Tuesday, January 21, 2014

Importance of applying SAR terrain correction

There are still many publications with SAR images which are not terrain corrected. In SAR images there is a displacement of the pixel dependent on its elevation. A few years ago, applying terrain correction was a major task, but the NEST Toolbox allows that to be done very easily by anyone (see the four post describing this here )

A very good example on the importance of applying terrain correction I had just today. The following image was geocoded simply using gdalwarp as explained in previous post.. It shows displacement for a vehicle  track visible on the SAR image in the snow compared to its true location Note that the track is displaced the same direction as the SAR layover of the mountain:



Applying Range Doppler terrain correction using NEST and a not very perfect DEM, the track matches much better:



(Subset of Antarctis Radarsat-2 image, provided by NSC/KSAT under the Norwegian-Canadian Radarsat agreement 2013)

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