Three-dimensional profilometry based on focus method by projecting LC grating pattern

摘要

This paper describes a 3D surface profile measurement based on focus method by an optical sectioning. The optical system is employed uniaxial condition of projection and observation axis. The contrast of projected sinusoidal pattern onto the sample is approximated the Gauss distribution along the distance. The highest contrast indicates at the focused plane. It is possible to analyze the contrast distribution by a grating projected method using a liquid crystal grating. A phase-shifting method is applied to the contrast analysis. The liquid crystal grating is powerful tool to make arbitrary intensity and frequency distribution. Surface profiles of mechanical parts were measured to demonstrate for this method.rnthree-dimensional shape measurement, focus method, contrast variation, optical sectioning, liquid