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Based on these resolutions and on final discussions during the meeting 
of the ISPRS Council and Commission Presidents in Zürich in November 
1988 the Intercommission Working Group II/III (IC WG II/III) "Design 
and algorithmic aspects of digital photogrammetric systems" was 
established. Prof. Dr.-Ing. H. Ebner and Dr. I. Dowman were invited to 
act as Chairman and Co-Chairman. Dipl.-Ing. C. Heipke was appointed 
secretary of the IC WG II/III. 
2. IC WG II/III deals with the following three topics: 
Topic 1 Definition of functionality and performance of digital 
photogrammetric systems. 
A digital photogrammetric system is defined as hardware and 
software to derive photogrammetric products from digital imagery 
using manual and automated technigues. The output from such 
systems may include object point coordinates, reconstructed 
surfaces, extracted features or orthoimages. 
The design aspects include system architecture and components, 
interfaces to data capture, data output and geographical 
information systems (GIS) and the human interface. 
The algorithmic aspects are related to on-line and real-time 
procedures, restitution modes such as mono, stereo, multi image 
and parallel processing. 3 
Topic 2 Critical evaluation of systems existing so far. 
The existing digital photogrammetric systems can be divided into 
two main groups: the general purpose stereo systems for directly 4 
recorded digital images or digitized aerial photographs and near 
real-time systems for close range work. 
The reguirements for data storage and data manipulation are 
greater in the first case. These systems have mainly been produced 
by large manufacturers. Examples are the Kern DSP1, the Topcon PI- 
1000, the Matra Traster T10, the Terragon Context Mapper, the 
Autometrics Pegasus, and the DVP Digital Video Plotter of Laval 
University. 
In the second category speed is the most important issue, but the 
complexity of the image content and the data volumes are lower. 
The development of these systems has mainly been carried out for 5 
special applications by research establishments like ETH Zurich, 
University of Cape Town, National Research Council, Winnipeg, and 
Helsinki University of Technology. 
Further instruments without continuous stereo viewing have been 
reported e.g. from Helava Associates and from University College 
London. 
A comparison of the different systems in terms of cost and perfor 
mance has still to be undertaken.