Deep Underwater Surveys by Photogrammetry for

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Underwater Archeology and Marine Biology
Sorrento, 16th April 2015
Pierre Drap
CNRS, LSIS laboratory
Marseille, France
Jean-Christophe Sourisseau, Archaeologist, CCJ, Aix en Provence, France
Timmy Gambin, Archaeologist, University of Malta
Luc Long Archaeologist DRASSM, France
Joaquim Garraboum CSIC, Marine Biology, Barcelone, Spain
Bertran Chemisky, COMEX, Marseille, France
o What should be a survey ? Filling the gap between knowledge and
geometry …
o Underwater photogrammetry for archaeology, focusing on
geometry. The beginning, close to Marseille: 1970
o Deep Underwater Survey by photogrammetry: The Geometry
o The photogrammetric tool
o Application to underwater archaeology
o Application to marine biology
o What about knowledge?
o Ontologies for photogrammetry and archaeological artifact
o Using knowledge for 3D reconstruction in naval archaeology
o Merging survey with different resolution
What should be a survey ?
- A survey is an interpretation of the «real world»
- need to be connected with documentation
- need a measuring tool
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Hand made design
Photography
Photogrammetry
Laser scanner
SONAR
…
-…
3D Scan mensi
Andrea Palladio
1970
First underwater photogrammetric survey
for archaeology in Marseille,
Bernard Lioux,
Wreck 3,
Planier, Marseille.
Seven years before, 1963,
Stereo photogrammetry from submarine
Yassi Ada, 1963,
35 meter deph
Submarine Asherah
Georges Bass
La Madrague de Giens,
1972
Giens, France
Antoinette Hesnard
Photogrammetry and
Cartography according
to specific request
Done in 2008
Wreck: Cap Bénat 4, 328 m
1981, Cyana Ifremer
DRASSM
By courtesy Luc Long
Cap Bénat, 328m, 1981
Plage d’Arles 4, 662 m 1993
Plage d’Arles 4, 662 m
1993
Grand Ribaud F (61 m)
DRASSM
2000-2002
COMEX
CNRS
Photo: F. Bassemayousse ©
Deep excavation by blaster
3D Reconstruction
Photograph
Photo: F. Bassemayousse
The rov3D project, COMEX - CNRS/LSIS
Constraints:
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Non intrusive survey, no contact
High accuracy result
Large scale result
Possibly embedded in a small ROV
No sophisticated device, inertial central, High resolution acoustic device, ect…
Real time evaluation in order to be sure all needed data are captured
s
Proposed solution
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Full optical survey, photogrammetry
Three digital camera synchronized
Two low resolution, one high resolution
One computer embedded in the ROV for storage and preliminary process
One computer on board, recieving data from ROV and building
Visual odometry real time with ROV trajectory and sparse cloud of 3D points
Off line, days after, high resolution 3D model reconstruction
Synchro bloc
10Hz, 2Hz
2 Hz
10
Hz
10
Hz
Synchronized LED strobe
Calibrated triplet camera bar
Image
memory
management
10 Hz
Extraction
feature
Points
from 2
stéréopair
at t, t-1
Computer Embedded in ROV
rov cable,
IP com
3D point
computation
at
10 Hz
3D / 2D
Visualization
3D + coulour
Visual odometry
≈ 300 pt
Surface computer used for ROV guidance,
real time ROV location display
rov 3D / real time survey
Devices on ROV
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3 synchronized camera
1 High resolution (6576x4384)
2 Low resolution (1936x1456)
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1 computer embedded in ROV
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Ethernet com
rov 3D: Experimention on Cap Bénat wreck, 328m depth
First original survey, 1981,
now from ROV:
Visual odometry
Real time
Guidance help
Short results
given on board
rov 3D: Experimention on Cap Bénat wreck, 328m depth
3 hours on site, ROV, 2 days process off line.
rov 3D: Experimention on Xlendi wreck, Malta, 100 m depth
From submarine, both visual inspection and survey
3 hours on site, ROV, 2 days process off line.
Knowledge representation: ontologies on photogrammetry and CH connection (alignment) between local CH object and CIDOC‐CRM
OWL / JAVA
Procedural attachment
CIDOC CRM
Founding known object in 3D cloud of points
Using 3D Descriptor extraction for interest point
A lot of methods Chua et Jarvis “Point Signatures”
Sun et Abidi 3D “Point Fingerprint”
Johnson “Spin images”
Tombari “SHOT”
We develop another method: 2D slicing or ‘level curve’
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Founding known object in 3D cloud of points
Founding an instance of a theoretical model present
in a measured site … with several problems, resolution accuracy …
Slice method is fine but … need approximate values …
Ships were built by people, and
human error, combined with the
limitations of the building materials,
make the final result different from
the conceived model:
a)
b)
c)
d)
José Luis Casaban
with Filipe CASTRO,
lines are not parallel,
surfaces are not even,
distances are not regular
edges are eroded...
University of TEXAS, TAMU
 Red coral measurment
 Often by diver because Dificult
to reach
 Need to choose the right part
 Difficult to take oly two good images
 Orient 2 to 10
 Use by stereo pair
 Impossible to use correlation
 The tree structure is an obstacle to automation
 Manual shooting
 Manual measurement
Managing data
two kind of data:
‐ Random quadrat
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Fixed transect
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We have more than 10 years
of photogrammetric
campaign
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Difficulties:
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Having a continuity,
In the method,
people, software
Photogrammétrie Genetic study
High definition Cartography
Genetical distance
High definition survey
of coral structure
White coral measured in canyon de Cassidaigne,
close to Marseille, France. 250 m depth.
Challenge: complex terrain, non DEM representation…
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Deep Underwater Surveys by Photogrammetry for

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