Influence of the sampling density on the noise level in displacement and strain maps obtained by processing periodic patterns

International audienceThe aim of this study is to investigate the influence of the sampling density of periodic patterns such as checkerboards or 2D grids on the noise level observed in displacement and strain maps extracted from such images. A spectral method named Localized Spectrum Analysis (LSA) is used to process the images. It is shown that this parameter influences this noise level. This influence is quantified, and a power law is proposed to model it, with a value of the power identified with the measurements. It is also confirmed that checkerboards give a lower noise level than 2D grids, with an improvement which is also quantified, and which increases as the sampling density increases