Characterizing the measurement resolution and measurement bias of Sampling Moiré

Sampling moiré is a spatial fringe pattern analysis method which can be used to retrieve displacement fields on the surface of deformed specimens marked by a periodic pattern. We prove that, under mild assumptions, Sampling Moiré (SM) is equivalent to another full-field method, namely the Localized Spectrum Analysis (LSA). The prospects opened up by this result concern two metrological indicators, namely the measurement bias (the retrieved displacement being affected by a systematic error) and the measurement resolution (limited by the propagation of sensor noise to displacement maps). Previous studies on LSA yield predictive formulas for measurement bias and displacement resolution. These formulas are adapted here to the case of SM. Relevant numerical studies enable us to assess to what extent those predictive formulas are satisfied, interpolation performed in SM and not in LSA affecting the quality of the final result.