Photos: Richard Stroud
Surface Textures of Carved Rocks Revealed
In most cases, the surfaces of the carved stones have been exposed to weathering over thousands of years. This, coupled with other agents of surface degradation, can make the carvings quite faint in places.
During October 2012, the CSI: Rombalds Moor team invited Sarah Duffy (then PhD candidate at York University) to present her research into the uses of Polynomial Texture Mapping (PTM), and to discuss the possibility of carrying out a trial of this technique as part of the project. This technique uses an image-based recording method that captures information about surface reflectance and produces and interactive surface map of the feature. Controlling the light source is key to this technique, and so it is undertaken at dusk.
After the early spring snow had finally melted, Sarah ventured back to Ilkley Moor to carry out some trials of the technique in the field. The team were really interested to see the technique in action and examples of the results can be viewed on YouTube (click the carved stone to see the video).
To find out more, see the video posted on our YouTube channel where Sarah Duffy and Richard Stroud (consultant on the project) talk about this technique.