50thAnniversary Article: Effect of Sensor Noise on the Resolution and Spatial Resolution of Displacement and Strain Maps Estimated with the Grid Method

摘要: This paper deals with noise propagation from camera sensor to displacement and strain maps when the grid method is employed estimate these quantities. It shown that closed-form equations can be predict link between metrological characteristics such as resolution spatial in on one hand various quantities characterising images brightness, contrast standard deviation of other hand. Various numerical simulations confirm first relevance this approach case an idealised impaired by a homoscedastic Gaussian white noise. Actual CCD or CMOS sensors exhibit, however, heteroscedastic A pre-processing step therefore proposed stabilise variance prior employing predictive equations, which provide due based both modelling use generalised Anscombe transform variance. Applying procedure translation test confirms it possible model correctly maps, thus also actual resolution, images.