Abstract

In the production of moire fringes by the obstruction theory, the relationship between the light source and a single Ronchi ruling is observed. A uniform extended light source is imaged by a TV camera with the insertion of a grating between light source and camera. The image of the light source overlaps the projection of the grating. When the grating moves away from the light source, the image pattern varies periodically with the change in distance between light source and grating. The effect can be explained with geometric optics imaging theory combined with the geometric projection principle of the point source to an obstructing object.

© 1989 Optical Society of America