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COST-EFFECTIVE ROCK-ART RECORDING IN A PRODUCTION ENVIRONMENT: IS THERE A WIDER MESSAGE?. Jim Chandler, Loughborough University, UK Paul Bryan, English Heritage, UK. CIPA 2005, Torino. Paper: “ RECORDING ABORIGINAL ROCK ART USING CHEAP DIGITAL CAMERAS AND DIGITAL PHOTOGRAMMETRY”
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COST-EFFECTIVE ROCK-ART RECORDING IN A PRODUCTION ENVIRONMENT: IS THERE A WIDER MESSAGE? Jim Chandler, Loughborough University, UK Paul Bryan, English Heritage, UK CIPA Congress, Athens- Low cost photogrammetric systems
CIPA 2005, Torino • Paper: “RECORDING ABORIGINAL ROCK ART USING CHEAP DIGITAL CAMERAS AND DIGITAL PHOTOGRAMMETRY” • Method applied to record 1500 rock art motifs in UK CIPA Congress, Athens- Low cost photogrammetric systems
Presentation structure • Review method- briefly • Application in a production environment, using volunteers! • Lessons learnt • Concluding remarks/message CIPA Congress, Athens- Low cost photogrammetric systems
Method- fieldwork • Cheap digital cameras • Simple image acquisition • Simple control: • Scalebar • Targets CIPA Congress, Athens- Low cost photogrammetric systems
Method- processing • Simple/commercial software • Leica photogrammetry system (LPS) • Cost- $20K (USD) CIPA Congress, Athens- Low cost photogrammetric systems
Method- Outputs • Digital Elevation Models (DEMs) • Accuracies- 2-3mm • Orthophotos Visualisation “fly-thru” CIPA Congress, Athens- Low cost photogrammetric systems
Northumberland and Durham Regional Rock Art project • Pilot project originally launched in 2004 • Partnership between English Heritage and the County Councils for Northumberland and Durham • Loughborough University advising on the photogrammetry CIPA Congress, Athens- Low cost photogrammetric systems
Image courtesy of Tertia Barnett 3D Laser scanning? Superb results! BUT problems with: shading, expertise, expense and portability! CIPA Congress, Athens- Low cost photogrammetric systems
The way forward? • 60 volunteer workers identified • Equip with cheap digital cameras!? • Train for photogrammetric image capture • Measurement? CIPA Congress, Athens- Low cost photogrammetric systems
Camera calibration • Calibrated at 1.5m distance: 2x in July 2005 + July 2006. • Stable over 1 year period Radial distortion differences with respect to a mean curve for all cameras • Also, consistency in manufacture! Wackrow, R., Chandler, JH, Bryan, P. 2007. Geometric consistency and stability of consumer-grade digital cameras for accurate spatial measurement. The Photogrammetric Record 22 (118): 121–134. CIPA Congress, Athens- Low cost photogrammetric systems
Training Workshop, April 2005 • Simple stereo/flexible data acquisition • Basic control • Basic photogrammetry • Further guidance • Telephone/email support • Direct field support CIPA Congress, Athens- Low cost photogrammetric systems
Early experience • Enthusiasm! • Even or raking light? • Topcon PI 3000 software • Just image capture or full data acquisition? CIPA Congress, Athens- Low cost photogrammetric systems
Image acquisition and training of volunteers (courtesy: Tertia Barnett) Further refinement • Larger panels • Routine measurement BY VOLUNTEERS! • DEMs 2mm and 10mm point spacing (DXF) • orthophotographs (JPEG) and virtual modelling (VRML) • 95% of panels measured BY VOLUNTEERS! CIPA Congress, Athens- Low cost photogrammetric systems
Archiving via ADS (Archaeology Data Service) • Archiving strategy includes dissemination of acquired data-sets • Includes raw-stereo-photography and processed data: • VRML + DXF • PI-3000 project files • Original imagery http://ads.ahds.ac.uk/ CIPA Congress, Athens- Low cost photogrammetric systems
Lessons learnt • Technology and the volunteer. video • Don’t underestimate • Added political benefits! • Hi tech or low? CIPA Congress, Athens- Low cost photogrammetric systems
Conclusion • Low cost, consumer-grade digital cameras can play an important role in heritage recording • Low cost/simplified fieldwork- volunteers, many advantages! • More emphasis on low cost/simple solutions? Publications: • Rock Art Research- journal paper, Nov 2005 • CIPA conference papers, Torino/Athens- Sept. 2005, Oct 2007. • Photogrammetric Record- journal paper, March 2007 • “Applications of 3D measurement from Images”, Book- Sept. 2007 j.h.chandler@lboro.ac.ukhttp://www-staff.lboro.ac.uk/~cvjhc CIPA Congress, Athens- Low cost photogrammetric systems