Structured lighting method using moire pattern projection

Toru Yoshizawa; Takayoshi Yamaguchi; Hiroshi Takahashi; Naohito Ikeda; Masayuki Yamamoto; Shigeru Nagamori

doi:10.1117/12.455239

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11 February 2002 Structured lighting method using moire pattern projection

Toru Yoshizawa, Takayoshi Yamaguchi, Hiroshi Takahashi, Naohito Ikeda, Masayuki Yamamoto, Shigeru Nagamori

Author Affiliations +

Proceedings Volume 4567, Machine Vision and Three-Dimensional Imaging Systems for Inspection and Metrology II; (2002) https://doi.org/10.1117/12.455239
Event: Intelligent Systems and Advanced Manufacturing, 2001, Boston, MA, United States

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.

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Toru Yoshizawa, Takayoshi Yamaguchi, Hiroshi Takahashi, Naohito Ikeda, Masayuki Yamamoto, and Shigeru Nagamori "Structured lighting method using moire pattern projection", Proc. SPIE 4567, Machine Vision and Three-Dimensional Imaging Systems for Inspection and Metrology II, (11 February 2002); https://doi.org/10.1117/12.455239

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