become "lost" in areas of similar image appearance
such as reasonably extensive areas of uniform grass
coverage. Points in these difficult areas did not
contribute to the model.
The orthophoto was produced. A grid and title block
were added and then the orthophoto was printed out
on an HP Laser Jet printer.
The test orthophoto map is shown below.
DMAP Test Orthophoto
Fig. 1 Test Orthophoto Map
9. PROJECT RESULTS
The results were very pleasing in that we had
produced an orthophoto from video imagery using a
personal computer digital photogrammetric system.
The resolution of the image was a limiting factor. An
estimate of the accuracy achieved was about +1m on
the ground or 4 pixels on the image.
The imagery was effected by troublesome vibration
as well as irregular motion of the flight path. The
vibration most certainly affected the level of accuracy
achieved.
The procedure for producing the orthophoto was
straight forward although the correlation algorithm
was sometimes limiting.
162
10. FUTURE DIRECTIONS
There are three main steps to be taken in order to
improve and refine the technique.
Firstly, geometric restitution can be improved by
applying accepted techniques such as camera
calibration or adopting a procedure which minimises
the need to calibrate.
Secondly, software with a more sophisticated
correlation algorithm needs to be used to improve the
reliability of DEM generation.
Thirdly, and perhaps most importantly, platform
stability and positioning needs to be improved
substantially in order to make the technique more
efficient. This can be achieved by using a purpose
built RPV controlled by commercially available
avionics components previously described.
11. CONCLUSIONS
The project has shown that orthophotos can be
produced from video imagery acquired from a
remotely controlled aeroplane and using personal
computer based software.
It is clear that the future direction is in the adoption
and use of avionics components.
The low cost of the technique and its components
would seem to indicate that possible applications
such as project mapping for subdivision design, map
revision, mapping for urban planning, environmental
monitoring and GIS mapping are limitless.
12. ACKNOWLEDGEMENTS
The authors wish to thank the following people for
their valuable assistance in making this project
possible.
James B Oliver of Protectol Pty Ltd for his
enthusiastic willingness to modify a pristine model
aircraft for our purpose and the RPV pilots, Noel
Wilson and Ray Dixon. Joe Van der Maat, Pam
Kogen and Fiona Bishop from QUT's Audio Visual
Services Division and lan Hutson from QUT's Visual
Arts Unit for the supply of the camera and the
subsequent frame grabbing and video editing.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996
Atkinsol
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Atkinso
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Chapm:
Collecti
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Slama,
Photogt
Photog
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