Gives, for each pixel, the power that would have been received by a SAR system with a basis different from the classical (H,V) one (polarimetric synthetis).
This application gives, for each pixel, the power that would have been received by a SAR system with a
basis different from the classical (H,V) one (polarimetric synthetis).
The new basis A and B are indicated through two Jones vectors, defined by the user thanks to orientation
(psi) and ellipticity (khi) parameters.
These parameters are namely psii, khii, psir and khir. The suffixes (i) and (r) refer to the transmiting antenna
and the receiving antenna respectively.
Orientations and ellipticities are given in degrees, and are between -90°/90° and -45°/45°
respectively.
Four polarization architectures can be processed :
1) HH_HV_VH_VV : full polarization, general bistatic case.
2) HH_HV_VV or HH_VH_VV : full polarization, monostatic case (transmitter and receiver are
co-located).
3) HH_HV : dual polarization.
4) VH_VV : dual polarization.
The application takes a complex vector image as input, where each band correspond to a particular
emission/reception polarization scheme.
User must comply with the band order given above, since the bands are used to build the Sinclair
matrix.
In order to determine the architecture, the application first relies on the number of bands of the input
image.
1) Architecture HH_HV_VH_VV is the only one with four bands, there is no possible confusion.
2) Concerning HH_HV_VV and HH_VH_VV architectures, both correspond to a three channels image.
But they are processed in the same way, as the Sinclair matrix is symetric in the monostatic
case.
3) Finally, the two last architectures (dual polarizations), can’t be distinguished only by the number of
bands of the input image.
User must then use the parameters emissionh and emissionv to indicate the architecture of the system :
emissionh=1 and emissionv=0 –>HH_HV, emissionh=0 and emissionv=1 –>VH_VV.
Note : if the architecture is HH_HV, khii and psii are automatically set to 0°/0°; if the architecture is
VH_VV, khii and psii are automatically set to 0°/90°.
It is also possible to force the calculation to co-polar or cross-polar modes.
In the co-polar case, values for psir and khir will be ignored and forced to psii and khii; same as the
cross-polar mode, where khir and psir will be forced to psii+90° and -khii.
Finally, the result of the polarimetric synthetis is expressed in the power domain, through a one-band scalar
image.
Note: this application doesn’t take into account the terms which do not depend on the polarization of the
antennas.
The parameter gain can be used for this purpose.
More details can be found in the OTB CookBook (SAR processing chapter).
This section describes in details the parameters available for this application. Table 4.176, page 851 presents a summary of these parameters and the parameters keys to be used in command-line and programming languages. Application key is SARPolarSynth.
Parameter key | Parameter type |
Parameter description |
in | Input image |
Input Image |
out | Output image |
Output Image |
psii | Float |
psii |
khii | Float |
khii |
psir | Float |
psir |
khir | Float |
khir |
emissionh | Int |
Emission H |
emissionv | Int |
Emission V |
mode | Choices |
Forced mode |
mode none | Choice |
None |
mode co | Choice |
Copolarization |
mode cross | Choice |
Crosspolarization |
ram | Int |
Available RAM (Mb) |
inxml | XML input parameters file |
Load otb application from xml file |
outxml | XML output parameters file |
Save otb application to xml file |
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To run this example in command-line, use the following:
To run this example from Python, use the following code snippet:
None
This application has been written by OTB-Team.
These additional ressources can be useful for further information: