.. _HaralickTextureExtraction: 

HaralickTextureExtraction
=========================





Computes Haralick textural features on the selected channel of the input image

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

This application computes three sets of Haralick features [1][2].

* simple: a set of 8 local Haralick features: Energy (texture uniformity) , Entropy (measure of randomness of intensity image), Correlation (how correlated a pixel is to its neighborhood), Inverse Difference Moment (measures the texture homogeneity), Inertia (intensity contrast between a pixel and its neighborhood), Cluster Shade, Cluster Prominence, Haralick Correlation;

* advanced: a set of 10 advanced Haralick features: Mean, Variance (measures the texture heterogeneity), Dissimilarity, Sum Average, Sum Variance, Sum Entropy, Difference of Entropies, Difference of Variances, IC1, IC2;

* higher: a set of 11 higher Haralick features: Short Run Emphasis (measures the texture sharpness), Long Run Emphasis (measures the texture roughness), Grey-Level Nonuniformity, Run Length Nonuniformity, Run Percentage (measures the texture sharpness homogeneity), Low Grey-Level Run Emphasis, High Grey-Level Run Emphasis, Short Run Low Grey-Level Emphasis, Short Run High Grey-Level Emphasis, Long Run Low Grey-Level Emphasis and Long Run High Grey-Level Emphasis.

The documentation of textures (description are formulas) are available in the OTB CookBook (section Textures) and also in corresponding doxygen documentation of filters (see section *Detailed Description* in doxygen):
* **simple**: otbScalarImageToTexturesFilter
* **advanced**: otbScalarImageToAdvancedTexturesFilter
* **higher**: otbScalarImageToHigherOrderTexturesFilter



Parameters
----------

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**Input Image** :code:`-in image` *Mandatory* |br|
The input image to compute the features on.

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

**Computation step** :code:`-step int` *Default value: 1* |br|
Step (in pixels) to compute output texture values. The first computed pixel position is shifted by (step-1)/2 in both directions.

Texture feature parameters
^^^^^^^^^^^^^^^^^^^^^^^^^^



This group of parameters allows one to define texture parameters.

**X Radius** :code:`-parameters.xrad int` *Default value: 2* |br|
X Radius of the neighborhood window. The formula used to retrieve the size of the window is ``2 * radius + 1``.

**Y Radius** :code:`-parameters.yrad int` *Default value: 2* |br|
Y Radius of the neighborhood window. The formula used to retrieve the size of the window is ``2 * radius + 1``.

**X Offset** :code:`-parameters.xoff int` *Default value: 1* |br|
X Offset

**Y Offset** :code:`-parameters.yoff int` *Default value: 1* |br|
Y Offset

**Image Minimum** :code:`-parameters.min float` *Default value: 0* |br|
Image Minimum

**Image Maximum** :code:`-parameters.max float` *Default value: 255* |br|
Image Maximum

**Histogram number of bin** :code:`-parameters.nbbin int` *Default value: 8* |br|
Histogram number of bin



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

**Texture Set Selection** :code:`-texture [simple|advanced|higher]` *Default value: simple* |br|
Choice of The Texture Set

* **Simple Haralick Texture Features** |br| This group of parameters defines the 8 local Haralick texture feature output image. The image channels are: Energy, Entropy, Correlation, Inverse Difference Moment, Inertia, Cluster Shade, Cluster Prominence and Haralick Correlation

* **Advanced Texture Features** |br| This group of parameters defines the 10 advanced texture feature output image. The image channels are: Mean, Variance, Dissimilarity, Sum Average, Sum Variance, Sum Entropy, Difference of Entropies, Difference of Variances, IC1 and IC2

* **Higher Order Texture Features** |br| This group of parameters defines the 11 higher order texture feature output image. The image channels are: Short Run Emphasis, Long Run Emphasis, Grey-Level Nonuniformity, Run Length Nonuniformity, Run Percentage, Low Grey-Level Run Emphasis, High Grey-Level Run Emphasis, Short Run Low Grey-Level Emphasis, Short Run High Grey-Level Emphasis, Long Run Low Grey-Level Emphasis and Long Run High Grey-Level Emphasis



**Output Image** :code:`-out image [dtype]` |br|
Output image containing the selected texture features.

**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_HaralickTextureExtraction -in qb_RoadExtract.tif -channel 2 -parameters.xrad 3 -parameters.yrad 3 -texture simple -out HaralickTextures.tif


From Python:

.. code-block:: python

	import otbApplication

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

	app.SetParameterString("in", "qb_RoadExtract.tif")
	app.SetParameterInt("channel", 2)
	app.SetParameterInt("parameters.xrad", 3)
	app.SetParameterInt("parameters.yrad", 3)
	app.SetParameterString("texture","simple")
	app.SetParameterString("out", "HaralickTextures.tif")

	app.ExecuteAndWriteOutput()



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

The computation of the features is based on a Gray Level Co-occurrence matrix (GLCM) from the quantized input image. Consequently the quantization parameters (min, max, nbbin) must be appropriate to the range of the pixel values.

See also
--------

| [1] HARALICK, Robert M., SHANMUGAM, Karthikeyan, et al. Textural features for image classification. IEEE Transactions on systems, man, and cybernetics, 1973, no 6, p. 610-621.
| [2] otbScalarImageToTexturesFilter, otbScalarImageToAdvancedTexturesFilter and otbScalarImageToHigherOrderTexturesFilter classes