Reflection Transformation Imaging and Virtual Representations of Coins from the Hospice of the Grand St. Bernard

Abstract

Reflection transformation imaging offers a powerful new method of documenting and communicating numismatic cultural heritage information. The challenges of documenting numismatic material will be examined along with the limitations of traditional documentary techniques. Previous uses of structured light scanning and PTMs in numismatic documentation are reviewed and evaluated. A novel, low cost method for capturing PTMs at remote locations and subsequent data processing operations is described. Reflection transformation imaging is shown to capture more complete documentation than traditional photographic methods and communicate this information with ease through digital media. The advantages of interactive relighting of numismatic PTM images in conjunction with enhancement operations are explored along with the potential of informed choice of the most information rich illumination directions. Advantages of joint capture of structured light and PTMs are examined including the inherent registration of range and normal data, using range and normal information together to improve 3D position accuracy, and the enhanced evidentiary reliability that results.