International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004
target is rejected from the sequence (see the abnormal position
and velocity vector in Fig. 9, at the bottom).
800
600 T - T. s “4200
Figure 9: 3D position and velocity vectors of the targets at
different times
In order to assess the repeatability of the test under identical
condition, the trajectories of target 79 (2nd column, middle) in
four test have been superimposed on the same graph (see Fig.
10 and 11).
Confronto dellaposizione in x nel tempo
1500 -
| prova del 04-09-03
1400 1 prova del 09-08-03
| prova del 28-09-03
| — prova del 29-09-03 de
1300 re ee re rs
1200
1100
= 1000 oA
= yt
900
800
700
600-
500
0 0.2 0.4 0.6 0.8 1 12 14 16
Figure 10: position of the target 79 at different times
It can be seen that the agreement is quite good, especially for
velocities (the differences in the final position are up to 20 cm,
this depends on a different height of the sand specimen in these
tests).
Pallino79
3000 ---- s :
prova del 04-07-03
prova del 09-07-03
2500 prova del 28-07-03
prova del 39-07-03
2000 -
r3 ,
E FR
E 1500: FEN
= N
> «
1000 X
s. / N
j
0 05 + 15 8 259 3 335 4 45
tempo (s)
Figure 10: position of the target 79 at different times
4. CONCLUSIONS
Overall, both cases were solved to a high degree of automation,
and with accuracy level that, perhaps of not-so-high quality in
the second case, but still more than enough for the application
at hand. Using a prediction model to label the target along the
sequence seems to be a feasible and flexible technique, but its
reliability with only two cameras and a low frame rate cannot
be guaranteed and demands additional efforts to control the
results.
References
Montrasio, L., and Nova, R., 1989. Assestamenti di una
fondazione modello sotto carico inclinato: risultati sperimentali
e modellazione matematica, Rivista Italiana di Geotecnica,
pp.35-49.
Hampel, U., and Maas, H.-G., 2003. Application of Digital
Photogrammetry for Measuring Deformation and Cracks during
Load Tests in Civil Engineering Material Testing. In Proc. of
Optical 3D Meas. Tech. VI, Zurich, pp. 80-88.
Gruen, A., 1985. Adaptive least squares correlation: a powerful
image matching tecnique. South African Journal of Photog.,
Remote Sensing and Cartography, 14(3), pp. 175-187.
Gruen, A., 1996. Least squares matching: a fundamental
measurement algorithm. In: K. Atkinson (ed.), Close Range
Photogrammetry & Machine Vision, Whittles, pp. 217-255.
Baltsavias, E.P., (1991). Geometrically Constrained Multiphoto
Matching. Mitteilungen No. 49, Inst. of Geodesy and
Photogrammetry, ETH, Zurich.
Gordon, S.J., Lichti, D.D., Chandler, I., Stewart, M.P., Franke,
J., 2003. Precision Measurement of Structural Deformation
using Terrestrial Laser Scanners. In Proc. of Optical 3D
Measurement Techniques VI , Zurich, pp. 322-329.
References from websites
www.cimne.upc.es, accessed at 1 May 2004.
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