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There is an emerging interest for multi-sensor high resolution 
image data: combinations of active and passive images spanning 
the electromagnetic spectrum are likely to be used for thematic 
applications. In turn, the problem is to include methods from 
integrating multi-sensor data so that users gain an expanded 
knowledge of the scene content. 
Bearing in mind such a purpose, the instrumentation for SAR 
image processing has to be reviewed (production of so-called 
SAR precision products). 
The actual consequences are computerwise not trivial 
(e.g. required rotation of a very high resolution SAR image to 
get vertical north, use of accurate digital elevation models 
etc.) and its practical feasibility is not yet demonstrated. 
4. CRITICAL AREAS AND CONCLUSIONS 
The two WG.II.5 technical sessions during the Rio de Janeiro 
Congress will be devoted to update the previous considerations 
and finalise the findings and recommendations of the working 
group. 
However, and to conclude this report, we would like to suggest 
some areas which are felt today as critical and therefore which 
are likely concerns for the future activities. 
‚We see the necessity of developing practical activities along 
the following lines: 
- the ground preprocessing activities are now becoming 
processing activities: the SAR image is no longer the only 
product 
- as the instrumentation for SAR processing becomes 
computerwise extremely efficient, the possibility of 
developing precision products will have to be considered 
- in turn, these possible precision products require 
additional instrumentation (e.g. data banks including 
digital terrain models) 
- the ultimate goal is to consider SAR data as part of a 
multi-sensor approach. The required instrumentation is far 
from existing: validation and calibration of SAR data 
requires more than corner reflectors but a careful 
end-to-end system design and the development of specific 
items (e.g. active transponders for calibration) 
- simulation is an effective tool for approaching the 
information content of SAR data and therefore develop 
application oriented processing algorithms. However, it 
requires the setting up (on a long term basis) of radar dats 
bases