Moire deflectometry is capable of accurately measuring various properties of reflective surfaces. The basic quantity derived from fringe shifts is a map of surface slopes in a given direction. When surface variations are small and rapid, such as on a rough surface, the Imperfections are evident as fringe contrast reduction rather than fringe distortions. The roughness parameters are obtained from the dependence of the contrast on deflectometer sensitivity. The fringe visibility vs. sensitivity curve is a scaled version of the surface autocovariance. The autocovariance function allows quantitative evaluation of average surface heights, RMS, slope RMS, periodicities, and other features which determine the surface quality. The method is demonstrated on a diamond turned hard disk with concentric circular periodic grooves. The surface period and direction is derived from the autocovariance.

Date Published: 1 April 1991
PDF: 9 pages
Proc. SPIE 1442, 7th Mtg in Israel on Optical Engineering, (1 April 1991); doi: 10.1117/12.49069

Published in SPIE Proceedings Vol. 1442:
7th Mtg in Israel on Optical Engineering
Moshe Oron; Itzhak Shladov, Editor(s)