International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004 
  
Byzantine Lycia, a Japanese joint research project whose 
members include art historians, archaeologists, architectural 
historians, a photographer, and students. They started 
excavating Church III, one of the four basilicas on the island, in 
1995 after several years dedicated to surface exploration. Over 
10 years of research has revealed that the city was built in the 
late 5th to early 6th centuries, i.e., during the early Byzantine 
era, and the close relationship between the island and St. 
Nicholas (Tsuji, 1995; Research Group for Byzantine Lycia, 
1998; 2002). 
Of the four basilicas on the island, the so-called Church II and 
Church III have kept their original form relatively well and 
hence they were selected as the first targets for 3D recording 
and modelling in the Gemiler Island project (Kadobayashi et al. 
2003). Church II, which stands halfway up the western slope of 
the island, has three aisles and measures about 20 x 10 x 9 m. 
The semi-dome of the apse and the north wall are well 
preserved (Figure 1). Some frescos remain on the walls around 
the entrance and the windows. A floor mosaic was also found 
there. 
  
Figure 1. Church II: exterior view (left) and interior view 
(right) 
Church III, located just below the top of the island, and hence 
easily visible to ships sailing on the Mediterranean, has three 
aisles and measures approximately 30 x 15 x 9 m. Generally, 
the south and west of the basilica, i.e. the atrium and west and 
south wall, are well preserved, whereas the north and east, i.e., 
the semi-dome of the apse and the east wall, are not. The 
wooden roofs of both basilicas have completely perished 
(Figure 2). 
  
Figure 2. Church III: west wall and nave (left) and apse and 
nave (right) 
3. DATA COLLECTION 
In 2002, we conducted 3D measurement of the two basilicas. In 
addition to the laser scanning, which was the main task, 
surveying using a total station and RTK-GPS, and taking 
photographs with digital cameras were carried out 
(Kadobayashi et al. 2003). In total, we spent 11 days at the site. 
3.1 Laser Scanning 
We selected a Riegl LPM-25HA to scan the two basilicas due to 
its battery-driven capability, portability, and accuracy in 
meeting our requirements. Although the basilicas are relatively 
large, the architectural historian required a sampling step of 1 
cm or less, assuming that the plans would have been drawn to a 
scale of 1:100. Table 1 summarizes the specification of the laser 
scanner. 
  
  
  
  
  
SPECIFICATION VALUE 
Measurement range 2 — 60m 
Measurement accuracy + 8 mm 
Measurement rate 1000 points/sec. 
Measurement resolution 1 mm 
  
Measuring beam diameter | 15 mm @ 10 m 
20 mm @ 20 m 
60 mm @ 60 m 
Laser wavelength near infrared 
Horizontal scanning range | + 180° 
  
  
  
  
  
  
  
Vertical scanning range =150° 
Positioning accuracy = 0.009" 
Angle readout accuracy + 0.009° 
Scanning speed 36°/sec. 
Scanner size 25 x 30 x 42 em 
  
  
  
  
Scanner weight 9.5 kg 
  
Table 1. LPM25HA laser scanner specifications 
We located the scanner at 29 points and scanned 55 images of 
Church III. The number of measured points was approximately 
34 million and the total data amounted to about 470 MB 
including the RGB value of each point. At Church II, we 
located the scanner at five locations and scanned seven images, 
totaling about 5 million points and amounting to 70 MB. It took 
about 55 hours to scan Church III and 7 hours to scan Church II. 
The sampling step was altered from 0.06 te 0.15 gon according 
to the importance and condition of the target, though due to 
limited work time, most targets were scanned with a sampling 
step of 0.1 gon. When the sampling step was 0.06 gon and the 
target was 10 m away, the sampling step on the target was 
about 1 cm, while it was about 1.6 cm when the sampling step 
was 0.1 gon. 
3.2 Photo Shoot 
The Riegl LPM-25HA is capable of capturing RGB color, but it 
was considered unlikely that the quality would be good enough 
for our applications. In addition, it was not able to scan the 
details of the mosaic flooring and hence we needed another 
method to record these. 
A DCS Pro Back from Kodak with a Distagon 50-mm F4 FLE 
lens, mounted on.a Hasselblad 555ELD, was used to record 
high-resolution images that were intended to be used to provide 
texture data for the 3D models. It has a CCD that is 36.86 x 
36.86 mm and produces 4072 x 4072 pixel images. Around 
1300 images were taken at Church II and Church III. 
We took these photos in such a way that adjacent pictures 
would overlap. As far as possible, we also tried to take them 
from an orthogonal position in relation to targets such as walls, 
though this was sometimes impossible when photographing 
floors since scaffolding was required. In these cases, 
   
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