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METRIC ACCURAC TESTING WITH MOBILE PHONE CAMERAS 
Armin Gruen, Devrim Akca * 
Institute of Geodesy and Photogrammetry, ETH Zurich, CH-8093 Zurich, Switzerland - (agruen, 
akca)@geod.baug.ethz.ch 
Commission V, WG-V-5 
KEY WORDS: Mobile phone cameras, Self-calibration, Accuracy potential, JPEG test, Stability test. 
ABSTRACT: 
This paper examines the potential of mobile phones to be used as a front-end sensor for photogrammetric procedures and 
applications. For this purpose we are calibrating two mobile phones (Sony Ericsson K750i and Nokia N93) over our indoor 3D 
testfield, using self-calibration. Using the same testfield we are performing accuracy tests in order to evaluate the metric 
performance and comparing them with respect to two off-the-shelf digital still video cameras (Sony DSC W100 and Sony DSC 
F828). In some systems we have diagnosed substantial systematic errors. We find that the JPEG compression does not significantly 
influence the errors. We are currently also in the process of checking the stability of the interior orientation over time. This paper 
reports about our experiences in calibration and accuracy validation of mobile phone cameras. We believe that with a proper 
performance these devices can be used for many photogrammetric tasks in the future. 
1. INTRODUCTION 
Mobile Mapping has been an issue for ISPRS already for some 
years. Through the use of moving platforms (satellites, aerial, 
terrestrial) photogrammetry had from early times on a “mobile” 
component. Also, on-line and real-time processing is by no 
means new. However, with the availability of very affordable 
and good resolution CCD/CMOS cameras and other off-the- 
shelf devices, including compact computers (of laptop type) the 
potential of building efficient mobile systems has dramatically 
increased. On other occasions we have already reported on the 
use of an autonomous model helicopter for 3D modeling in 
different projects. Location-based services and ubiquitous 
computing are current busswords of high societal visibility and 
relevance. Among various hardware and software components 
mobile phones constitute an interesting component for image 
data acquisition for obvious reasons: They are very inexpensive, 
light and handy and have CMOS cameras of currently up to 10 
Mpixels image format. This paper examines the potential of 
mobile phones to be used as a front-end sensor for 
photogrammetric procedures and applications. 
Laptops do have nowadays so much processing power and 
storage capabilities that part of the model generation can be 
done in the field already. With available know-how and 
software modules in sequential estimation, semi-automated and 
automated triangulation and surface model generation and 
texturing, a good basis exists to build a system for mobile, 
field-based primary data acquisition and model building. We 
anticipate the (future) possibilities of on-line processing the 
acquired image data by mobile phone cameras. This opens the 
path for a paradigm shift from “Mobile Mapping” to “Mobile 
3D Modeling”. 
Usability of mobile phone cameras for many applications has 
recently been realized. One of the most prominent applications 
is the character/text recognition in a flexible and portable 
fashion (Watanabe et al., 2003; Koga et al., 2005; Parikh, 2005). 
Rohs (2004) realizes a scenario where camera phones are used 
to recognize the visual codes in the scene. By recognizing a 
code tag, the device determines the code value, the targeted 
object or image element. The phone’s wireless communication 
channel is used to retrieve online content related to the selected 
image area or to trigger actions based on the sensed code. 
Figure 1. (a) Sharp’s 2 Mpixel CCD camera module 
LZP0P3738, (b) Sharp’s 3 Mpixel CCD camera modules 
LZ0P3751 and LZ0P3758, (c) Samsung’s 10 Mpixel camera 
integrated handy SCH-B600. 
As a facial animation study for mobile phones, Riegel (2005) 
creates a specific 2D head model using the generic 3D MPEG-4 
face and portrait images. The model is animated via voice or 
text. Al-Baker et al. (2005) uses a GPRS and WAP enabled 
PDA or mobile phone for human face identification. The 
system allows the user to send an image of a human face, 
acquired through a mobile phone with a built-in camera, to 
* Corresponding author, www.photogrammetry.ethz.ch