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Proceedings Paper

Structured lighting method using moire pattern projection
Author(s): Toru Yoshizawa; Takayoshi Yamaguchi; Hiroshi Takahashi; Naohito Ikeda; Masayuki Yamamoto; Shigeru Nagamori
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Paper Abstract

This paper describes a structured lighting method for the measurement of surface profiles of mat objects. In this kind of profilometry, a grating with binary transmittance distribution has been utilized. In these cases such a problem is known that an error is caused due to the non- sinusoidal transmittance of the grating. Another practical difficulty is in mechanical shifting of the grating. Here we propose to use a hybrid grating which consists of a conventional binary grating and a liquid crystal (LC) binary grating. Moire pattern produced by superposing these two binary gratings is available to overcome these problems. When two binary gratings are overlapped, the resultant moire pattern becomes closely sinusoidal in intensity distribution. And, when the LC grating pattern is moved, the projected pattern can be shifted arbitrarily in phase. Surface profiles of some samples are measured to show validity of hybrid grating projection and utility of the prototype system.

Paper Details

Date Published: 11 February 2002
PDF: 8 pages
Proc. SPIE 4567, Machine Vision and Three-Dimensional Imaging Systems for Inspection and Metrology II, (11 February 2002); doi: 10.1117/12.455239
Show Author Affiliations
Toru Yoshizawa, Tokyo Univ. of Agriculture and Technology (Japan)
Takayoshi Yamaguchi, Tokyo Univ. of Agriculture and Technology (Japan)
Hiroshi Takahashi, Tokyo Univ. of Agriculture and Technology (Japan)
Naohito Ikeda, Tokyo Univ. of Agriculture and Technology (Japan)
Masayuki Yamamoto, Tokyo Univ. of Agriculture and Technology (Japan)
Shigeru Nagamori, Mitsui Engineering and Shipbuilding Co., Ltd. (Japan)


Published in SPIE Proceedings Vol. 4567:
Machine Vision and Three-Dimensional Imaging Systems for Inspection and Metrology II
Kevin G. Harding; John W. V. Miller, Editor(s)

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