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Accuracy at 95% (m) Parallax RMS Max.
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Quadratic comp. 0,018
Av. quadratic 0,008
error
Average error 0,007
Maximun error 0,022 2,150
Table 1. Results obtained processing the data with a digital
photogrametric station “Photomodeler Pro 4.0”
3.2 Graphical results
The graphical results are shown by the flat representation of the
restored model and the projections of the three-dimensional
models with photorealistic textures.
In Figure 3, an elevation and a profile obtained from three-
dimensional points model , lines and polylines are shown,
which are restored on the digital photogrametric station
“Photomodeler Pro 4.0”. Later, the three-dimensional models
were transferred and processed on CAD software.
LITITI
Iit
4
B H
A
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Figure 3. Elevation and profile of the studied structure.
Different renderings of photo-realistic textures have been
obtained from the three-dimensional surface model, such as
those seen in Figure 4. These textures have been applied from
photographic shots of the object itself.
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004
Figure 4. Rendering with photo-realistic textures
4. CONCLUSIONS
The precision obtained in the process of generating three-
dimensional models, correspond perfectly with those expected
when applying simple photogrammetry principles of close
objects. The values and obtained precisions are agreed with the
demands of precision that are considered necessary between 2
and 5 cm (Scherer, 2002).
In regard to field work, it is highly important to make a good
initial planning because this will reduce the total amount of time
needed to optimize the results. A sketch of the object, the
position of both the plumb lines and the camera as well as the
field covered by each shot is fundamental in order to facilitate
later classification and processing work of the information
collected during this phase.
A fundamental part of the work which will determine the final
results quality will be the photographic shots taken and the
principles of photography and photogrammetry followed.
The use of digital cameras is considered ideal in situations in
which there is a limited budget to purchase equipment and
when the obtaining of high precisions is not essential.
Furthermore, this type of camera suitable because the cost of
developing the photos is practically null. Therefore it is
recommended to take many shots (from different positions and
view points), a factor which will directly influence the degree of
precision reached.
The use of digital monoscopic systems are recommended, also
denominated digital monoscopic photogrametric systems, to
process both data and also to obtain 3D models of the studied
structures. The fundamental motives will be due to the reduced
cost of the above (approximately 1200 €), as long as the
purchase of vision stereoscopic systems is not necessary.
However if necessary and due to its versatility , it will not
present many requirements of the system and can be installed
in practically any type of computer (laptop or PC). Operators