Experimental implementation of visual cryptography based on time average moiré

Geometric moiré is a classical in-plane whole-field non-destructive optical experimental techniquebased on analysis of visual patterns produced by superposition of two regular gratings that geometrically interfere.Two basic goals exist in moiré pattern research.The first is the analysis of moiré patterns.The task is to analyze and characterize the distribution of moiré fringes in a moiré pattern.Most of the research in moiré pattern analysis deals with the interpretation of experimentally produced patterns of fringes and determination of displacements (or strains) at centerlines of appropriate moiré fringes.Another goal is moiré pattern synthesis when the generation of a certain predefined moiré pattern is required.The synthesis process involves production of such two images that the required moiré pattern emerges when those images are superimposed.Moiré synthesis and analysis are tightly linked and understanding one task gives insight into the other.