VertexComponentAnalysis - Vertex Component Analysis
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Given a set of mixed spectral vectors, estimatereference substances also known as endmembers using the VertexComponent Analysis algorithm.

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

Apply the Vertex Component Analysis [1] toan hyperspectral image to extract endmembers. Given a set of mixedspectral vectors (multispectral or hyperspectral), the applicationestimates the spectral signature of reference substances also knownas endmembers.

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 *VertexComponentAnalysis* .

.. [#] Table: Parameters table for Vertex Component Analysis.

+-------------+----------------------------------+--------------------------+
|Parameter Key|Parameter Name                    |Parameter Type            |
+=============+==================================+==========================+
|in           |Input Image                       |Input image               |
+-------------+----------------------------------+--------------------------+
|ne           |Number of endmembers              |Int                       |
+-------------+----------------------------------+--------------------------+
|outendm      |Output Endmembers                 |Output image              |
+-------------+----------------------------------+--------------------------+
|rand         |set user defined seed             |Int                       |
+-------------+----------------------------------+--------------------------+
|inxml        |Load otb application from xml file|XML input parameters file |
+-------------+----------------------------------+--------------------------+
|outxml       |Save otb application to xml file  |XML output parameters file|
+-------------+----------------------------------+--------------------------+

- **Input Image**: Input hyperspectral data cube.
- **Number of endmembers**: The number of endmembers to extract from the hyperspectral image.
- **Output Endmembers**: Endmembers, stored in aone-line multi-spectral image.Each pixel corresponds to oneendmembers and each band values corresponds to the spectralsignature of the corresponding endmember.
- **set user defined seed**: Set specific seed. with integer value.
- **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_VertexComponentAnalysis -in cupriteSubHsi.tif -ne 5 -outendm VertexComponentAnalysis.tif double

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 VertexComponentAnalysis application 
	VertexComponentAnalysis = otbApplication.Registry.CreateApplication("VertexComponentAnalysis")

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

	VertexComponentAnalysis.SetParameterInt("ne", 5)

	VertexComponentAnalysis.SetParameterString("outendm", "VertexComponentAnalysis.tif")
	VertexComponentAnalysis.SetParameterOutputImagePixelType("outendm", 7)

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

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

None

Authors
~~~~~~~

This application has been written by OTB-Team.

See Also
~~~~~~~~

These additional resources can be useful for further information: 
  | [1] J. M. P. Nascimento and J. M. B. Dias, Vertexcomponent analysis: a fast algorithm to unmix hyperspectral data,in IEEE Transactions on Geoscience and Remote Sensing, vol. 43,no. 4, pp. 898-910, April 2005.J. M. P. Nascimento andJ. M. B. Dias, Vertex component analysis: a fast algorithm tounmix hyperspectral data, in IEEE Transactions on Geoscience andRemote Sensing, vol. 43, no. 4, pp. 898-910, April 2005.