Virtual reality is a technology that offers promising perspectives for archaeologists. It can help in many ways. New insights can be gained by immersion in ancient worlds, unaccessible sites can be made available to a global public, courses can be given ``on-site'' and different periods or building phases can coexist.
One of the main problems however is the generation of these virtual worlds. They require a huge amount of on-site measurements. In addition the whole site has to be reproduced manually with a CAD- or 3D modeling system. This requires a lot of time. Moreover it is difficult to model complex shapes and to take all the details into account. Obtaining realistic surface texture is also a critical issue. As a result walls are often approximated by planar surfaces, stones often all get the same texture, statues are only crudely modeled, small details are left out, etc.
An alternative approach consists of using images of the site. Some software tools exist, but require a lot of human interaction  or preliminary models . Our system offers unique features in this context. The flexibility of acquisition can be very important for field measurements which are often required on archaeological sites. The fact that a simple photo camera can be sufficient for acquisition is an important advantage compared to methods based on theodolites or other expensive hardware. Especially in demanding weather conditions (e.g. dust, wind, heat, humidity).
The ancient site of Sagalassos (south-west Turkey) was used as a test case to illustrate the potential of the approach developed in this work. The images were obtained with a consumer photo camera (digitized on photoCD) and with a consumer digital video camera.