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Proceedings Paper

Three-dimensional imaging using liquid crystal grating projection
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Paper Abstract

This paper describes a device for 3D profile measurement systems which are based on grating projection method using phase shifting technique. As a key component to these systems, we propose to apply a liquid crystal (LC) grating instead of a conventional ruled grating which has difficulty in speedy and accurate shifting of the projected pattern. This LC grating consists of 960 lines of stripe pattern on the substrate of 60×40 mm2 in size and has such features as 8 bits of gray levels in dynamic range in mono-chromatic usage. A sinusoidal pattern as well as a binary pattern is realized by combining pulse width modulation control (PWMC) and frame ratio control (FRC) technique. The period of the pattern is arbitrarily controlled and, in addition, shifting of the projected pattern is also electrically realized. We demonstrate a few examples measured by the system which has this LC grating built in.

Paper Details

Date Published: 23 October 2003
PDF: 8 pages
Proc. SPIE 5202, Optical Information Systems, (23 October 2003); doi: 10.1117/12.505287
Show Author Affiliations
Toru Yoshizawa, Tokyo Univ. of Agriculture and Technology (Japan)
Hiroo Fujita, Citizen Active Co., Ltd. (Japan)
Yukitoshi Otani, Tokyo Univ. of Agriculture and Technology (Japan)
Masayuki Yamamoto, Softron Corp. (Japan)

Published in SPIE Proceedings Vol. 5202:
Optical Information Systems
Bahram Javidi; Demetri Psaltis, Editor(s)

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