Deep Underwater Surveys by Photogrammetry for Underwater Archeology and Marine Biology

Transcription

1 Deep Underwater Surveys by Photogrammetry for Sorrento, 16th April 2015 Deep Underwater Surveys by Photogrammetry for 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

2 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

3 What should be a survey? Deep Underwater Surveys by Photogrammetry for - A survey is an interpretation of the «real world» - - need to be connected with documentation - need a measuring tool Hand made design Photography Photogrammetry Laser scanner SONAR - 3D Scan mensi Andrea Palladio

4 1970 First underwater photogrammetric survey for archaeology in Marseille, Bernard Lioux, Wreck 3, Planier, Marseille.

5 Seven years before, 1963, Stereo photogrammetry from submarine Yassi Ada, 1963, 35 meter deph Submarine Asherah Georges Bass

6 Deep Underwater Surveys by Photogrammetry for La Madrague de Giens, 1972 Giens, France Antoinette Hesnard Photogrammetry and Cartography according to specific request Done in 2008 Sorrento, 16th April 2015

7 Wreck: Cap Bénat 4, 328 m 1981, Cyana Ifremer DRASSM By courtesy Luc Long

8 Cap Bénat, 328m, 1981

9 Plage d Arles 4, 662 m 1993

10 Plage d Arles 4, 662 m

11 Plage d Arles 4, 662 m

12 Plage d Arles 4, 662 m 1993

13 Grand Ribaud F (61 m) DRASSM COMEX CNRS Photo: F. Bassemayousse

14 Grand Ribaud F (61 m)

15 Grand Ribaud F (61 m) Deep excavation by blaster

16 3D Reconstruction Photo: F. Bassemayousse Photograph Grand Ribaud F (61 m)

17 Grand Ribaud F (61 m)

18 The rov3d project, COMEX - CNRS/LSIS Constraints: 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 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

19 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 rov cable, IP com 3D point computation at 10 Hz 3D + coulour 300 pt 3D / 2D Visualization Visual odometry Computer Embedded in ROV Surface computer used for ROV guidance, real time ROV location display

20 rov 3D / real time survey Devices on ROV - 3 synchronized camera - 1 High resolution (6576x4384) - 2 Low resolution (1936x1456) - 1 computer embedded in ROV - Ethernet com

21 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

22 rov 3D: Experimention on Cap Bénat wreck, 328m depth 3 hours on site, ROV, 2 days process off line.

23 rov 3D: Experimention on Xlendi wreck, Malta, 100 m depth From submarine, both visual inspection and survey

24 rov 3D: Experimention on Xlendi wreck, Malta, 100 m depth 3 hours on site, ROV, 2 days process off line.

25 rov 3D: Experimention on Xlendi wreck, Malta, 100 m depth Knowledge representation: ontologies on photogrammetry and CH connection (alignment) between local CH object and CIDOC CRM OWL / JAVA Procedural attachment CIDOC CRM

26 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 -

27 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

28 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) lines are not parallel, b) surfaces are not even, c) distances are not regular d) edges are eroded... José Luis Casaban with Filipe CASTRO, University of TEXAS, TAMU

29 Deep Underwater Surveys by Photogrammetry for Sorrento, 16th April 2015

30 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

31 Managing data two kind of data: Random quadrat Fixed transect We have more than 10 years of photogrammetric campaign Difficulties: Having a continuity, In the method, people, software

32 Photogrammétrie Genetic study High definition Cartography Genetical distance High definition survey of coral structure

33 Deep Underwater Surveys by Photogrammetry for Sorrento, 16th April 2015 White coral measured in canyon de Cassidaigne, close to Marseille, France. 250 m depth. Challenge: complex terrain, non DEM representation 33

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