Polynomial texture mapping
Polynomial texture mapping (PTM), also known as Reflectance Transformation Imaging (RTI), is a technique of imaging and interactively displaying objects under varying lighting conditions to reveal surface phenomena. The data acquisition method is Single Camera Multi Light (SCML).[1]
Origins
The method was originally developed by Tom Malzbender of HP Labs in order to generate enhanced 3D computer graphics and it has since been adopted for cultural heritage applications.[2]
Methodology
A series of images is captured in a darkened environment with the camera in a fixed position and the object lit from different angles (Single Camera Multi Light). Interactive software processes and combines the set of images to enable the user inspecting the object to control a virtual light source.[2] The virtual light source may be manipulated to simulate light from different angles and of different intensity or wavelengths to illuminate the surface of artefacts and reveal details.[2][3] Open-source tools for processing the captured images and publishing the resulting relightable images on the web are freely available.[4]
Applications
Polynomial texture mapping may be used for detailed recording and documentation, 3D modeling, edge detection, and to aid the study of inscriptions, rock art[5] and other artefacts.[3][6] It has been applied to hundreds of the Vindolanda tablets by the Centre for the Study of Ancient Documents at the University of Oxford in conjunction with the British Museum.[7] It has also been deployed, by Ben Altshuler of the Institute for Digital Archaeology, to scan the Philae obelisk at Kingston Lacy and the Parian Chronicle at the Ashmolean Museum; in both cases scans revealed significant, previously illegible text.[8][9][10] Method was also used for identifying microscopic worked antler from Star Carr and recording ancient rock art in Armenia.[11]
A 'dome' supporting twenty-four lights has been used to image paintings in the
The technique is now also finding uses in the field of forensic science, for example in imaging footprints, tyre marks, and indented writing.
See also
- Multispectral image
References
- S2CID 216318287.
- ^ a b c "Archaeology and polynomial texture mapping". The Economist. 25 March 2010. Retrieved 8 March 2011.
- ^ a b "Polynomial texture mapping". University of Southampton. Retrieved 8 March 2011.
- ISTI - CNR.
- ^ Mourey, Jules Masson (January 2019). "First application of Reflectance Transformation Imaging (RTI) on Prehistoric Rock Engravings of the Monte Bego Region (Tende, Alpes-Maritimes, France)". International Newsletter on Rock Art (84): 24–30.
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: CS1 maint: date and year (link) - ^ "Polynomial texture mapping". University of Southampton. Retrieved 8 March 2011.
- . Retrieved 8 March 2011.
- ^ "The Parian Marble at The Ashmolean Museum". Institute for Digital Archaeology. Retrieved 24 September 2015.
- S2CID 171785310.
- ^ "The Digital Marmor Parium Project at the University of Leipzig".
- ^ Kennedy, Hannah. "Visual interpretation, survey and graphics: adding value to archaeology" (PDF). 2020: Yearbook and Directory: 17 – via Chartered Institute for Archaeologists.
- ISBN 978-0-7506-6183-6.
- .
- ISBN 9781906124885
- ISBN 9783905673760
- ^ "Custom Imaging".
External links
- Polynomial texture mapping (Hewlett Packard)
- Project applying polynomial texture mapping to an ancient sculpture (University of Southampton - Archaeological Computing Research Group)
- Reflectance Transformation Imaging (RTI) (RTI overview on the Cultural Heritage Imaging website)
- Sixteen interactive renderings of Polynomial Texture Mapping (or RTI) of 8th-century illuminated manuscript, revealing difficult to see dry-point writing (University of Oklahoma)
- Heritage Visualisation website with Pixel+ viewer and an integration solution for Single Camera Multi Light datasets