PSCONF

Description

Estimate the conformity coefficient for each pixel.

Parameters

psconf(fili, filo)

Name	Type	Caption	Length	Value range
FILI *	str	Input fully polarimetric SAR image	1 -
FILO *	str	Output conformity coefficient image	1 -

* Required parameter

Parameter descriptions

FILI

The name of the input polarimetric SAR data set, which must be either non-symmetrized or symmetrized fully polarimetric (quad-polarization) complex data. The input data set must be in scattering, covariance, coherence, or Kennaugh matrix format.

The input data must already have been imported in the PCIDSK (.pix) format by SARINGEST. Alternatively, it can be the key-file name of any GDB-supported POLSAR data set in its distribution format. For more information, and a complete list of supported POLSAR sensors and data products, see SARINGEST.

FILO

The name of the output file that will contain the conformity coefficient. The output file has the same dimensions as the input, and one channel containing the conformity coefficient, stored as floating-point pixel values.

The specified file must not already exist.

Details

The conformity coefficient can be used as an unsupervised classification technique and requires fully polarimetric data as input. When the coefficient is greater than zero, Bragg scattering is dominant, while a coefficient of less than zero indicates non-Bragg scattering is dominant. This parameter can be used to, for example, differentiate between the ambient ocean and oil slicks.

Example

Compute the conformity coefficient from a single-look RADARSAT-2 image that has already been imported in PCIDSK (.pix) format by SARINGEST.

from pci.psconf import psconf

fili	=	"rsat2_slc.pix"
filo	=	"rsat2_pow.pix"

psconf( fili, filo )

Algorithm

PSCONF computes the conformity coefficient for each pixel. If required, the input data is converted to a symmetrized covariance matrix. The real valued output is computed as:

Conformity = [2*Re(C13)-C22] / [C11+2*C22+C33]

References

Zhang B., Perrie W., Xiaofeng L., Pichel W., "Mapping sea surface oils slicks using RADARSAT-2 quad-polarization SAR Image", Geophysical Research letters, Vol. 38, May 2011.