Haralick Texture

From AWF-Wiki
(Difference between revisions)
Jump to: navigation, search
 
(16 intermediate revisions by 4 users not shown)
Line 1: Line 1:
−
{{Content Tree|HEADER=QGIS Tutorial|NAME=QGIS tutorial}}
 
−
 
 
Image texture is a quantification of the spatial variation of grey tone values. Haralick
 
Image texture is a quantification of the spatial variation of grey tone values. Haralick
−
et al. (1973) presented texture measures that may be derived by comparing the values
+
et al. (1973) suggested the use  of grey level co-occurrence matrices (GLCM). This method is based on the joint probability distributions of pairs of pixels. GLCM show how often  each  gray  level  occurs  at  a pixel  located  at  a fixed  geometric  position  relative  to  each  other  pixel, as  a function of the gray level (Srinivasan and Shobha 2008). An essential component is the definition of eight nearest-neighbor resolution cells (Fig.) that define different matrices for different angles (0°,45°,90°,135°) and distances between the horizontal neighboring pixels.
−
of the digital numbers within a window. An essential component of the concept of
+
[[File:Texture.png|center|500px|thumb|3x3 window definition and spatial  relationship for calculating Haralick texture measures. Pixel 1 and 5  are 0° (horizontal) nearest neighbors to the center pixel * ; pixel 2  and 6 are 135° nearest neighbors; pixels 3 and 7 are 90° nearest  neighbors, pixel 4 and 8 are 45° nearest neighbors to the center pixel *  (Haralick et al. 1973)]]
−
the Haralick texture measures is the definition of eight nearest-neighbor resolution cells
+
* In the search engine of the Processing Toolbox, type '''texture''' and select '''HaralickTextureExtraction''' under Feature Extraction of OTB.
−
(Fig.). Now we may define different matrices for different angles (0o,45o,90o,135o) and
+
* Under the Parameters tab, select a single band or a multiband file as input layer.
−
distances between the horizontal neighboring pixels.
+
* Select a band number in case of a multiband file under ''Selected Channel''
−
Many studies in land cover and forest type classification utilize textural features to
+
* Select the size of the neighborhood in x and y direction.
−
improve the classifcation accuracies.
+
* Specify the range of the grey levels for the specific input band in the '''Image minimum''' and '''Image maximum''' field. Check [Raster metadata] for correct values!
−
We use the ASTER satellite band number 1 (green) and an inter-pixel sampling distance
+
* Select as number of bins for the histogram: '''32'''.
−
of one. At first we need to linearly transform the 16-bit ASTER data to 8-bit radimetric
+
* Select the Texture Set: '''Simple'''
−
resolution.
+
 
 +
[[File:otb_haralick.png|400px]]
 +
 
  
−
[[File:Texture.png|center|500px|thumb|3x3 window definition and spatial  relationship for calculating Haralick texture measures. Pixel 1 and 5  are 0o (horizontal) nearest neighbors to the center pixel * ; pixel 2  and 6 are 135o nearest neighbors; pixels 3 and 7 are 90o nearest  neighbors, pixel 4 and 8 are 45o nearest neighbors to the center pixel *  (Haralick et al. 1973)]]
 
  
−
{{Exercise|message=Exercise 35|text=}}
 
  
−
==Related articles==
+
* The result file contains the following texture measures:
−
* [[Geometric feature analysis with matrix filters]]
+
# Energy
−
* [[Defining filters]]
+
# Entropy
−
* [[Low pass filter]]
+
# Correlation
−
* [[High pass filter]]
+
# Inverse Difference Moment
−
* [[Edge detection]]
+
# Inertia
 +
# Cluster Shade
 +
# Cluster Prominence
 +
# Haralick Correlation
  
−
[[category:Spatial filtering]]
+
{| class="wikitable"
 +
|style="border: 0pt" | [[file:Qgis_goe_synthesis.png|thumb|left|500px|'''Figure A:''' Input image: Sentinel-2 band B2, (University Göttingen Campus North)]]
 +
|style="border: 0pt" | [[file:Qgis_goe_synthesis_haralick.png|thumb|center|500px|'''Figure B:''' Output image: Haralick textures (RGB= Haralick Correlation, Energy, Entropy)]]
 +
|}
 +
[[category:Spatial Filtering]]

Latest revision as of 22:20, 29 November 2020

Image texture is a quantification of the spatial variation of grey tone values. Haralick et al. (1973) suggested the use of grey level co-occurrence matrices (GLCM). This method is based on the joint probability distributions of pairs of pixels. GLCM show how often each gray level occurs at a pixel located at a fixed geometric position relative to each other pixel, as a function of the gray level (Srinivasan and Shobha 2008). An essential component is the definition of eight nearest-neighbor resolution cells (Fig.) that define different matrices for different angles (0°,45°,90°,135°) and distances between the horizontal neighboring pixels.

3x3 window definition and spatial relationship for calculating Haralick texture measures. Pixel 1 and 5 are 0° (horizontal) nearest neighbors to the center pixel * ; pixel 2 and 6 are 135° nearest neighbors; pixels 3 and 7 are 90° nearest neighbors, pixel 4 and 8 are 45° nearest neighbors to the center pixel * (Haralick et al. 1973)
  • In the search engine of the Processing Toolbox, type texture and select HaralickTextureExtraction under Feature Extraction of OTB.
  • Under the Parameters tab, select a single band or a multiband file as input layer.
  • Select a band number in case of a multiband file under Selected Channel
  • Select the size of the neighborhood in x and y direction.
  • Specify the range of the grey levels for the specific input band in the Image minimum and Image maximum field. Check [Raster metadata] for correct values!
  • Select as number of bins for the histogram: 32.
  • Select the Texture Set: Simple

Otb haralick.png



  • The result file contains the following texture measures:
  1. Energy
  2. Entropy
  3. Correlation
  4. Inverse Difference Moment
  5. Inertia
  6. Cluster Shade
  7. Cluster Prominence
  8. Haralick Correlation
Figure A: Input image: Sentinel-2 band B2, (University Göttingen Campus North)
Figure B: Output image: Haralick textures (RGB= Haralick Correlation, Energy, Entropy)
Retrieved from "http://wiki.awf.forst.uni-goettingen.de/wiki/index.php?title=Haralick_Texture&oldid=16134"
Personal tools
Namespaces

Variants
Actions
Navigation
Development
Toolbox
Print/export