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Title: Camera system resolution and its influence on digital image correlation

Digital image correlation (DIC) uses images from a camera and lens system to make quantitative measurements of the shape, displacement, and strain of test objects. This increasingly popular method has had little research on the influence of the imaging system resolution on the DIC results. This paper investigates the entire imaging system and studies how both the camera and lens resolution influence the DIC results as a function of the system Modulation Transfer Function (MTF). It will show that when making spatial resolution decisions (including speckle size) the resolution limiting component should be considered. A consequence of the loss of spatial resolution is that the DIC uncertainties will be increased. This is demonstrated using both synthetic and experimental images with varying resolution. The loss of image resolution and DIC accuracy can be compensated for by increasing the subset size, or better, by increasing the speckle size. The speckle-size and spatial resolution are now a function of the lens resolution rather than the more typical assumption of the pixel size. The study will demonstrate the tradeoffs associated with limited lens resolution.
Authors:
 [1] ;  [1] ;  [1] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
1114600
Report Number(s):
SAND--2013-8737J
Journal ID: ISSN 0014-4851; PII: 9886
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Experimental Mechanics
Additional Journal Information:
Journal Volume: 55; Journal Issue: 1; Related Information: Proposed for publication in Experimental Mechanics.; Journal ID: ISSN 0014-4851
Publisher:
Springer
Research Org:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION digital image correlation; uncertainty quantification; optical measurements; full-field measurement; lens resolution