15 February 1993 Displacement measurement by the detection of contrast variation of a projected pattern
Author Affiliations +
Proceedings Volume 1756, Interferometry: Applications; (1993); doi: 10.1117/12.140789
Event: San Diego '92, 1992, San Diego, CA, United States
A system has been developed and tested for optical noncontact measurement of displacement. The system consists of a light source, an objective lens, a quadrant pattern and a quadrant photodiode. The principle is based on the detection of the contrast variation of the projected quadrant pattern as a function of defocus. This system has coaxial projection and observation axes and is hardly influenced by the color and inclination of the surface. The direction of displacement can be identified by using one pair of detectors. Experimental tests verify the principle of the method and some tests of the system in applications are tried with expected results.
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Toru Yoshizawa, Yukitoshi Otani, Akiyoshi Tochigi, Tsutomu Furuki, "Displacement measurement by the detection of contrast variation of a projected pattern", Proc. SPIE 1756, Interferometry: Applications, (15 February 1993); doi: 10.1117/12.140789; https://doi.org/10.1117/12.140789

Signal detection



Light sources

Optical testing


Signal processing

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