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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part BS. Istanbul 2004
Figure 8: Intelligent control through external images
Dynamic measurement protocol
A continuously growing graphical measurement protocol is
generated through the parametric link between the coordinate
system and the image. In an oriented image, single points and
connecting lines are faded in automatically (figure 9).
Figure 9: Dynamic measurement protocol
Point numbers can be registered for future applications, e.g. for
monitoring or densification of the network or referencing for
photogrammetric purposes. The link between the images and
the coordinates is permanent. Therefore the totalstation can be
adjusted at any time by clicking on the points in the image.
4. FUTURAL DEVELOPMENTS?
In 1994 the first tacheometer with servomotor measuring
reflectorless and directed by computer was developed at
Bochum. This type of instrument is now working worldwide in
various models and applications: in recording, control in
engineering surveying and for setting out. Meanwhile this type
of instrument was modified. To make it more flexible cameras
were integrated into the tube of the telescope (see figure 10).
Two wide-angled cameras with different focal lengths are in the
casing; a third camera is located in the plane of reticule. This so
called ocular camera is automatically focused by a gearing in
the tube of the telescope. The appliance can be remote
controlled through the images and measurements directed
towards the zenith can be done without any problems. For
subsequent identification, the measured points can be
documented at the time of the recording for various purposes.
This is particularly important for work with “natural points”
ocular camera,
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angled
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Figure 10: Integrated cameras and a set of photos of a natural
point
With the aid of the cameras documentation of object points and
directing the instrument via notebook are simpler than using the
photos of the external digital camera described in chapter 3,
because now the parametric orientation is not necessary.
This new type of instrument - robot-tacheometer with integrated
cameras - may be called a *video tachymeter". Maybe in some
years it will be a custom instrument, like the servo-driven
reflectorless measuring tacheometer, which was developed at
university of Bochum ten years ago.
In chapter two and three the broad application spectrum of the
reflectorless measuring servo-driven tacheometer, especially
when using a digital camera was shown. “Low-cost scanning
methods” are possible with this equipment. However it should
not be understood as a competition to Laserscanners but as a
powerful enhancement and sometimes as an alternative.
Everybody has to decide on his own which method should be
chosen, depending on the characteristics of the object, costs and
on the result which is asked.
5. REFERENCES
Juretzko, M. 2003. TOTAL — Tachymetrische Objektorien-
tierte Teil-Automatische Laservermessung. Operation Manual
Scherer, M. , 1995. Ein Expertensystem zur Architektur-
aufnahme — Bausteine auf dem Weg dorthin. Zeitschrift für
Vermessungswesen, 1995, pp. 134-142
Scherer, M., 2002. Advantages of the Integration of Image
Processing and Direct Coordinate Measurement for
Architectural Surveying - Development of the System TOTAL-.
XXIL FIG International Congress, ACSM/ASPRS Annual
Conference, Washington DC 2002 (CD-ROM)
