Two-Wavelength Phase-Shifting Projection $Moir\acute{e}$ Topography for Measurement of Three-Dimensional Profiles with High Step Discontinuities

Abstract

[] technique is now being extensively investigated as a fast non-contact means of three-dimensional profile measurement especially for reverse engineering. One problem with technique is so called -ambiguity problem that limits the maximum step height difference between two neighboring sampling points to be less than half the equivalent wavelength of fringes. In this investigation, a new two-wavelength scheme of projection topography is proposed and tested to cope with the -ambiguity problem. Experimental results are discussed to assess the new method in measuring large objects with high step discontinuities.