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IBRACON Structures and Materials Journal • 2013 • vol. 6 • nº 3
A. P. Martins | J. C. Pizolato Junior | V. L. Belini
Figure 14 – Repeatability error comparison
between the proposed method and the
pachymeter conventional method, in relation
to the crack opening physical dimensions
by means of an image processing algorithm in a mobile platform.
The comparative experiments were accomplished between the vi-
sion system proposed and the conventional crack opening mea-
suring method. In the comparing, it was used the compression test
on specimen, for the faster acquisition of different cracks dimen-
sions. The results demonstrated that the proposed dimensional
crack monitoring method overcame in various aspects the conven-
tional technique. The vision system presented in this work, which
uses a mobile phone for the image acquisition and processing,
produced the following results:
n
Smaller subjectivity on the identification of alterations on the crack
region, without depend of the technician’s experience on reading
and interpreting procedures of the metrology instruments;
n
More accurate and reliable results, regardless the index of the
cracks found and of the observed crack opening dimensions;
n
The percentual index of the cracks area is obtained directly on
the mobile phone’s screen as the images are captured and pro-
cessed, differently of the conventional method that demands
exhaustive measuring and off-line calculations to achieve the
results;
n
The shorter measuring time, constant and independent of the
length, form and index of crack found, represented other attrac-
tive results;
n
With the proposed method is possible to share the data obtained
on the cracks monitoring by means of mobile communication.
The use of a mobile phone with the support base offers repeatability
on the positioning of the proposed method in the crack area analy-
sis. An advantage of the support portable base (light and small) is
the mobility, especially interesting when different analysis must be
conducted on different environment with masonry structures.
The cracks monitoring on this present work may also be ap-
plied on the analysis of the behavior of different concrete com-
posts submitted to mechanical trials, with a crack evolution
observation.
7. Acknowledgements
The authors would like to thank the Department of Electrical En-
gineering of both the State University of Londrina (UEL) and the
Federal University of São Carlos (UFSCar) for their technical
support for conducting the present research and experiments.
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