resolution and spatial resolution

GDR CNRS 2519, « Mesure de champs et identification en mécanique des solides »

Abstract

Optical full-field techniques have a great importance in modern experimental mechanics. Even if they are reasonably spread among the university laboratories, their diffusion in industrial companies remains very weak for several reasons, especially a lack of metrological performance assessment. A full-field measurement can be characterized by its resolution, bias, measuring range, and by a specific quantity, the spatial resolution. The present communication proposes an original procedure for the estimation in one single step of the resolution, bias and spatial resolution for a given operator (decoding algorithm, such as image correlation, low-pass filters, derivation tools, ...). This procedure is based on the construction of a particular multi-frequential field, and a Bode diagram representation of the results. This analysis is applied to various phase demodulating algorithms for the estimation of in-plane displacements.