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International Archives of the Photogrammetry, Remote Sensin
g and Spatial Information Sciences, Volume XXXIX-B4, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
They can also be used jointly with remaining cameras to
colorize the cloud of points. In order to verify travel trajectory
and to release cameras, an odometer is fixed to one wheel of the
axle set. The whole equipment set is mounted on a Structural
section fixed to the flat car deck. The diagram of arrangement of
particular system elements in different variants of installation of
high-resolution digital cameras is shown in Fig. 9. The module
of 3 scanners is marked in red, 4 photogrammetric cameras are
marked in grey and yellow (2 black and white cameras and 2
colour cameras, respectively), and 2 colour video cameras are
marked in yellow with additional "v" letters on them. Red
rectangle on the wheel shows the position of odometer.
5. SUMMARY AND CONCLUSIONS
The goal of the paper was to show results of research works
completed by a research and development team from the AGH
University of Science and Technology in Cracow, Poland,
under the project of constructing a prototype of flatcar to
measure railway clearances.
In the first part of the project a review of existing systems was
made (Section 1.2). Based on preliminary literature survey, two
different measurement systems were selected to test flaws and
advantages of particular methods. Next test measurements,
described in Section 3, were performed on a selected railway
route sector.
The final stage of research was proposing a model of a ground-
based scanner railway lorry with a gco-referential module and a
photogrammetric module, which was described in Section 4.
It was assumed that using presently available scanners and upon
the application of perpendicular scanning together with
diagonal one, it would be possible to guarantee detection of all
obstacles in the track-side area, with one of their dimensions
higher than 5 cm. It is, however, impossible to fully identify
what a reflecting surface is. Therefore, upon detection of so
small, "single-point details" it is necessary to use cameras and
to look over images showing the place under discussion.
Experience. demonstrates that looking over images was the
Weakest side of the photogrammetric technology due to the
labour intensity and possibility of omitting objects that enter the
clearance area. Also measurement performed on a 3D stereo-
model is manual, with a low rate of automation. This results
from the specificity of the railway zone space, in which objects
subjected to measurement are relatively small, often lofty, with
à relatively distant background recorded between them, which
radically changes the stereoscopic model depth. Hence
photogrammetric support in the form it is used now should be
reduced to an absolute minimum — to clarify doubts that appear
during measurements in the cloud of points (that is,
incidentally).
One of conclusions originating from the completed research
Works is a statement that the cloud of points should develop
from profiling in different directions: perpendicularly and
diagonally to the track axis. Measurement performed on a cloud
of points obtained from perpendicular profiling gives better
accuracy rates but it not always is capable of detecting the
eXistence of objects, especially those small ones, along the
railway track and extending crosswise. Scanning performed in
different directions increases the density of the cloud of points,
Which density is of critical importance for the identification of
details, Average distance between profiles in tested clouds of
Points varied from 0.05 to 0.20 m, with the smaller interval
reached only at low travelling speed. Systems used during tests
Were not able to provide a sufficient data density for a travel
With the Speed of 80 km/h. A specific sufficient density equals
the possibility of detecting details of several centimetres in size.
Therefore, the target system, which has to operate at the speed
of 100 km/h, must utilize both different directions of profiling,
and scanners of higher performance rates.
REFERENCES
BBRT 2011, Balfour Beatty Rail Technologies materials for the
AGH University of Science and Technology. "Limited Gauging
Capability Overview and Consideration of Areas of Support in
PKP PLK's Gauging Research Project".
Schewe H., Hol J, Gründig L. 1999. LIMEZ -
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Obstacles. Third Turkish-German Joint Geodetic Days,
Istanbul/Turkey. Towards a Digital Age, Volume II, page 721-
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Meier J., 2009, a presentation titled LIMEZ III — Der neue
Lichtraummesszug der Deutschen Bahn "Railborn High-Speed
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ACKNOWLEDGEMENTS
This work was funded by AGH University of Science and
Technology, project No: 11.11.150.949 and 5.72. 130.151.
