the approach proposed to do the measurements of the
discharge, based on the 3D-snake. As an example,
was obtained for the discharge lenghts: ≈ (60.46 ±
0.44)mm. The set of dischargespresents very low cur-
vature, so the distance d
AB
≈ (60 ± 0.5)mm shown in
(Fig. 12) is a good result for the true length, allowing
characterization of the electrical discharges, such as
current density and other electrical parameters.
After these experiments the method will be ap-
plied to high voltage transmission lines.
6 CONCLUSIONS
This work described and validated an approach to be
applied in modelling of electrical discharges captured
in a sequence of stereo pairs. The approach was tested
with an image database built by a consistent strategy
and the cameras were based on the classical theoreti-
cal pinhole camera model.
The results obtained by 3D-snake in estimating
the length of the curves are coherent with the real
lengths. Since the cameras are calibrated it is also
possible to determinate the real position of the electri-
cal discharge during the time of the image acquisition,
so the approach proposed here can work as a strategy
for tracking. A new ﬁeld of application for 3D active
contours is opened, such as the tracking of electrical
discharges captured in a pair of digital videos and the
study of fast events.
Thus, in the near future this methodology will
be applied in the studies of real electrical discharges
where, certainly, will be found new constraints and
more critical requirements to be evaluated.
ACKNOWLEDGEMENTS
The authors thank the ﬁnancial support received from
FAPESP - The State of S˜ao Paulo Research, from
CNPq - The National Council for Scientiﬁc and Tech-
nological Development and from CAPES - Coordina-
tion of Improvement of Higher Level Education Per-
sonnel. Special thanks to Mr. Marco Iacovacci.
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