18 August 2005 Development of a non-contacting extensometer using digital speckle correlation
Author Affiliations +
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.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ichirou Yamaguchi, Ichirou Yamaguchi, Koichi Kobayashi, Koichi Kobayashi, Takashi Ida, Takashi Ida, Masayuki Yokota, Masayuki Yokota, "Development of a non-contacting extensometer using digital speckle correlation", Proc. SPIE 5880, Optical Diagnostics, 58800E (18 August 2005); doi: 10.1117/12.618290; https://doi.org/10.1117/12.618290


Back to Top