3D digital investigation on diseases of tibet murals

Murals are the important components of culture and arts of Tibet. Unhappily, all of them have been ruined or are being ruined by such diseases as cracks, hollowing, salting, shedding, bleaching, discolouration, erosion and so on. The original data collection and disease inspection of murals is an important and complicated task for mural preservation. We describe a hardware and software system for 3D digital investigation on diseases of Tibet murals under non-laboratory conditions. Our system employs laser triangulation rangefinders, laser time-of-flight rangefinders, digital cameras, and a suite of software for acquiring, computer-Aided modeling, disease marking and disease reporting. We digitized the whole prayer-wheel gallery with about 700m2 of Jokhang Temple including 6 seriously damaged murals. We discussed the challenges we faced in 3D technology applying to investigation on diseases of murals. We focus in particular on processing huge laser scanning data and building a metrological 3D orthophoto model. We proposed a systemtic method of investigation on diseases of murals by integrating of 3D laser scanning and digital photogrammetry based on multiview geometry, not only the geometric and texture information of the murals are completely fused, but also the location, length and area of mural diseases are measured.