Arts Digital Humanities Summer School location:Leuven date:8-19 September 2014
See the Surface. Imaging and measuring surface characteristics of medieval library materials by photometric stereo (RICH Project)
The RICH project is surveying the possibilities of RTI to detect material characteristics, decorative issues, damages, the effects of old and recent restoration- and conservation treatments on graphic materials: paper, leather, wood, textiles and parchment. The technique is based on polynomial texture mapping, also known as Reflectance Transformation Imaging (RTI), a technique of imaging and interactively displaying objects under varying lighting conditions to reveal surface phenomena. The underlying processing is based on the extraction of surface characteristics using methodologies such as photometric stereo and BRDF analysis (Bidirectional Reflectance Distribution Function). The imaging module is a hemispherical structure dotted on the inside with 260 LED-lamps and a single downward looking video camera (28 million pixels). The RICH mini-dome is specifically adapted to document fragile documentary heritage but can also be used for other materials. After processing the raw data, the software allows the researcher to manipulate the lightning angles interactively to analyze the topography of objects. RTI can create new models of access to study graphic materials and book-archeological features. The presentation will focus on the possibilities of the RICH mini-dome technology for art technical and conservation science applications. The implementation of a scaling and measuring tool in the software enables the researcher to export graphically the dimensions and changes of topographic characteristics. The technology gives precise information during comparison of almost exact copies of artefacts, or comparing alterations before and after interventions or exhibitions. Presented cases will illustrate the imaging of 14th century manuscript illuminations and writing, an early 15th century polychrome leather casket, the KU Leuven University seals and medieval blind tooled book bindings.
Link PPP presenration: https://www.arts.kuleuven.be/digitalhumanities/documenten/rich-dhss20140908.pdf