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DIGITAL LOW-COST REMOTE SENSING WITH PFIFF, THE INTEGRATED DIGITAL 
REMOTE SENSING SYSTEM 
G. J. Grenzdórffer* 
Rostock University, Institute for Geodesy and Geolnformatics, J.-v.-Liebig Weg 6, 18059 Rostock, Germany — 
goerres.grenzdoerffer@auf.uni-rostock.de 
KEY WORDS: digital airborne imaging systems, direct georeferencing, automated aerotriangulation 
ABSTRACT: 
Beside high end digital imaging systems which will replace standard photogrammetric cameras in the future, a large number of “low- 
cost” airborne systems were developed in the last years. The system PFIFF, a digital airborne remote sensing system developed by 
the author, is described in detail with special respect to demonstrate the photogrammetric potential of PFIFF. The demand for current 
digital data of “hot spots” for various purposes is strongly increasing. in the last years several digital airborne systems were 
deve 
loped in the research community and for commercial use to fulfil this demand. A categorization in terms of their main 
components and their generated products is given. The system PFIFF, a digital airborne remote sensing system, developed by the 
author, is described in detail with special respect to the demands and problems of high resolution urban surveys. 
1. INTRODUCTION 
Urban areas undergo a continuous change; this change however 
doesn’t take place in the whole town, but in certain developing 
areas such as construction sites etc. These areas are often 
relatively small; let’s say only a few km? The user, especially 
local agencies, developers and private companies are interested 
in current data of these “developing spots” with a high level of 
detail. They also want the data to be delivered digitally and 
orthorectified within a few days after an aerial survey. The cost 
for data per km? from a conventional aerial survey however 
increases, the smaller the area of interest becomes. Due to these 
reasons there is a strong demand for economically priced 
remote sensing data for small areas. 
The introduction of the high end digital imaging systems which 
shall replace the standard photogrammetric cameras is a slow 
process, why? Digital systems like the DMC, ADS 40 or 
Ultracam are on the market and technically well developed. But 
especially for smaller airborne companies a beneficial operation 
is hard to find, because of the high system price. On the other 
hand digital “low-cost” systems which provide an cfficient and 
fully digital work flow from image acquisition to orthophotos 
and digital terrain models are booming. The focus of small 
digital imaging systems are either new markets such a precision 
farming or they displace the standard photogrammetric camera, 
e.g. to obtain additional image data during laser scanning. In 
general digital low cost systems may be better suited than 
standard photogrammetric camera in the following fields: 
- Lower price per mapped area, especially for small sites of a 
few km? or with low ground resolution 
- Short turn around time from image acquisition to the first 
image / final product due to an automated and fully digital 
work flow 
- Combination of nadir an oblique viewing images. 
In the last years many digital airborne "low-cost" systems were 
developed in the research community world wide for a large 
range of applications and with different technical specifications, 
e.g. Báumker et al, 1999, Franke and Montgomery, 2000, Holm 
and Rautakorpi, 1999, Mostafa and Schwarz, 2000, Thom and 
235 
Souchon, 1999, Toth, 1999. There are also integrated 
commercial systems available, e.g. ADAR from Positive 
: TM & 
Systems or EM ERGE™ from Emerge or Leica to name only 
two. 
These systems range from “low end” systems for the acquisition 
of single or multiple vertical images to professional high end 
systems with fully automated photogrammetric workflow and 
direct georeferencing of single images, image strips or blocks. 
There are certain key components necessary, e.g. an advanced 
flight management system or a GPS/INS to enhance the degree 
of automation to produce orthoimages and digital surface 
models. 
The efficiency of a digital system in terms data acquisition, data 
processing, turn around time and price for the user is always a 
compromise. With the use of more sophisticated technologies 
the photo flight and the orthorectification process may be speed 
up significantly. On the other side the cost for such a system 
raises drastically, thus requiring large areas / huge amounts of 
data to be processed. 
In the following the system components of PFIFF a digital 
airborne system developed by the author will be described and 
some experiences with aerial surveys and direct georeferencing 
will be presented. 
2. PFIFF 
PFIFF, a digital airborne remote sensing system, was originally 
developed by the author to fulfil the special requirements of 
precision farming. Those requirements — low cost, high amount 
of detail and rapid delivery — are very similar to those urban 
users. 
2.1 System components of PFIFF 
The core of the system is a digital SLR colour camera, the 
Rollei db23. The CCD-sensor from Phase One has a resolution 
of 2032 * 3056 pixels, see Table 1 for the technical details of 
the camera. With the exposure interval of less than 2 seconds,