MEASURING SURFACE FLATNESS USING SHADOW MOIRE TECHNOLOGY AND PHASE-STEPPING IMAGE PROCESSING

摘要

A system for quantifying the surface flatness of objects utilizing shadow moire and phase-stepping image processing techniques. A grating (28) is suspended above an object and illuminated by a light source (32). The light source projects a shadow of opaque lines upon the object. A two-dimensional array of phase values is calculated from digitized phase-shifted shadow moire fringe patterns that are indicative of the flatness of the surface of an object (22). There may be three, four or more of such phase shifted shadow moire fringe patterns.