Three-dimensional optical topometry of technical surfaces becomes increasingly important for the control of industrial processes. However, the local reflectance of the surface of the investigated sample often varies within a wide range, making accurate measurements by fringe projection difficult. We demonstrate the use of a liquid-crystal spatial light modulator as the fringe-generating element in a standard stereo microscope. With this device the brightness of the projected patterns can be adapted pixelwise. This technique leads to a significant improvement of the results of our measurements with a phase-shifting algorithm.
© 2000 Optical Society of America
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(120.3940) Instrumentation, measurement, and metrology : Metrology
(180.6900) Microscopy : Three-dimensional microscopy
Klaus-Peter Proll, Jean-Marc Nivet, Christoph Voland, and Hans J. Tiziani, "Application of a liquid-crystal spatial light modulator for brightness adaptation in microscopic topometry," Appl. Opt. 39, 6430-6435 (2000)