Polynomial texture mapping and related imaging technologies for the recording, analysis and presentation of archaeological materials

Abstract

Polynomial Texture Mapping (PTM; Malzbender et al 2001) uses multiple images to capture the reflectance properties of a given surface. Multiple captures may be combined in order to produce interactive, relit records of the material recorded. In addition recent research enables the capture and rendition of interactive PTMs for detailed examination of surface details. Cultural heritage examples of the technology include work on Cuneiform tablets, numismatic archives and lithic artefacts.This paper will describe the PTM data capture and processing technologies developed by the University of Southampton, with support from Hewlett Packard Labs Palo Alto. It will also identify the perceived archaeological potential of additional recording to supplement the standard PTM datasets, including the recording of the surface BRDF (bi-directional reflectance distribution function) and accurate extraction of surface normals. Such data offer considerable, under-exploited value in production of comparative conservation datasets. They also enable new forms of analysis, and the possibility for a step-change in the visual fidelity of reconstructions of archaeological surfaces.Case studies will include ongoing work on the examination of Roman wall paintings, Roman stylus writing tablets, medieval wood, bronze artefacts from a maritime contexts, Neolithic architectural plaster, excavation contexts, brick stamps and sculpture. Each of these presents particular challenges and opportunities for recording, analysis and presentation.The paper will conclude by identifying the synergies between PTM, related imaging technologies, photogrammetry and non-contact digitisation through recent case studies on African rock art and on excavated material from the Portus Project (www.portusproject.org). It will identify the ongoing challenges and proposed future developments.<br/