The Kioutouklou Baba Bekctashic Tekke

Kioutouklou Baba Bekctashic Tekke monument

CETI has prepared a case study of the 3D digitisation of the Kioutouklou Baba Bekctashic Tekke monument, which describes the fieldwork including terrestrial and aerial photography of the monument, terrestrial 3D laser scanning, a total station survey and preparation of a 3D digital replica of the monument's exterior.

The Kioutouklou Baba Bekctashic Tekke monument is located in the middle of a cultivated area on the west coast of the Vistonida lake in Xanthi, Greece. It is considered to be one of the most important Ottoman monuments in the area and may have been built in the late 15th century. The monument was possibly built on the ruins of an Orthodox Christian temple dedicated to Saint George Kalamitziotis.  It is considered to be the grave of a Whirling Dervishe, named Kioutouklou Baba. According to Lowry the term tekke (gathering place for Dervishes) is erroneous as the monument is a tomb (türbe).

Aerial survey of the Kioutouklou Baba Bekctashic Tekke monument

Aerial survey of the Kioutouklou Baba Bekctashic Tekke monument

Fieldwork

The fieldwork was separated into five sessions. The first two involved the terrestrial and aerial photo shooting of the monument. For the terrestrial photo shooting session a DSLR Nikon D40 at 6.1 MP with an 18–55 mm lens along with a tripod have been used. On the other hand, for the aerial photo shooting session, a remote controlled helicopter has been used. The UAV was equipped with a three axis pan-tilt-roll remote controlled camera head (360◦ on the horizontal axis, 220◦ on the vertical axis and a rolling ability of 60◦). A DSLR Canon EOS350d at 8.1MP with an 18–55 mm lens has been used for the aerial photo shooting session. The total number of photographs that has been used for the generation of the 3D model of the monument was 652 (469 terrestrial photos and 183 aerial photos). The average distance of the camera from the monument’s surface was estimated at 4m.

Aerial view of the Kioutouklou Baba Bekctashic Tekke monument

Aerial view of the Kioutouklou Baba Bekctashic Tekke monument

Then, the terrestrial 3D laser scanning session took place. An Optec Ilris-36D time-of-flight range scanner has been used. The system’s specifications indicate a minimum distance of 3m  between the scanner and the surface to be scanned. The system offers 7 mm  standard deviation error for measurements implemented at a hundred meters distance and a 2cm  maximum distance between two sequential points at a thousand meters distance. The integrated digital camera of the scanner has a 3.1 MP CCD sensor but the colour quality is considered to be poor when compared with similar systems. A total of 24 partial scans were captured. The average distance from the monument was 16.55m  while the average distance between two consecutive points was 1.37cm . A complete digitisation of the monument using the range scanner was not achieved. Scaffolding constructions was necessary in order to capture the top of the monument.

Topcon survey of the Kioutouklou Baba Bekctashic Tekke monument

Survey of the Kioutouklou Baba Bekctashic Tekke monument

Finally, a number of distinct and visibly strong feature points on the surface of the monument were selected. These points had a random spatial distribution on the surface of the monument. A total of 33 points were measured using a Topcon GPT-3005 N total station. Finally, the empirical measurements session involved the measurement of short distances between several details on the surface of the monument. Again, a total of 10 distances between distinct points were captured.

CETI created a 3D digital replica the monuments exterior using the images captured and commercial 3D reconstruction software that is based on the Structure-from-Motion and Dense Multi-View 3D Reconstruction algorithms. CETI’s digitisation team evaluated the quality of the data produced by the software in relation to the data produced by the other digitisation methods. More about the quality results can be found in the following paper: A. Koutsoudis et al., Multi-image 3D reconstruction data evaluation, Journal of Cultural Heritage, Vol.15(1), pp.73-79.

A high definition video sequence of the monument’s 3D replica.