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Antique Monument meets Modern Technology:
The 3D Digitisation of the Hadrian's Temple

The so-called Hadrian’s Temple is one of the most famous monuments in the ancient city of Ephesus (Turkey). It occupies a prominent location in the Western section of the Curetes Street, one of the major thoroughfares in the area.

 

Until now, only a plan and a restored elevation have been established and the building therefore has been a subject of controversy for over half a century.
 

A new project initiated by the Austrian Archaeological Institute (ÖAI) and funded by the Austrian Science Fund has set out to address these problems.

 

Project Definition and Objectives

Before any kind of interpretation can be addressed, it is of major importance to clarify the architectural and historical aspects of the structure. The first step towards this goal is to generate a high-definition 3D surface scan of the entire temple in order to produce an up-to date archaeological profile of the building including a detailed stone-by-stone documentation with all its cuttings, tool marks and ornamentation. 

 

A major objective in this context is the creation of orthogonal projections during the data post processing. In addition, these ortho-projections will be used for mapping cracks and fissures by a professional conservator to examine the original building parts of the temple in comparison to its modern additions.

 

Advantages of the Digital Capturing

  • significantly time saving compared to hand drawings
  • no disturbances by scaffolding constructions for an extended period of time
  • only minor disturbances for visitors of the historical site
  • merely objective documentation, elimination of subjective factors

 

Challenges

  • due to the modern reconstruction work, the building and its architectural components
    form a solid structure which cannot be transferred or disassembled
  • size of the building: approx. 10 x 10 m in plan, overall height about 8 m
  • scaffolding to achieve the required working distance
  • digitisation without protective tent: measurments only by night
 

Results and Data Post-Processing

In the course of the scanning project, firstly all scans were aligned and registered in the same coordinate system with reference to the photogrammetric data of the index marks. The overall accuracy of this “constrained alignment” process for the 3D structure of the entire temple is in the range of 1-2 mm, the local accuracy is typically better than 500 μm. In the second phase, all data were merged into combined polygon meshes. Where necessary, small holes could be filled automatically.

 

Another important use of the 3D data is the reconstruction of the complex roof structure over the Hadrian’s Temple. During the course of this project, every individual architectural component of the building complex has been scanned. Together with the 3D picture of the temple itself, it is now possible to verify whether the reconstructed parts do accurately correspond with their architectural remains, especially with regard to their joining and tool marks.

 

The 3D data therefore does not only represent a tool for the documentation of the Hadrian’s Temple, it also provides substantial information to address complex architectural questions about this structure which otherwise could not have been tackled.

 

A final aspect of the data post-processing is the production of 2D orthographic images for publication and cartography purposes.

 

The research was funded by the Austrian Science Fund (FWF): P12345-B51.

 

Detailed information about this project are available in an online article of the Forum Archaeologiae (only available in German).

 

 

 

 

Pictures

Scanning process from different positions
Preparing the 3D digitisation
Scanning by night
Hadrian's Temple
Detail of the Hadrian's Temple