Tools for inverse mapping and visualization of multi-spectral image data on 3D scanned representations of drawings

A new prospective for the study, documentation and presentation of Cultural Heritage is opened by the joint usage of the tools for the automatic reconstruction of digital 3D models and the instruments for interactive 3D visualization. New techniques are available to perform high-resolution sampling of both the shape and the multi-band reflection properties of painted surfaces. The digital 3D models produced are extremely accurate and rich of information, as it has been proved in the experiments run on the Leonardo's Madonna of the Yarnwinder. This paper presents an overview of the techniques needed to build high-quality 3D models from the raw data produced by the scanning devices and describes how to process those models to make them usable in interactive applications. A very critical point is how to integrate the reflection properties with 3D shape models; this integration (based on texture mapping) allows us to produce textured 3D models that allow a joint visualization of shape and color attributes. The interactive visualization tools developed by ISTI-CNR are described, presenting both their features and potential for the visual presentation and analysis of works of art. Examples of the results obtained on the Madonna of the Yarnwinder are presented.