When three-dimensional measurements are conducted with fringe projection, the quality of the grating used for the generation of the fringes is important. It has a direct influence on the achievable depth resolution in a given measurement setup. In the past, Ronchi gratings or gratings written in nematic liquid-crystal displays or in digital micromirror devices have been used. We report on the application of a reflective ferroelectric liquid-crystal-on-silicon display as the fringe-generating element in a setup based on a stereo microscope. With this device the depth resolution of measurements by use of phase-shifting algorithms can be significantly improved compared with the application of a Ronchi grating or a nematic liquid-crystal display.
© 2003 Optical Society of America
[Optical Society of America ]
(120.6650) Instrumentation, measurement, and metrology : Surface measurements, figure
(150.6910) Machine vision : Three-dimensional sensing
(230.3720) Optical devices : Liquid-crystal devices
Klaus-Peter Proll, Jean-Marc Nivet, Klaus Körner, and Hans J. Tiziani, "Microscopic three-dimensional topometry with ferroelectric liquid-crystal-on-silicon displays," Appl. Opt. 42, 1773-1778 (2003)