International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
Si m Rune it Son )
Sia ET IK SahShv + SiS 3
1
Sa1 = 5 San“ + (Saul: + Syn]? mt Sl
1
Sy = = (ISnnl” + ISl = Sri + Sel.)
$235 = RSS h^ TR S Sun)
S24 = Sahne T. Sin)
S31 = R(ShnSon = SueSvo!)
S32 = R(SpnSun” — SoS)
Sas m RS Sup d Susp.)
Sy = HsnnSue + 5150")
$41 = 1(SnnSno + ShoSvv )
Saz = 1(SnnSon — ShvSvv )
Sas = 1 SppSyv. + SraSon À
$44 = RS nn Sue x SpySyh )
Once these expressions are calculated, it is
output on the GUI in the form of unsymmetric
Stokes matrix (after normalization).This is
followed by calculation of Stokes unit vector
(2) for transmitted (T) and received(R) antenna.
So 1
5 S: cos 2,C0Sy
cH $; dcos 2, Sin2g
$4 sin2,
The element SO is the total power in the wave.
The element S1 represents the difference in
energy between the two orthogonal components
of the wave. The elements S2 and S3 jointly
represent the phase difference between the two
orthogonal components of the electric field.
Backscattered power (P) is then calculated by
the expression (3), for both Co-polarization and
Cross polarization.
{Poy} = s [K]S7
In order to compute the Co-polarization and
Cross polarization signatures, the above
equation is used with values of Ellipticity (X)
and Orientation( @ ) angles varying with
increments of 5° (-45° to +45° for X and 0° to
180° for @ ). The result is output on the GUI in
the form of a table and 3D plot showing
backscattered power at various ellipticity (X)
and orientation (@) angles, for both polarization
cases.
Figure 2.3a: Polarization Response of Dihedral corner
reflector obtained “Radar Polarimetry for Geoscience
Applications”
537
RATS e 35
%
FOLARESATAN Duc KEE.
Figure2.3b: Polarization Response of Dihedral corner
reflector obtained from developed tool “POLSIC”
From the above figures it is seen that the
polarization response of a dihedral corner
reflector generated by the developed tool
“POLSIC” is similar to that provided in “Radar
Polarimetry for Geoscience Applications”.The
power axis in the developed tool changes
dynamically with the zoom level.
3. RESULTS AND DISCUSSION
The urban classes considered in this study, to
carry out the analysis include: Built up (within
water body and within city), linear features like
roads and bridge, vegetated land, open field,
and water body. These targets were identified
from the multipolarization RADARSAT-2
imagery, using RAT 0.21 software. The RAT
0.21 software is freeware radar processing
software that has the facility to view the
geocoded product, and provide information of
the real coordinates for various points on the
image, along with the amplitude and phase
values of a point target in all the four
polarization channels (HH, VV, HV, and VH).
Using the ground truth data available for the
study area, the accuracy check was carried out
and it was found that the geocoding done by
RAT 0.21software was accurate and the only
difference was in the decimal value of the
second's part. These targets were then verified
