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Format of the products

Start at (azimuth) line 1, (range) pixel 1 (near range). Data is written line by line (major row order). We give the binary data a .raw extension.

The complex interferogram is written pixel interleaved (see D.2). Each complex pixel is written as 4 byte real, 4B imaginary part.

Table D.2: The way complex files (SLC data, resampled slave, complex interferogram) are stored on disk. Also refered to as mph format (magnitude phase). This is a major row order stored, pixel interleaved file with 2 (float 4B) canals (real,imag).
  1st pixel 2nd pixel ... pixel P
1st line Real,Imag Real,Imag ... Real,Imag
2nd line Real,Imag Real,Imag   ...
3rd line Real,Imag Real,Imag    
... ...      
line L Real,Imag Real,Imag ... Real,Imag

After unwrapping of the phase the result can no longer be stored as a complex value, because a complex number only can distinguish between phase values in the principal interval $ \pm\pi$. Therefor a new format is used/will be used. Either the unwrapped phase is simply stored in a 4B float file, similar to table D.2 without the imaginary part (as are other files, like the phi, lambda, and height matrices after geocoding), or a hgt file is generated (see table D.3.

Table D.3: Format of a hgt (height) file. (unwrapped complex interferogram and others) Actually is a major row order, band interleaved data, with 2 float (4B) canals (amplitude phase).
  1st pixel 2nd pixel ... 1st pixel 2nd pixel ...
1st line Amplitude Amplitude ... Phase Phase ...
2nd line Amplitude Amplitude   Phase Phase ...
3rd line Amplitude Amplitude   ...    
... ...          
line L Amplitude Amplitude ... Phase Phase ...

Particularly after unwrapping the conventions we use for this file are as follows. The amplitude (equal to that of complex intererogram) and the unwrapped phase is stored for each pixel. If there is no unwrapped phase, the wrapped phase is stored, and the amplitude is set to 0 for that pixel. (I would prefer setting the phase to 0, and keeping the amplitude, but we selected this format to keep in line with other software.) The amplitude is stored, while it does not change after unwrapping, to keep all information in one file.

Computations are done in general in the original master system. (no matter if cut-out or multilooked.)

Time system (orbit) is in seconds of day. Ephemerides orbit system is more or less WGS84.

Matrix class:
A matrix is starts at 0,0 etc.

Offset for a certain point is defined as: coordinate in slave system = coordinate in mastr system + offsets.

next up previous contents
Next: Matrix class Up: Definitions Previous: Orbit interpolation   Contents
Leijen 2009-04-14