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Proceedings Paper

Development of a non-contacting extensometer using digital speckle correlation
Author(s): Ichirou Yamaguchi; Koichi Kobayashi; Takashi Ida; Masayuki Yokota
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Paper Abstract

A new extensometer has been developed which needs no attachment of line markers or mechanical attachment on a specimen. An expanded beam from a laser diode is incident on the marker position of a specimen which is imaged by a lens on a C-MOS image sensor. The resultant laser-speckle patterns are analyzed by two-dimensional digital correlation at the rate of 20 frames per second. It provides speckle displacement by means of a phase-only-correlation device which uses only phase of Fourier transform of the image. In-plane displacement of the marker position is tracked by moving a head containing the laser and the image sensor under the feedback control that compensates for the speckle displacement detected. Two positions on the specimen are tracked by a pair of the heads. From rubber specimens which had a marker distance of 20 mm and were elongated at the velocity of 500 mm/sec we observed good agreement in load-strain curves with the results from the conventional methods using mechanical trackers.

Paper Details

Date Published: 18 August 2005
PDF: 10 pages
Proc. SPIE 5880, Optical Diagnostics, 58800E (18 August 2005); doi: 10.1117/12.618290
Show Author Affiliations
Ichirou Yamaguchi, Gunma Univ. (Japan)
Koichi Kobayashi, Toyo Seiki Seisaku-Sho, Ltd. (Japan)
Takashi Ida, Gunma Univ. (Japan)
Masayuki Yokota, Gunma Univ. (Japan)


Published in SPIE Proceedings Vol. 5880:
Optical Diagnostics
Leonard M. Hanssen; Patrick V. Farrell, Editor(s)

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