High-Precision Moiré Topography Based on Scanning Techniques

Abstract

The ease of measuring diffuse surfaces has been significantly increased by the development of moiré topographic techniques [1]. Recently, we reported a promising automatic 3-D shape measuring method, called the scanning moiré method [2]. In this method, moiré fringes are generated by the electronic scanning and sampling of a deformed shadow grating, instead of superposition of a reference grating in the conventional moiré topography. The electronic scanning and sampling technique automatically eliminates the shape ambiguity problem, which is serious in the conventional moiré topography. A practical measuring system has been developed [3], especially for medical applications. An optical system of a moiré camera for medical application is used, and data from the photodiode array are processed by a microcomputer.