CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
Distributed Information Virtual Database Geo-Multimedia Applications 
Figure 2. ReGeo system (Frech & Koch, 2003) 
There is an ongoing research project funded by the European 
Union aiming at the development of a comprehensive online 
tourist information system of the Thuringian Forest area, 
based on a geo-multimedia database. The project ReGeo 
("Multimedia Geo-Information for E-Communities in Rural 
Areas with Eco-Tourism" - Freeh & Koch, 2003) offers 
tourists essential and useful information about their holiday 
region, but also supports local business and administrators 
(Fig. 2). 
The touristic infrastructure and sights can be explored by map- 
guided quests as well as by alphanumeric thematic search. For 
geographical visualization, 2D tourist maps, aerial images 
together with vector data as well as 3D models and 3D 
sceneries are provided. To generate a 3D model of Wartburg 
Castle being a highlight of touristic interest in the Thuringian 
Forest, photogrammetric data acquisition and 3D object 
reconstruction have been carried out. 
Examples of 3D modeling and visualizing architectural objects 
can be found in the literature related to photogrammetry, 
surveying as well as computer vision. The "photogrammetric 
way" including a detailed and precise 3D object reconstruction 
is explained, e.g., in Hanke & Oberschneider (2002), Daskalo- 
poulos et al. (2003), whilst computer vision techniques are 
emphasized, e.g., in Pollefeys et al. (2003), El-Hakim (2002). 
The different approaches have their advantages and 
limitations. This paper is intended to compare photo 
grammetric and computer vision methods for camera 
calibration and image orientation based on parts of the 
Wartburg data set. 
2. OBJECT RECORDING 
The Wartburg is built on the top of a rocky hill. The terrain 
slopes steeply away on all four sides of the castle complex. 
Access to the inner courtyards is possible solely via a small 
drawbridge. The outer facades of the Wartburg could be 
photographed from only few viewpoints. Images taken from an 
ultra-light airplane had to be added to get a sufficient ray 
intersection geometry for the photogrammetric point 
determination. The inner courtyards were successfully 
recorded from the two towers, some windows, and from the 
ground. Three image acquisition devices were used: The Rollei 
d30 metric 5 and Canon EOS D60 SLR cameras, and a Sony 
DCR-TRV738E camcorder (cf. Tab. 1 for tech, specifications). 
The 5 megapixel Rollei camera provides some features of a 
metric camera, such as fixed focal length and a rigid 
connection between lens and CCD chip inside the camera. In 
addition, two focusing stops can be fixed electronically, i.e., 
the interior orientation parameters at these two focus settings 
can be regarded as known over a period of time, if they were 
once determined by camera calibration. The d30 metric 5 used 
within the Wartburg project was calibrated for the focal length 
f, = 15 mm and f 2 = 30 mm. The setting f 2 was used for the 
images taken from the ultra-light airplane, whilst f ( was 
employed for all other images. The Canon EOS D60 providing 
a wide angle lens, 6 megapixel sensor and larger image size as 
the Rollei camera was used to record several parts of the 
courtyards which could be acquired only from a shorter 
distance. The camcorder served in addition to collect some 
overviews and short image sequences (movies) to be presented 
in the tourist information system. 
Rollei d30 metric 5 
Canon EOS D60 
Sony DCR-TRV738E 
Number of pixels 
2552 x 1920 
3072 x 2048 
720x 576 
Sensor format 
9 mm x 7 mm 
22 mm x 15 mm 
Lens (focal length) 
10 mm - 30 mm 
(= 40 mm - 120 mm 
for 35 mm camera) 
20 mm (SLR) 
( = 32 mm for 35 mm 
camera) 
3.6 mm - 54 mm 
( = 48 mm - 720 mm 
für 35 mm camera) 
Image data 
6.4 MB uncompressed 
raw data per image 
7.4 MB uncompressed 
raw data per image 
0.8 MB 
Table 1. Technical Specifications of the cameras used in the project