Polynomial Texture Mapping at Portus
Polynomial Texture Mapping (PTM) has been employed throughout the AHRC Portus Project. It is a technique that enables the production of detailed surface models of particular artefacts from a series of digital photographs (Malzbender et al 2001; Mudge et al 2005). This technique is achieved by taking multiple photographs of an object from a fixed location, with a controlled light source moved between each exposure, or by deriving the light source’s location and orientation from highlights appearing on a reference object. The resulting series of images is used to produce a single PTM file via the HP Labs PTM fitter software. The PTM viewer enables a virtual light source to be moved across the virtual scene. The viewer can also vary lighting intensity, add additional virtual lights, derive surface models and to carry out image processing tasks such as edge detection.
Example techniques of Polynomial Texture Maps produced by the Portus team:
- PTM of marble head excavated at Portus
- Brick stamp from Portus
- Laser scan of brick stamp from Portus
- Head of Amazon statue at Herculaneum
- Laser scan of Amazon