SAR Radiometric calibration
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Perform radiometric calibration of SAR images. Following sensors are supported: TerraSAR-X, Sentinel1 and Radarsat-2.Both Single Look Complex(SLC) and detected products are supported as input.


Detailed description
--------------------

The objective of SAR calibration is to provide imagery in which the pixel values can be directly related to the radar backscatter of the scene. This application allows computing Sigma Naught (Radiometric Calibration) for TerraSAR-X, Sentinel1 L1 and Radarsat-2 sensors. Metadata are automatically retrieved from image products.The application supports complex and non-complex images (SLC or detected products).


Parameters
----------

This section describes in details the parameters available for this application. Table [#]_ presents a summary of these parameters and the parameters keys to be used in command-line and programming languages. Application key is *SARCalibration* .

.. [#] Table: Parameters table for SAR Radiometric calibration.

+-------------+--------------------------+----------------------------------+
|Parameter Key|Parameter Type            |Parameter Description             |
+=============+==========================+==================================+
|in           |Input image               |Input image                       |
+-------------+--------------------------+----------------------------------+
|out          |Output image              |Output image                      |
+-------------+--------------------------+----------------------------------+
|ram          |Int                       |Int                               |
+-------------+--------------------------+----------------------------------+
|noise        |Boolean                   |Boolean                           |
+-------------+--------------------------+----------------------------------+
|lut          |Choices                   |Choices                           |
+-------------+--------------------------+----------------------------------+
|lut sigma    | *Choice*                 |Use sigma nought lookup           |
+-------------+--------------------------+----------------------------------+
|lut gamma    | *Choice*                 |Use gamma nought lookup           |
+-------------+--------------------------+----------------------------------+
|lut beta     | *Choice*                 |Use beta nought lookup            |
+-------------+--------------------------+----------------------------------+
|lut dn       | *Choice*                 |Use DN value lookup               |
+-------------+--------------------------+----------------------------------+
|inxml        |XML input parameters file |XML input parameters file         |
+-------------+--------------------------+----------------------------------+
|outxml       |XML output parameters file|XML output parameters file        |
+-------------+--------------------------+----------------------------------+

- **Input Image:** Input complex image.

- **Output Image:** Output calibrated image. This image contains the backscatter (sigmaNought) of the input image.

- **Available RAM (Mb):** Available memory for processing (in MB).

- **Disable Noise:** Flag to disable noise. For 5.2.0 release, the noise values are only read by TerraSARX product.

- **Lookup table sigma /gamma/ beta/ DN.:** Lookup table values are not available with all SAR products. Products that provide lookup table with metadata are: Sentinel1, Radarsat2. Available choices are: 

- **Use sigma nought lookup** : Use Sigma nought lookup value from product metadata


- **Use gamma nought lookup** : Use Gamma nought lookup value from product metadata


- **Use beta nought lookup** : Use Beta nought lookup value from product metadata


- **Use DN value lookup** : Use DN value lookup value from product metadata



- **Load otb application from xml file:** Load otb application from xml file.

- **Save otb application to xml file:** Save otb application to xml file.



Example
-------

To run this example in command-line, use the following: 
::

	otbcli_SARCalibration -in RSAT_imagery_HH.tif -out SarRadiometricCalibration.tif

To run this example from Python, use the following code snippet: 

::

	#!/usr/bin/python

	# Import the otb applications package
	import otbApplication

	# The following line creates an instance of the SARCalibration application 
	SARCalibration = otbApplication.Registry.CreateApplication("SARCalibration")

	# The following lines set all the application parameters:
	SARCalibration.SetParameterString("in", "RSAT_imagery_HH.tif")

	SARCalibration.SetParameterString("out", "SarRadiometricCalibration.tif")

	# The following line execute the application
	SARCalibration.ExecuteAndWriteOutput()

Limitations
~~~~~~~~~~~

None

Authors
~~~~~~~

This application has been written by OTB-Team.