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Input is the unwrapped topo-interferogram (corrected for 'flat earth'). Format is hgt, or real4. Not unwrapped thus indicated by NaN==-999. (real4) or if amplitude==0 (hgt). Defo-interferogram is wrapped (complex real4, mph) (specified in interferogram result file).

  1. Obtain orbit for topo-slave (result file). Obtain filename/dimension of unwrapped interferogram (result file).
  2. Read in matrices, appropriate size/format etc. per line. Check if they exactly overlap.
  3. Compute $ {B_{\perp}}$ and $ {B_{\perp}}'$ on a small grid (20x10 points over the image).
  4. Model the ratio of the perpendicular baselines by a 2D polynomial of degree 1. (r(l,p) = a00 + a10l + a01p) Give statistics for max. error due to modelling. (It seems the ratio hardly changes over the image for ERS1/2).
  5. Compute wrapped deformation phase (phase corrected for topography) with formula 31.17, using the modeled ratio $ r_{ij}$. (Actually compute it complex: $ c_{ij} *=
\cos(r_{ij}\cdot\phi) - i\sin(r_{ij}\cdot\phi)$.)
  6. Set not unwrapped regions to (0.,0.)
  7. Write output file (complex real4, mph format). (if a problem with unwrapping occurred, write (0,0).) If requested, also write the scaled unwrapped interferogram.

Leijen 2009-04-14