.. _GridBasedImageResampling: 

GridBasedImageResampling
========================





Resamples an image according to a resampling grid

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

This application allows performing image resampling from an input resampling grid.



Parameters
----------

.. contents:: :local:

.. |br| raw:: html

   <br />

.. |em| raw:: html

   &emsp;

Input and output data
^^^^^^^^^^^^^^^^^^^^^



This group of parameters allows setting the input and output images.

**Input image** :code:`-io.in image` *Mandatory* |br|
The input image to resample

**Output Image** :code:`-io.out image [dtype]` *Mandatory* |br|
The resampled output image

Resampling grid parameters
^^^^^^^^^^^^^^^^^^^^^^^^^^





**Input resampling grid** :code:`-grid.in image` *Mandatory* |br|
The resampling grid

**Grid Type** :code:`-grid.type [def|loc]` *Default value: def* |br|
allows one to choose between two grid types

* **Displacement  grid: $G(x_out,y_out) = (x_in-x_out, y_in-y_out)$** |br| A deformation grid contains at each grid position the offset to apply to this position in order to get to the corresponding point in the input image to resample

* **Localisation grid: $G(x_out,y_out) = (x_in, y_in)$** |br| A localisation grid contains at each grid position the corresponding position in the input image to resample



Output Image parameters
^^^^^^^^^^^^^^^^^^^^^^^



Parameters of the output image

**Upper Left X** :code:`-out.ulx float` *Default value: 0* |br|
X Coordinate of the upper-left pixel of the output resampled image

**Upper Left Y** :code:`-out.uly float` *Default value: 0* |br|
Y Coordinate of the upper-left pixel of the output resampled image

**Size X** :code:`-out.sizex int` *Mandatory* |br|
Size of the output resampled image along X (in pixels)

**Size Y** :code:`-out.sizey int` *Mandatory* |br|
Size of the output resampled image along Y (in pixels)

**Pixel Size X** :code:`-out.spacingx float` *Default value: 1* |br|
Size of each pixel along X axis

**Pixel Size Y** :code:`-out.spacingy float` *Default value: 1* |br|
Size of each pixel along Y axis

**Default value** :code:`-out.default float` *Default value: 0* |br|
The default value to give to pixel that falls outside of the input image.



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

**Interpolation** :code:`-interpolator [nn|linear|bco]` *Default value: bco* |br|
This group of parameters allows one to define how the input image will be interpolated during resampling.

* **Nearest Neighbor interpolation** |br| Nearest neighbor interpolation leads to poor image quality, but it is very fast.

* **Linear interpolation** |br| Linear interpolation leads to average image quality but is quite fast

* **Bicubic interpolation** |br| 



Bicubic interpolation options
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

**Radius for bicubic interpolation** :code:`-interpolator.bco.radius int` *Default value: 2* |br|
This parameter allows controlling the size of the bicubic interpolation filter. If the target pixel size is higher than the input pixel size, increasing this parameter will reduce aliasing artifacts.



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

**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_GridBasedImageResampling -io.in ROI_IKO_PAN_LesHalles_sub.tif -io.out ROI_IKO_PAN_LesHalles_sub_resampled.tif uint8 -grid.in ROI_IKO_PAN_LesHalles_sub_deformation_field.tif -out.sizex 256 -out.sizey 256 -grid.type def


From Python:

.. code-block:: python

	import otbApplication

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

	app.SetParameterString("io.in", "ROI_IKO_PAN_LesHalles_sub.tif")
	app.SetParameterString("io.out", "ROI_IKO_PAN_LesHalles_sub_resampled.tif")
	app.SetParameterOutputImagePixelType("io.out", 1)
	app.SetParameterString("grid.in", "ROI_IKO_PAN_LesHalles_sub_deformation_field.tif")
	app.SetParameterInt("out.sizex", 256)
	app.SetParameterInt("out.sizey", 256)
	app.SetParameterString("grid.type","def")

	app.ExecuteAndWriteOutput()





See also
--------

| otbStereorecificationGridGeneration