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remotely perform automatic face recognition. The user will then 
instantly receive details of the person, if a match is found. The 
system can be useful especially for the instant face 
identification and authentication tasks. Clemens et al. (2005) 
develop a panoramic image application suit for handy cameras. 
The image stitching is carried out in real-time. Pittore et al. 
(2005) implement an image-based context awareness engine 
specifically for archeological sites and museums. Visitors can 
“ask” information about an unknown monument by simply 
taking a picture of it with a camera integrated mobile phone and 
send it to the system for recognition. Ueda et al. (2004) use 
mobile phones, equipped with a camera and a GPS chip, as a 
content provider to a Geographical Information System (GIS). 
Users can annotate objects in the environment by sending text, 
picture and location information via mobile phone to a central 
data base. Chung et al. (2004) correct the radial lens distortion 
of a mobile phone camera applying a calibration procedure 
from Lenz and Tsai (1988). However, their experiment lacks 
numerical results and analysis. In spite of the availability of a 
broad diversity of applications, the metric capabilities and 
characteristics of mobile phone cameras have not been 
investigated so far. 
In 2004, Sharp Corporation developed a 2 Mpixel CCD camera 
module with 2X optical zoom and auto-focus function (Figure 
la) intended for use in mobile phones (Physorg, 2004). In 2005, 
they released two new camera modules (Figure lb) with a 3 
Mpixel CCD chip (Physorg, 2005). One year after, Samsung 
announced a 10 Mpixel camera phone (Figure lc) at CeBIT 
exhibition in Hannover (Williams, 2006). These examples show 
the rapid progress in the technology of mobile phone cameras. 
Due to very limited size and restricted material and equipment 
costs, the production of mobile phone cameras is a challenge 
(Myung-Jin, 2005; Chowdhury et al., 2005). The impact of their 
production specifications on the stability of interior orientation 
and 3D object reconstruction capabilities has not adequately 
been studied yet. This work investigates the accuracy potential 
of two recent mobile phone cameras (Sony Ericsson K750i and 
Nokia N93) and compares them with respect to two off-the- 
shelf digital still video cameras (Sony DSC W100 and Sony 
DSC F828). The next chapter introduces the cameras and the 
calibration/validation testfield. We carry out self-calibration, 
accuracy testing, JPEG testing and stability testing of the 
interior orientation over time, and report the results in the third 
chapter. We present a comparative analysis of the results in the 
fourth chapter. 
2. CAMERAS AND THE TESTFIELD 
2.1 Cameras 
Four cameras are used (Figure 2). Two of them are mobile 
phone cameras (Sony Ericsson K750i and Nokia N93) and two 
of them are off-the-shelf digital still video cameras (Sony DSC 
W100 and Sony DSC F828). The mobile phone cameras have 
CMOS sensors of smaller size than the CCD chips in the off- 
the-shelf cameras and partly much smaller lenses. The technical 
specifications of all four cameras are given in Table 1. 
2.2 Testfield 
The photogrammetric calibration field at the Institute of 
Geodesy and Photogrammetry (HIL C57.3, ETH Zurich) was 
used. It is 3.4 x 2.0 x 1.0 m 3 in size. The 3D coordinates of 87 
well distributed control points (GCP) were measured using a 
Leica Axyz system. The Leica Axyz system consists of two 
Leica total stations (TC 3000 and TC 2002) and one processing 
computer unit, which is connected to them (Figure 3). After an 
initialization step, two operators simultaneously measure the 
vertical angles and horizontal directions of the targeted point. 
The system calculates the 3D coordinates (by spatial 
intersection) and the precision values in real-time. The scale of 
the object space was given by measuring a bar whose length 
was accurately defined by interferometry as 1000.051 ±0.010 
mm. The average theoretical precision values of the GCPs are 
±0.03, ±0.05 and ±0.03 mm for X, Y and Z axes, respectively. 
Figure 2. Cameras used in our tests: (a) Sony Ericsson K750i, (b) Nokia N93, (c) Sony DSC W100, (d) Sony DSC F828. 
K750i 
N93 
W100 
F828 
Sensor 
CMOS 
CMOS 
CCD 
CCD 
1/3.2” = 4.5 x 3.4 mm 
1/3.2” = 4.5 x 3.4 mm 
1/1.8” = 7.2 x 5.3 mm 
2/3” = 8.8 x 6.6 mm 
Pixel size 
2.8 micron 
2.2 micron 
2.2 micron 
2.7 micron 
Image format 
1632x 1224 
2048x1536 
3264 x 2448 
3264 x 2448 
2 Mpixel 
3.2 Mpixel 
8 Mpixel 
8 Mpixel 
Lens 
No information 
Carl Zeiss 
Carl Zeiss 
Carl Zeiss T* 
Vario-Tessar 
Vario-Tessar 
Vario-Sonnar 
Focal length 
4.8 mm 
4.5 - 12.4 mm 
7.9 - 23.7 mm 
7.1 - 51.0 mm 
Optical zoom 
No 
3X 
3X 
7X 
Auto focus 
Yes 
Yes 
Yes 
Yes 
Aperture 
F/2.8 (fixed) 
F/3.3 (fixed) 
F/2.8 - F/5.2 
F/2.0 - F/8.0 
Output format 
Only JPEG 
Only JPEG 
Only JPEG 
JPEG and TIFF 
Table 1. Technical specifications of the cameras.