Virtual Visit
Several techniques have been used to visualize Sagalassos and to recreate it in all its glory.
The video below gives a short overview of the 3d acquisition and rendering of artefacts
in Sagalassos by the PSI-VISICS team of K.U.Leuven.
In this section of the website, we would like to show preliminary results of a number of techniques, which will bring Sagalassos back to a new virtual life.
Shape-from-Video
The Shape-from-Video tool makes it possible to derive a three dimensional
representation of an environment from multiple photographs or video content.
Both a dense (high spatial resolution), textured, geometrical reconstruction
of the environment and the camera trajectory are extracted from these visual
inputs.
Other 3D reconstruction tools exist but use methodologies different
from the Shape-from-Video tool, e.g. laser scanners and grid projectors.
Each methodology has its strengths and weaknesses. The Shape-from-Video
tool is especially designed to supply a good compromise in trading
3-dimensional accuracy for user-friendliness.
The 3D reconstructions obtained by the Shape-from-Video tool demonstrate sufficient
spatial accuracy for most commercial applications while allowing the use of a simple
off-the-shelf camera, a rich freedom of camera motion and a large variety in
environment scale. The Shape-from-Video tool has been developed to operate in
environments with a rich diffuse texture, sufficient 3D content, and mostly static objects.
The following video shows the video material and the resulting 3D model of a Medusa head found at Sagalassos.
3D stratigraphy
As many of the bigger archaeological objects and scenes do not lend themselves to be captured in one continuous image sequence, a new tool ('the Layer Matcher') has been developed that allows for the merger of different 3D reconstructed parts of the same scene in one single framework. This is accomplished by querying the user for some corresponding points between the different reconstructions. This tool demonstrated to be especially useful for the generation of 3D data for stratigraphical layers. It seems to be difficult to capture an entire layer with a single image sequence. The next figure shows how two 3D reconstructions, originating from separate image sequences, are merged together into a single framework by indicating some corresponding points between both reconstructions.
 |
 |
 |
|
Another feature of the 'Layer Matcher' is the ability to merge 3D reconstructions of consecutive stratigrahical layers as the archaeologists progress and uncover new stratigraphical layers, thereby destroying the old layers. The tool makes it possible to keep a 3D record of all layers in time, a valuable advantage due to the destructive nature of the excavation of stratigrahical layers. The next figure demonstrates how two consecutive layers (in time) can be merged together to give an idea of the excavation progress.
 |
 |
 |
|
Reconstruction of Landscapes and Texture
The state-of-the-art in archaeological VR is the repetitive mapping of simple textures, possibly patterns copied from photographs. The proposed techniques make it possible to generate arbitrary amounts of textures, without any verbatim copying or periodicity, but with convincing detail and complexity.
 |
 |
| left image: mountain slope behind Sagalassos in its current state,
right image: virtual reforestation and irrelevant object removal |
|
 |
 |
| Covering of the virtual pillars of the Nymphaeum with synthetic limestone textures. | |