Modelling the appearance of heritage metallic surfaces

• Main Authors: L. MacDonald, J. Hindmarch, S. Robson, M. Terras
• Format: Article
• Language: English
• Published: Copernicus Publications 2014-06-01
• Series: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
• Online Access: https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XL-5/371/2014/isprsarchives-XL-5-371-2014.pdf

Polished metallic surfaces exhibit a high degree of specularity, which makes them difficult to reproduce accurately. We have applied two different techniques for modelling a heritage object known as the Islamic handbag. Photogrammetric multi-view stereo enabled a dense point cloud to be extracted from a set of photographs with calibration targets, and a geometrically accurate 3D model produced. A new method based on photometric stereo from a set of images taken in an illumination dome enabled surface normals to be generated for each face of the object and its appearance to be rendered, to a high degree of visual realism, when illuminated by one or more light sources from any angles. The specularity of the reflection from the metal surface was modelled by a modified Lorentzian function.