.. _EdgeExtraction: 

EdgeExtraction
==============





This application computes edge features on every pixel of the input image selected channel

Description
-----------

This application computes edge features on a selected channel of the input.It uses different filters such as gradient, Sobel and Touzi



Parameters
----------

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**Input Image** :code:`-in image` *Mandatory* |br|
The input image on which the features are computed.

**Feature Output Image** :code:`-out image [dtype]` *Mandatory* |br|
Output image containing the edge features.

**Selected Channel** :code:`-channel int` *Default value: 1* |br|
The selected channel index

**Edge feature** :code:`-filter [gradient|sobel|touzi]` *Default value: gradient* |br|
Choice of edge feature

* **Gradient** |br| This filter computes the gradient magnitude of the image at each pixel.

* **Sobel** |br| This filter uses the Sobel operator to calculate the image gradient and then finds the magnitude of this gradient vector.

* **Touzi** |br| This filter is more suited to radar images. It has a spatial parameter to avoid speckle noise perturbations. The larger the radius is, the less sensitive the filter is to the speckle noise, but micro edge will be missed.



Touzi options
^^^^^^^^^^^^^

**X radius of the neighborhood** :code:`-filter.touzi.xradius int` *Default value: 1* |br|


**Y radius of the neighborhood** :code:`-filter.touzi.yradius int` *Default value: 1* |br|




------------

**Available RAM (MB)** :code:`-ram int` *Default value: 256* |br|
Available memory for processing (in MB).



Examples
--------

From the command-line:

.. code-block:: bash

    otbcli_EdgeExtraction -in qb_RoadExtract.tif -channel 1 -out Edges.tif


From Python:

.. code-block:: python

	import otbApplication

	app = otbApplication.Registry.CreateApplication("EdgeExtraction")

	app.SetParameterString("in", "qb_RoadExtract.tif")
	app.SetParameterInt("channel", 1)
	app.SetParameterString("out", "Edges.tif")

	app.ExecuteAndWriteOutput()





See also
--------

| otb class