4 Final Report - Emits - ESA

3 Final
Report
• Image post integration and Inter-channel co-registration
If motion compensation on-board is required, several options are feasible:
− 1. Post-integration with respect to the first frame of each channel on-board and interchannel
co-registration based on landmarks on ground. Major drawback are successive
processing steps involving resampling.
− 2. Post-integration with respect to the first frame of the all channels on-board.
Advantageous is the avoidance of multiple resampling, however it is necessary to
perform image matching between different spectral channels which might lead to a
somewhat reduced matching performance. No inter-channel co-registration processing by
landmarks has to be performed on-ground.
− 3. Read-out of the panchro channel simultaneous to the first frame of each channel.
Post-integration will be performed as for option 1. The panchro channels will provide due
to their high resolution high matching accuracy regarding image motion compensation.
− 4. Read-out of the panchro channel simultaneous to each frame of each channel. Postintegration
and inter-channel co-registration are performed on-board with respect to the
first panchro image acquired. Resampling is therefore applied only once. This would lead
to the best performance for both image motion compensation and inter-channel coregistration.
The choice for one of these options depend highly on the processing capabilities available
on-board. The currently proposed baseline is a motion compensation on-board using only
integer pixel shifts (due to lower processing power), which would not meet the inter-channel
co-registration requirements. Therefore, the inter-channel co-registration processing is based
on landmark processing on-ground.
3.3 Mission Scenarios
The main focus for the analysis of the Geo-Oculus mission scenarios is the combination of a back
ground marine application mission with high coverage needs (European coastlines) and fast revisit
emergency missions. Both kind of missions have to some extend contrary mission requirements (e.g.
need of large FoV for marine and high resolution, combined with high revisit for the emergency
missions.
A balancing between effective (cloudfree) coverage for the marine application mission and number of
emergency missions has to be performed. This depends on:
• cloud coverage statistics;
• importance of emergency missions.
The following diagram shows the correlation between effective coverage and number of emergency
missions schematically. For precise numbers, a detailed cloud coverage analysis would be needed.
Page 3-18 Doc. No: GOC-ASG-RP-002
Issue: 2
Astrium GmbH Date: 13.05.2009