Separation of Additive and Subtractive Moiré Patterns

Abstract

Using a spatial filtering technique, moiré patterns can be observed that correspond to different forms of the indicial equation describing the parametric properties of gratings and moiré. In particular both the additive and subtractive moirés are obtained individually over the field. This method, combined with a previously developed method for obtaining spatial partial derivatives from deformed gratings, permits the experimental determination of the whole field of Cartesian shears and rigid rotations.