The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008 
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software the user can also minimise remaining vignetting and 
lens aperture effects which may occur at low f-stops. 
Radiometric problems of the medium format cameras are 
related to several issues. 
• The radiometric postprocessing of the raw imagery, which 
come in a black box raw format is generally done in a 
software environment primarily developed for non 
photogrammetric users, but for professional photographers. 
Therefore issues such as radiometric linearity, atmospheric 
correction etc. are not a primary issue. 
• There is no single standard algorithm for converting data 
from a Bayer filter or Foveon sensor into RGB format. 
• the color infrared option causes longitudinal chromatic 
aberrations. Due to the strong sensitivity of the CCD-chip in 
the IR-light the resulting image is more or less a reddish 
coloured IR-image, Grenzdorffer, 2006 
• In the postprocessing of the raw images after the flight the 
images may be corrected and manipulated with respect to: 
• a colour balancing due to the atmospheric conditions 
• general visual expectations of the users (e.g. grass has 
to be green) 
• vignetting and influence of aperture 
• histogram enhancements for 16 bit —► 8 bit conversion 
• image sharpening and noise reduction. 
• the degree of the radiometric postprocessing and the 
resulting colors are solely subject to the visual 
impression of the interpreter, and 
• proposed radiometric corrections steps (e.g. Honkavaara 
& Merkelin, 2007) and quality measures are difficult to 
obtain. 
5. STANDARDISATION 
Standardisation for aerial cameras and the photogrammetric 
processing chain is taking place at several levels, from ISO 
down to national initiatives. However most of the 
standardisation effort is related to large format cameras, thus 
sometimes neglecting and more or less excluding medium 
format cameras. In other instances the standardisation is very 
general and in general not of great practical use. 
In Germany the standard series DIN 18740 - Photogrammetric 
Products (Part 1 - 4) covers especially large format cameras, 
Reulke et al., 2007, DIN 2007. Part 4, finalised in Sept. 2007 
deals with the requirements for digital aerial cameras and 
digital aerial photographs. Focus is given to digital aerial 
cameras, aerial survey flights and the digital aerial photograph. 
For digital aerial cameras the standardisation provides quality 
measures on: general requirements of the camera and its 
components, camera calibration (geometry and radiometry) and 
requirements of sensors for positioning and attitude 
determination. The geometric quality related to the image 
product has to be documented in a manufacturer certificate, in 
which the camera system and its subsystems have to be 
geometrically and radiometrically calibrated. The validity of 
geometrical calibration at the time of flight has to be proven by 
validation test (less than one year ago) or new calibration (less 
than two years ago), DIN 2007. 
Due to the fact that digital aerial systems are more than just 
cameras and the final quality is not only related to the sensor 
standards should not only focus on the certification of the 
cameras itself but include the whole end-to-end processing 
chain. Based on these facts the USGS has formulated a different 
approach. Individual cameras are not the subject of certification, 
but a “type certification”, Stensaas, 2007. With this approach it 
should be ensured that the sensors are designed, built and tested 
to reliably deliver data with a high quality. However this is only 
true if the operating company operates and maintains the 
system properly. Currently the DSS 439 is the only medium 
format camera system certified by the USGS. 
6. APPLICATION DOMAINS 
From an application standpoint, it is safe to say that medium 
format digital cameras are not their large format cousins, but 
rather a niche market solution for specific project types. The 
largest proportion of medium format cameras are used as a sub 
system of integrated airborne data acquisition platforms 
consisting of laser scanners (LIDAR) combined with imaging 
Laserscanning & Camera 
• Mapping & Orthophotos 
• True Orthophotos 
• 3D-City Models 
Strip Mapping 
• Linear-based mapping projects 
• Pipeline surveys 
• Hydro corridors 
• Transportation routes 
Rapid Response Imaging 
• Rapid mobilisation for disaster management 
• Time-dependent image acquisition 
• Homeland Security digital imaging 
Agriculture and Forestry 
• Species identification 
• Timber value assessment 
• Disease control and monitoring 
• Precision Farming 
GIS and Urban applications 
• Urban and regional planning 
• Urban Hot-Spot Monitoring 
• 3D-Models (Nadir + Oblique) 
Remote Sensing 
• Environmental research 
• Coastal zone monitoring 
• Colour-Infrared imaging 
component and GPS/inertial sensors for direct platform 
orientation. Such integrated airborne systems are operated by 
many airborne companies. A special requirement for joint laser 
surveys is an extremely high light sensitivity and a fast shutter 
speed, Artés, 2004. Another more or less exclusive market for 
medium format cameras are mapping small, irregular shaped 
areas, strip mapping, transmission line corridors or pipeline 
contracts, which do not always require the ground coverage 
produced with a large format camera. A direct georeferencing 
capability with GPS/INS is in these instances a tremendous 
advantage because it allows for a greater degree of freedom in 
the aerial survey, such as a strip map coverage where a single 
line imagery can be utilised without the need for a second flight 
line, and small blocks can be easily georeferenced to produce 
orthophoto mosaics. Direct georeferencing enables “hot spot”