Archaeology and art history is currently going through a period of striking technical transformation. New apparatus, such as the 3D laser scanner, and sophisticated software applications are revolutionising the scanning, cataloguing and conservation of all kinds of cultural assets. At the same time, this opens up new ways for museums to communicate historical knowledge. Just how fascinating and diverse the current possibilities are was demonstrated last week during an international workshop entitled "Recording, Modeling and Visualization of Cultural Heritage", which was carried out by two ETH professors, Armin Grün from the Institute for Photogrammetry and Remote Sensing (1) and Luc van Gool from the Communication Technology Laboratory at Centro Stefano Franscini in Ascona (cf. box).

Optional profiles of excavations

The first changes happened in the realm of archaeological excavations. New equipment makes it possible today to document individual, excavated layers, constantly and digitally in three dimensional resolution. Among other things this means that, at a later date, any vertical profile across the excavated area can be visualised. Something like this would have been unthinkable just a few years ago, said Michael Doneus from the University of Vienna. In addition, geographical information systems also allow all kinds of information from excavations to be combined–for instance the exact position of a find or area-wide geophysical data–and illustrated with three-dimensional models of the terrain. For the ensuing capturing and cataloguing of the finds, valuable objects are no longer merely drawn and photographed but, increasingly, subjected to 3D-scans. On the monitor the scanned objects can then be studied from all sides. If necessary, missing parts can be "virtually" added.

Although technical progress is considerable, the experts who gathered for the workshop were not entirely satisfied. Indeed, a number of problems remain to be solved in many fields, because with complex objects–which is often the case when it comes to valuable artefacts–3D-scanners quickly reach the end of their capacities. Users have to tread a fine line. On the one hand, there is the desire to obtain images that are as detailed as possible so that fine structures are made visible, which is particularly interesting from an art historical point of view. But on the other hand, one has to be careful that the high resolution does not create artefacts that have no basis in reality. A few suggestions were exchanged at the workshop on how to improve the 3D laser scans. The sometimes lively discussions illustrated that it was not just a question of technical hair-splitting.

Hollywood shapes views of history

One positive aspect was underlined during the workshop, namely the new teaching perspectives opened up by the new visualization techniques. A virtual tour of Castle Neuschwanstein in Bavaria, for example, or the reconstruction of an antique city where its buildings appeared in all their glory, met with a lot of interest from the non-experts present. The goal should be to teach history in a way that showed cultural assets and objects in their historical context, postulated Pierre Boulanger from the University of Alberta. Epic films à la Hollywood had informed the view of the majority of people to a far stronger degree than dry, scientifically accurate exhibitions in museums.

That the public at large is fascinated by the possibilities of reconstructing destroyed cultural heritage is fully borne out, for instance, by the interest shown in efforts directed at the reconstruction of the Buddha statues in Bamiyan, Afghanistan. Within the framework of a project (2) Armin Grün and his team at the Institute of Geodesy and Photogrammetry at ETH Zurich have reconstructed the monumental statues in the rock-face. "When we started the project, one scientific question stood in the foreground. We wanted to investigate how we could make a digital reconstruction of an object of which only individual pictures existed. When the Bamiyan statues were destroyed by the Taliban in 2001 our project became topical in a way we couldn't have foreseen."

For their work the team of researchers at ETH collated pictures from many–very different–sources, ranging from satellite images all the way to old photographs taken by tourists. Whether the virtually reconstructed statues will ever be reconstructed in reality is still unclear. "We should know more after an up-coming conference on the subject that will take place in Afghanistan," said Armin Grün. "In the end, Afghanis themselves must decide whether they really want to reconstruct the statues, whether they will be brought back to life virtually with laser projections or whether the recesses in the rock-face will remain empty."