cooc_feature2 ( CoocMatrix : : : Energy, Correlation, Homogenity, Contrast )

Calculate gray value features from a co-occurrence matrix.

The procedure calculates from a co-occurence matrix (CoocMatrix) the energy (Energy), correlation (Correlation), local homogenity (Homogenity) and contrast (Contrast).

The operator cooc_feature2 calculates the gray value features from the part of the input matrix generated by gen_cooc_matrix corresponding to the direction matrix indicated by the parameters LdGrey and Direction according to the following formulae:

  Energy:
                              width   width
                              ----    ----
                              \       \
              Energy  =       /       /     cij  *  cij
                              ----    ----
                              i=0     j=0

                              (Measure for image homogenity)

  Correlation:
                              width  width
                              ----   ----
                              \      \
                              /      /      (i - ux) * (j - uy) * cij
                              ----   ----
                              i=0    j=0
              Correlation  =  -----------------------------------------
                                             sx  *  sy

                              (Measure for gray value dependencies)

  Local homogenity:

                              width  width
                              ----   ----
                              \      \
              Homogenity  =   /      /      (1 / (1+(i - j) * (i - j)) * cij
                              ----   ----
                              i=0    j=0


  Contrast:

                              width   width
                              ----    ----
                              \       \
              Contrast  =     /       /     (i - j)  *  (i - j)  *  cij
                              ----    ----
                              i=0     j=0

                      (Measure for the size of the intensity differences)

      where

              width           2^LdGrey - 1

              cij             Entry of co-occurrence matrix

                              width   width
                              ----    ----
                              \       \
              ux              /       /     i  *  cij
                              ----    ----
                              i=0     j=0

                              width   width
                              ----    ----
                              \       \
              uy              /       /     j  *  cij
                              ----    ----
                              i=0     j=0

                              width   width
                              ----    ----
                              \       \
              sx^2            /       /     (i - ux)^2  * cij
                              ----    ----
                              i=0     j=0

                              width   width
                              ----    ----
                              \       \
              sy^2            /       /     (i - uy)^2  *  cij
                              ----    ----
                              i=0     j=0


Attention

The region of the input image is disregarded.


Parameters

CoocMatrix (input_object)
image -> object : int4
Co-occurrence matrix.

Energy (output_control)
real -> real
Homogeneity of the gray values.

Correlation (output_control)
real -> real
Correlation of gray values.

Homogenity (output_control)
real -> real
Local homogeneity of gray values.

Contrast (output_control)
real -> real
Gray value contrast.


Result

The operator cooc_feature2 returns the value TRUE if an image with defined gray values is passed and the parameters are correct. The behavior in case of empty input (no input images available) is set via the operator set_system(::'no_object_result',<Result>:). If necessary an exception is raised.


Possible Predecessors

gen_cooc_matrix


Alternatives

cooc_feature1


See also

write_cooc_matrix, intensity__, min_max__, entropy2__, select_grey__



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