View
1
Download
0
Category
Preview:
Citation preview
Heinz Rüther - UCT
State-of-the-art-technologiesin
Heritage Documentation
The Giraffe Engravingsof Oued Djerat
a TARA project
Heinz RütherUniversity of Cape Town
Geomatics Division
Heinz Rüther - UCT
The field team:
David CoulsonAlec CampbellVictoria WaldockHeinz Rüther
Tuareg GuidesGiraffes
Tasili N’A
jjer
Heinz Rüther - UCT
Technologies employed
1. Aerial & close range digital photogrammetry
2. Satellite imagery, remote sensing and imageprocessing
3. (Laser scanning)
4. Airborne and close range SAR
5. Geographic Information Systems (GIS) and CAD
6. Computer visualisation
7. Data bases
8. Conventional surveying methods
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Photogrammetry
DistortedOriginalImages
Camerastations
Scale discrepancies due to elevation differences
h2
h1
h1 h2
Scale 1 Scale 2
y z
x
Ortho Image Generation
Ortho-rectifiedImages
Camera position and orientation(x, y, z, )
Digital Terrain Model
Heinz Rüther - UCTladder = photo centreunused photo area
Four photos at each setup
• one vertical for final composite
• three oblique to tie images together
Heinz Rüther - UCT
7 * 7 = 49 camera setups with 60% overlap of the verticalimages
Total of about 200 images
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
5000 by 5000 pixels 1 pixel 3 mm
Heinz Rüther - UCT
Linedrawings
in
GIS
format
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Characteristics of terrestrial scanners
Range: 3 - 50 to 800 m
Accuracy: 5-10 mm depending on distance
Minimum point interval : 1 mm
Recent additions to scanners:
Camera with RGB capability
GPS
Heinz Rüther - UCT
15 m
15
m
Laser scan - Low resolution
at 1 mm point spacing
15 000 * 15 000
= 125 000 000 points
X Y Z intensity
= 500 000 000 stored values
or = 875 000 000 with RGB
??? DISPLAY ???
Laser Scan for the Giraffe site
High resolutionclose range
laser
0.4 by 0.4 mcover per
scan > 1000
Set ups
Laser scanning not suitable for giraffe site
Laser scanning not suitable for giraffe site
Heinz Rüther - UCT
Surface representation in laser scan software
Zoomed
out:
Gaps
Best fit Zoomed
in
Smeared
TIN
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Heinz Rüther - UCT
Recommended