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graycoprops

Properties of gray-level co-occurrence matrix

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Syntax

stats = graycoprops(glcm,properties)

Description

example

stats= graycoprops(glcm,properties)calculates the statistics specified inpropertiesfrom the gray-level co-occurrence matrixglcm.glcmis anm-by-n-by-parray of valid gray-level co-occurrence matrices. Ifglcmis an array of GLCMs,statsis an array of statistics for eachglcm.

graycopropsnormalizes the gray-level co-occurrence matrix (GLCM) so that the sum of its elements is equal to1. Each element (r,c)应用灰度共生矩阵建立规范化的联合概率occurrence of pixel pairs with a defined spatial relationship having gray level valuesrandcin the image.graycopropsuses the normalized GLCM to calculateproperties.

Examples

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Open Live Script

Create simple sample GLCM.

glcm = [0 1 2 3;1 1 2 3;1 0 2 0;0 0 0 3]
glcm =4×40 1 2 3 1 1 2 3 1 0 2 0 0 0 0 3

Calculate statistical properties of the GLCM.

stats = graycoprops(glcm)
stats =struct with fields:Contrast: 2.8947 Correlation: 0.0783 Energy: 0.1191 Homogeneity: 0.5658
Open Live Script

Read grayscale image into the workspace.

I = imread('circuit.tif');

Create two gray-level co-occurrence matrices (GLCM) from the image, specifying different offsets.

glcm = graycomatrix(I,'Offset',[2 0;0 2])
glcm = glcm(:,:,1) = Columns 1 through 6 14205 2107 126 0 0 0 2242 14052 3555 400 0 0 191 3579 7341 1505 37 0 0 683 1446 7184 1368 0 0 7 116 1502 10256 1124 0 0 0 2 1153 1435 0 0 0 0 0 0 0 0 0 0 0 0 Columns 7 through 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 glcm(:,:,2) = Columns 1 through 6 13938 2615 204 4 0 0 2406 14062 3311 630 23 0 145 3184 7371 1650 133 0 2 371 1621 6905 1706 0 0 0 116 1477 9974 1173 0 0 0 1 1161 1417 0 0 0 0 0 0 0 0 0 0 0 0 Columns 7 through 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Get statistics on contrast and homogeneity of the image from the GLCMs.

stats = graycoprops(glcm,{'contrast','homogeneity'})
stats =struct with fields:Contrast: [0.3420 0.3567] Homogeneity: [0.8567 0.8513]

Input Arguments

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Gray-level Co-occurrence Matrix, specified as a real, non-negative array of finite logical or numeric integers. Use the graycomatrix function to create a GLCM.

Data Types:single|double|int8|int16|int32|int64|uint8|uint16|uint32|uint64|logical

Statistical properties of the image derived from GLCM, specified as a comma-separated list string scalars or character vectors, space-separated string scalar or character vector, cell array of string scalars or character vectors, or'all'. You can specify any of the property names listed in this table. Property names can be abbreviated and are not case sensitive.

Property

Description

Formula

'Contrast'

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.

The property Contrast is also known asvarianceandinertia.

'Correlation'

Returns a measure of how correlated a pixel is to its neighbor over the whole image.

Range = [-1 1]

Correlation is 1 or -1 for a perfectly positively or negatively correlated image. Correlation isNaNfor a constant image.

'Energy'

Returns the sum of squared elements in the GLCM.

Range = [0 1]

Energy is1for a constant image.

The property Energy is also known asuniformity,uniformity of energy, andangular second moment.

'Homogeneity'

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.

Data Types:char|string|cell

Output Arguments

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Statistics derived from the GLCM, returned as a structure with fields that are specified byproperties. Each field contains a 1-by-parray, wherepis the number of gray-level co-occurrence matrices in GLCM. For example, if GLCM is an 8-by-8-by-3 array and properties is'Energy',statsis a structure containing the fieldEnergy, which contains a 1-by-3 array.

See Also

Introduced before R2006a

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