Proceedings 18 th International Symposium CIPA 2001 
Potsdam (Germany), September 18 - 21, 2001 
IMAGE ACQUISITION FOR DIGITAL PHOTOGRAMMETRY 
USING „OFF THE SHELF“ AND METRIC CAMERAS 
Günter Pomaska 
FH Bielefeld, University of Applied Sciences 
Artilleriestr. 9, D32427 Minden 
gp@imagefact.de, www.imagefact.de 
KEY WORDS: Camera Calibration, Lens Distortion, Image Deformation, Image Refinement, Image Co-ordinates, Object 
Resolution 
ABSTRACT 
Photogrammetric recordings in fields like architecture or archaeology have to be taken in a rapid and easy manner. Therefore and 
under consideration of processing the images for getting data formats for interactive Web publishing, VRML or 02C for example, an 
overview about utilizing „of the shelf 4 cameras for dimensional analysis from photos is given. 
Most of the photo evaluation processes need the definition of an image co-ordinate system due to the mathematical model that is 
assumed as central projection. Model deviations should be parameterised and corrected. A major influence is provided by the interior 
orientation, the camera parameters. The position of the principle point and the amount of lens distortion should be known. 
Insufficient film flatness or in general image deformation is important while using lager format and film scanning. 
Typical device attributes like format, film or digital, SLR or viewfinder classify the cameras. It is not possible to cover the whole 
range of good camera equipment available. The cameras introduced here are representatives for their category. 
Camera calibration strategies and procedures are described from a practical point of view. Results from desktop image evaluation 
software will be discussed. 
1. DIGITAL IMAGE ACQUISITION 
More or less any camera is suitable for photogrammetric applications. A camera can be used as a metric one if the position of the 
projection centre relatively to the image co-ordinate reference system is known and if the amount of lens distortion can be corrected. 
Film flatness in case of larger formats could be a problem of accuracy. Following a short overview about analogous film cameras, 
digital cameras and metric cameras is given. It is not possible to cover all the products complete. Only equipment with special 
features is mentioned here. CIPA Working Group VII provides on its Web site a collection of cameras with more technical details, 
(CIPA WG VII 2001). 
1.1 Analogous film cameras 
35mm cameras are available as SLR types or equipped with a viewfinder. The wide range of lenses from 8 mm fisheye, 16mm or 
22mm wide angle up to long focal length lenses of 500 mm provide solutions in extreme situations. A sample is given with the 8mm 
fisheye configuration and the spherical panorama calculated from two of those images, see figure 1. The newer APS film format is 
not recommended for metric applications since there are no benefits to detect. Image formats in the range of 60mm x 60mm are 
known as medium format cameras. Hasselblad, Pentax or Rollei for example are vendors of professional equipment. The here 
mentioned brands all provide modified solutions as metric versions using a réseau or vacuum for film flattening. Larger formats for 
landscape photography are for example the Mamiya 711, a 6x7 cm format viewfinder camera or the Fuji GX617 panorama camera 
with an image format of 60x170mm. For the Mamiya a 4,5/50mm wide-angle lens is available in comparison to a 35 mm format this 
equals a 24 mm focal length. The image angle covers 84 degree. It is important to compare the focal length of a lens in respect to the 
image format or to focus on the image angle. 
1.2 Digital cameras 
Digital cameras are still in a rapid changing development process. Their suitability for metric applications is not a question. Image 
format and resolution should be reviewed critical particular for architectural applications. One can group the types of digital cameras 
today into mega pixel cameras, 35 mm SLR cameras and digital data backs for medium formats. 
The Kodak DCS 290 is one of the low cost mega pixel cameras. A Matshushita MN39570PT sensor comes in its physical size of 
7,56*4,8 mm with a resolution of 1800 xl200 pixel. The aspect ratio of 3:2 is the same as for a 35mm film. Pixel size is 4.2 microns. 
Adopting RGB Bayer arrangement in colour filter array provides colour reproduction; see (G. Pomaska, 1999). Setting the zoom lens 
to one of the predefined positions and fixing the focus enables camera calibration. A calibration sample for the 35 mm focal length at 
infinity shows radial symmetric lens distortion of about maximum 0.030 mm.