Properties of gray-level co-occurrence matrix

`stats = graycoprops(glcm, properties)`

`stats = graycoprops(glcm, properties)`

calculates
the statistics specified in `properties`

from the
gray-level co-occurence matrix `glcm`

. `glcm`

is
an *m*-by-*n*-by-*p* array
of valid gray-level co-occurrence matrices. If `glcm`

is
an array of GLCMs, `stats`

is an array of statistics
for each `glcm`

.

`graycoprops`

normalizes the gray-level co-occurrence
matrix (GLCM) so that the sum of its elements is equal to `1`

.
Each element (r,c) in the normalized GLCM is the joint probability
occurrence of pixel pairs with a defined spatial relationship having
gray level values r and c in the image. `graycoprops`

uses
the normalized GLCM to calculate `properties`

.

`properties`

can be a comma-separated list
of strings, a cell array containing strings, the string `'all'`

,
or a space separated string. The property names can be abbreviated
and are not case sensitive.

Property | Description | Formula |
---|---|---|

| Returns a measure of the intensity contrast between a pixel and its neighbor over the whole image. Range = [0 (size(GLCM,1)-1)^2] Contrast is 0 for a constant image. | $${{\displaystyle \sum _{i,j}\left|i-j\right|}}^{2}p(i,j)$$ |

| Returns a measure of how correlated a pixel is to its neighbor over the whole image.
Correlation
is 1 or -1 for a perfectly positively or negatively correlated image.
Correlation is | $$\sum _{i,j}\frac{(i-\mu i)(j-\mu j)p(i,j)}{{\sigma}_{i}{\sigma}_{j}}$$ |

| Returns the sum of squared elements in the GLCM. Range = [0 1] Energy
is | $$\sum _{i,j}p{(i,j)}^{2}$$ |

| Returns a value that measures the closeness of the distribution of elements in the GLCM to the GLCM diagonal. Range = [0 1] Homogeneity is 1 for a diagonal GLCM. | $$\sum _{i,j}\frac{p(i,j)}{1+\left|i-j\right|}$$ |

`stats`

is a structure with fields that are
specified by `properties`

. Each field contains a
1 x p array, where p is the number of gray-level co-occurrence matrices
in GLCM. For example, if GLCM is an 8 x 8 x 3 array and properties
is `'Energy'`

, then `stats`

is a
structure containing the field Energy, which contains a 1 x 3 array.

Energy is also known as uniformity, uniformity of energy, and angular second moment.

Contrast is also known as variance and inertia.

`glcm`

can be logical or numeric, and it must
contain real, non-negative, finite, integers. `stats`

is
a structure.

GLCM = [0 1 2 3;1 1 2 3;1 0 2 0;0 0 0 3]; stats = graycoprops(GLCM) I = imread('circuit.tif'); GLCM2 = graycomatrix(I,'Offset',[2 0;0 2]); stats = graycoprops(GLCM2,{'contrast','homogeneity'})

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