.. _Quicklook: 

Quicklook
=========





Generates a subsampled version of an image extract

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

Generates a subsampled version of an extract of an image defined by ROIStart and ROISize.
This extract is subsampled using the ratio OR the output image Size.



Parameters
----------

.. contents:: :local:

.. |br| raw:: html

   <br />

.. |em| raw:: html

   &emsp;

**Input Image** :code:`-in image` *Mandatory* |br|
The image to read

**Output Image** :code:`-out image [dtype]` *Mandatory* |br|
The subsampled image

**Channel List** :code:`-cl string1 string2...` |br|
Selected channels

**ROI Origin X** :code:`-rox int` *Default value: 0* |br|
first point of ROI in x-direction

**ROI Origin Y** :code:`-roy int` *Default value: 0* |br|
first point of ROI in y-direction

**ROI Size X** :code:`-rsx int` *Default value: 0* |br|
size of ROI in x-direction

**ROI Size Y** :code:`-rsy int` *Default value: 0* |br|
size of ROI in y-direction

**Sampling ratio** :code:`-sr int` *Default value: 2* |br|
Sampling Ratio, default is 2

**Size X** :code:`-sx int` |br|
quicklook size in x-direction (used if no sampling ratio is given)

**Size Y** :code:`-sy int` |br|
quicklook size in y-direction (used if no sampling ratio is given)



Examples
--------

From the command-line:

.. code-block:: bash

    otbcli_Quicklook -in qb_RoadExtract.tif -out quicklookImage.tif


From Python:

.. code-block:: python

	import otbApplication

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

	app.SetParameterString("in", "qb_RoadExtract.tif")
	app.SetParameterString("out", "quicklookImage.tif")

	app.ExecuteAndWriteOutput()



Limitations
-----------

This application does not provide yet the optimal way to decode coarser level of resolution from JPEG2000 images (like in Monteverdi).
Trying to subsampled huge JPEG200 image with the application will lead to poor performances for now.