The DEM-assisted coregistration is estimated in two steps:
First, the DEM is radarcoded to the coordinate systems of the master and slave image. Per DEM point the master coordinate and the offset between master and slave is saved to a file. Both the master coordinates and offsets are real valued.
Second, the offsets are interpolated to the integer grid of master
coordinates. A linear interpolation based on a Delaunay triangulation
is used. The software package Triangle for the Delaunay
triangulation is kindly made available by Jonathan Shewchuk
[16,17], see also
The finally optained master-slave offsets per master pixel are saved
to a file and used in the RESAMPLE step to resample the slave
image to the master geometry.