Surveying, modeling and communication techniques for the documentation of medieval wooden painted ceilings in the Mediterranean area

Wooden painted ceilings of the Mediterranean area in the middle age have their origin in the islamic culture and were then spread in the countries under the dominion of the Arabs; some of the surviving ceilings are now located in Sicily and Spain. In the historic centre of Palermo two well preserved medieval ceilings are still surviving; the first, built in the XII century, is located in the Palatine chapel; the second one, built in the XIV century covers the “Sala Magna” in the Steri of Palermo. The research, focused on the ceiling in the Steri, deals with the definition of a process for the integration of surveying techniques (photogrammetry, laser scanning), modelling processes and communication technologies for the documentation of such artefacts. The documentation of painted ceilings requires the strict integration of photographic and 3D metric data; the existing documentation is usually made of documents (drawings, photographs) that keep geometric and metric data separated from the photographic documentation of the paintings. The first stage in this work is therefore addressed to produce a digital document that combines metric and photographic data in a 3D textured model; in the second stage a vocal guide interacting with the 3D model has been developed; such guide, thought as a support to people visiting the Steri, uses a database with historic contents and symbolic interpretation of the painted scenes to answer specific questions and “take” the visitor close to the related paintings.