The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
Publications Copernicus
Articles | Volume XL-5
06 Jun 2014
 | 06 Jun 2014

Modelling the appearance of heritage metallic surfaces

L. MacDonald, J. Hindmarch, S. Robson, and M. Terras

Keywords: Cultural Heritage, Imaging, 3D model, Photogrammetry, Photometric stereo, Rendering, Specularity

Abstract. 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.