Technology

Topics:

• Surveying
• Remote Sensing
• Panoramic Photography
• Laser Scanning
• Kite Photography
• HDR Photography
• HDD Survey
• GPS Surveying
• Digital Video

Laser Scanning

High definition 3D scanning can, in general terms, be defined as any instrument that collects 3D data of a given surface or object in a systematic, automated manner, at a relatively high rate and in near real time (Boehler and Moebs 2001). This excludes many traditional survey instruments that do not meet these three requirements. Traditional methods such as tapes, theodolites and more modern technology such as total stations and GPS provide accurate but relatively slow and cumbersome methods for gathering spatial data (Addison 2001). High definition survey can thus be distinguished from traditional survey by the rate at which the physical world is sampled. High definition survey devices such as laser scanners are able to sample at rates that were previously impractical, resulting in high definition data and, correspondingly, very large datasets.

Three dimensional scanning technologies are generally based on one of three methods:

• Time of Flight: A technique by which a laser pulse is emitted from the instrument and the time of flight is measured, from which the distance to the object can be determined.


• Phase Comparison: The instruments emits a stream of light with a known frequency and phase and by comparing the emitted phases to the returned phases the distance to the object can also be determined.


• Triangulation: This system utilizes two sensors which simultaneously record the reflected laser pulse and determines the dim.

Three-dimensional scanning can be broken down into two classes of instrument based on the optimal distance of the sensor. Long Range LIDAR technology was initially developed as a tool for the creation of as-built drawings in complicated retrofit and construction projects such as oil refineries (where the intricate infrastructure would render traditional surveying techniques inadequate). Typical distances of long range systems range from a minimum of one to two meters to a maximum distance in the hundreds of meters. The table below gives the specifications for the Cyrax 2500 system, which is a typical long-range scanning system that is widely used today. This range and resolution makes long range scanning systems perfect for the recording of architectural scale features and objects. The use of 3D scanning in cultural heritage is relatively new, but is equally applicable to the technique.

For more information on the use of this technology in heritage documentation and Digital Preservation, please see the following articles in our Knowledgebase:

Investigating the Accuracy of a Mensi GS100
CIPA: Heritage Documentaion
3D Laser Scanning for Heritage
Collection and Archiving of Point Cloud Data for English Heritage
Caltrans Standards and Specifications
Investigating Laser Scanner Accuracy
Accuracy Comparisons of Terrestrial Laser Scanning Systems
Leica Scanstation 2 Brochure
Leica Scanstation 2 Data Sheet
Leica Scanstation Data Sheet
Leica HDS6000 Data Sheet
Leica HDS6100 Brocure
Leica HDS6100 Data Sheet
'Big Data'
3D Laser Scanning Forum
FARO Laser Scanner Systems Product Catalog
FARO Photon 80/20
Optech ILRIS-3D Brochure
How to Cut Sections in the CyArk Point Cloud Viewer
Crafting Quality Laser Scan Animations Using Cyclone
Heritage 3D Case Studies

References

• Sternberg, H., T. Kersten, I. Jahn, and R. Kinzel. "Terrestrial 3D Laser Scanning - Data Acquisition and Object Modelling for Industrial As-Built Documentation and Architectural Applications." The International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol XXXV, Commission VII, Part B2. 2004. 942-947.
• Salemi, G., V. Achilli, D. Bragognolo, A. Menin, and F. Ru. "Data Fusion for Cultural Heritage Documentation: From the Panoramic Imaging to 3D Laser Scanning." CIPU 2005 XX International Symposium (26 September - 01 October 2005).
• Levoy, M., K. Pulli, B. Curless, S. Rusinkiewicz, D. Koller, L. Pereira, M. Ginzton, S. Anderson, J. Davis, J. Ginsberg, J. Shade, D. Fulk. "The Digital Michelangelo Project: 3D Scanning of Large Statues." In SIGGRAPH 00 (2000).
• Finat, J., J.J. Fernandez-Martin, L. Fuentes, M. Gonzalo, J. Martinez-Rubio, and J.I. SanJose. "Ordering Criteria and Information Fusion in 3D Laser Surveying of Small Urban Spaces." ISPRS (2005).
• Beraldin, J.A., M. Picard, S. El-Hakim, G. Godin, V. Valzano, and A. Bandiera. "Combining 3D Technologies for Cultural Heritage Interpretation and Entertainment." Berladin, J.A., S. El-Hakim, A. Gruen, and J. Walton (eds). Videometrics VIII, SPIE Vol. 5665: 108-118.
• Barber, D., J. Mills and P. Bryan. "Laser Scanning and Photogrammetry: 21st Century Metrology." Proceedings of the Surveying and Documentation of Historic Buildings - Monuments - Sites Traditional and Modern Methods, CIPA 2001 International Symposium, Potsdam (2001).
• Santana-Quintero, M. The Use of Three-Dimensional Techniques of Documentation and Dissemination in Studying Built-Heritage. Department of Architecture. Leuven, University of Leuven, 2003: 379.
• Boehler, W. and G. Heinz. "Documentation, Surveying, Photogrammetry." XVII CIPA International Symposium. Recife, Brazil, Proceedings (1999).
• Boehler, W., G. Heinz and A. Marbs. "The Potential of Non-contact Close Range Laser Scanners for Cultural Heritage Recording." XVIII CIPA International Symposium, Potsdam, Germany, Proceedings (2001). 8.