Surface Profile Measaurement of Specular Objects by Grating Projection Mehtod (2nd Report)

Measurement of Ellipsoidal Mirror

Abstract

This paper describes a grating projection method for three-dimensional profile measurement of specular objects and the method is utilized to measure a concave-shaped mirror that is difficult to measure using conventional non-contact methods in short time. A "deformed grating pattern" is observed when the reference grating is projected onto a mirror-like surface. This pattern formed by the surface reflection is captured by a CCD camera and analyzed on the basis of phase shifting technique to give three-dimensional profile of the specimen. Experimental results are shown with respect to an ellipsoidal mirror to verify the principle proposed here.