Automatic fringe analysis for moiré topography

Abstract Two digital systems are developed for the automatic measurement of 3-D shapes using moire techniques—an automatic 3-D shape measuring system using the scanning moire method and an interactive fringe analysing system for moire fringe photographs. In the automatic 3-D shape measuring system, a deformed grating is scanned and sampled with an electronic image scanning device so that moire fringes are generated in a computer. This technique of electronic fringe generation eliminates ambiguity with regard to the sign of the moire fringes. The interactive fringe analyser provides a flexible and versatile tool for moire fringe analysis. Medical applications of these analysing systems are discussed.