DETERMINATION OF GEOMETRIC CHARACTERISTICS 
OF A DIGITAL CAMERA BY SELF-CALIBRATION 
H.El-Habrouk, X.P.Li, W.Faig 
Department of Geodesy and Geomatics Engineering 
University of New Brunswick 
Fredericton, New Brunswick 
Canada, E3B 5A3 
Commission I, Working Group 3 
KEY WORDS: Digital Camera, Geometric Characteristics, Self-Calibration 
ABSTRACT 
Digital cameras are being used in a wide range of industrial and engineering applications. To achieve highly accurate and 
precise results, the digital cameras have to be calibrated for both their geometric and radiometric characteristics. Generally, 
the geometric calibration is conducted with the aid of some special digital image processing software. Often however, the 
available software is cumbersome or unsuitable for certain industrial applications. 
This paper illustrates the use of a well-established self-calibration procedure for the determination of the geometric 
characteristics of a Fujix DS-100 digital camera. 
Based on the results of this study, a self-calibrating bundle adjustment in conjunction with basic digital image processing 
provides an excellent solution to the geometric calibration of digital cameras. 
KURZFASSUNG 
Zahlreiche Anwendungen der Industrie-und Ingenieurphotogrammetrie benützen digitale Kameras, welche für höhere 
Genauigkeitsansprüche radiometrisch und geometrisch kalibriert werden müssen. 
Es gibt spezielle Bildverarbeitungsprogramme für die geometrische Kalibrierung, jedoch sind diese oft umständlich und 
ungeeignet für bestimmte Projekte. 
In diesem Artikel wird die Anwendung eines bekannten Selbstkalibrierungsverfahren für die Bestimmung der geometrischen 
Parameter der Fujix DS-100 beschrieben. 
Die Ergebnisse zeigen, dass einfache digitale Bildverarbeitung mit selbstkalibrierender Bündelausgleichung für die geometrische 
Kalibrierung digitaler Kameras gut geeignet ist. 
|. INTRODUCTION not always available for certain organizations or applications. 
Photogrammetry is at present in the process of a radicai Self-calibration methods have demonstrated their important 
transition from hard copy imagery to digital imagery. Digital role in analytical photogrammetry during the past several 
imagery possesses many advantages over their traditional decades. This type of method can efficiently model most 
analogue counterpart and thus is gradually being utilized in systematic errors of the imaging system. 
numerous applications. 
This paper describes a research project conducted at the 
High accuracy and precision are often demanded for certain Department of Geodesy and Geomatics Engineering at the 
industrial applications. This requires high geometric and University of New Brunswick (Canada). Its goal was to 
radiometric fidelity of the digital imagery, which in turn investigate the feasibility and the performance of a well 
demands solid construction and calibration of the established self-calibration procedure for the determination of 
imaging equipment, i.e. the digital camera. Once the the geometric characteristics of an off-the-shelf digital 
appropriate type of digital camera according to the camera. Two simple test models were prepared for this 
requirements and preference has been selected by the users, project. 
the calibration task becomes prominent when trying to obtain 
accurate results for the applications. 
2. SELF-CALIBRATION 
The objective of digital camera calibration is to exploit the 
high accuracy potential of digital photogrammetry by 2.1 Theoretical Background 
modelling and compensating for the systematic errors due to 
the lens, solid state sensors, etc. It usually includes two Self-calibration means that the interior geometric quantities of 
aspects, namely, geometric calibration and radiometric a camera (e.g., calibrated principal distance, principal point, 
calibration. For some of the digital cameras, the geometric lens distortion parameters, etc.) can be determined based on 
characteristics have been thought as the main factors which the relationship of two or more overlapping photographs 
have a negative influence upon the quality of the digital without additional control requirements. It has found wide 
imagery. Generally, the geometric calibration of the digital applications in aerotriangulation and industrial close-range 
camera is implemented based on special sophisticated digital photogrammetry. Usually, certain additional parameters (APs) 
image processing software and relevant hardware, which are ^ are included to model the systematic errors of the imaging 
60 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B1. Vienna 1996 
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