The digital image correlation (DIC) method has been well recognized as a simple, accurate and efficient method for mechanical behavior evaluation. However, very few researches have concentrated on the relationship between the characteristics of the camera lens and the measurement error of the DIC method. The modulation transfer function (MTF) has commonly used for evaluation of the resolution capability of camera lens. In practice, when the DIC method is used, it is possible that the captured images become too blur to analyze when the object is out of the focus of the camera lens or the object deviates from the line-of-view of the camera. In this paper, the traditional MTF calibration specimen was replaced by a pre-arranged speckle pattern on the specimen. For DIC images grabbed from several selected locations both approaching and departing from the focus of the camera lens, corresponding MTF curves were obtained from the pre-arranged speckle pattern. The displacement measurement errors of the DIC method were then estimated by those obtained MTF curves.

Date Published: 22 June 2013
PDF: 10 pages
Proc. SPIE 8769, International Conference on Optics in Precision Engineering and Nanotechnology (icOPEN2013), 876910 (22 June 2013); doi: 10.1117/12.2021045

Published in SPIE Proceedings Vol. 8769:
International Conference on Optics in Precision Engineering and Nanotechnology (icOPEN2013)
Chenggen Quan; Kemao Qian; Anand Asundi, Editor(s)