Mryka Hall-Beyer

What is texture?   The GLCM  Texture Calculations  Practical Notes   More Information and References

 Exercises     Equations

Examples of various texture calculations, on an image.

Description of the image
The image used is excerpted from Path 41, Row 25 of Landsat 7 ETM+, acquired on 4 September 1999. This is an area in the Rocky Mountain Foothills near Waterton National Park, Alberta, Canada. The western edge of the image contains steep slopes and deep valleys. To the east are both grassland and annual crops, mostly grains. The eastern area is dissected by numerous small streams or "coulees."  This image provides a variety of textures and edges.

All textures have been calculated using the red band.

Two areas have been circled in all images to make comparisons easy.

Buttons above provide links to details about each calculation and the equations used.
 

1. Basic images

Click on the desired image's thumbnail for a large picture.

Original image Standard false-colour image (rgb=TM4,3,2)	Entire image, red band only	Full resolution, red band, with subregions indicated
Detailed view of subregion 1	Detailed view of subregion 2

 

2. Various GLCM texture measures implemented

The textures below were run using a 7x7 window on the red band. All used the invariant direction, which is an average of all four spatial arrangements. Pixel offset is 1 in all cases.

Click on the desired image's thumbnail for a large picture.

Contrast	Dissimilarity using GLCM	GLDV Mean, which is the same as GLCM Dissimilarity
Homogeneity	ASM	GLCM Entropy
GLDV Entropy	GLCM Mean	GLCM Standard Deviation
GLCM Correlation

 

3. Effect of spatial relationships

The following are  entropy calculations using a 7x7 window on the identical image area.

Click on the desired image's thumbnail for a large picture.

Spatial (0,1) "North" is chosen but GLCM symmetry means that this is a "vertical" relationship, including both north (0,1) and south (0,-1) neighbours.	Spatial (1,1). "Northeast" is chosen, but GLCM symmetry means that this is a "NE (1,1)-SW (-1,-1) diagonal" relationship.

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