entropy_grayentropy_grayentropy_grayEntropyGrayEntropyGray (Operator)

Name

entropy_grayentropy_grayentropy_grayEntropyGrayEntropyGray — Determine the entropy and anisotropy of images.

Signature

Description

The operator entropy_grayentropy_grayentropy_grayEntropyGrayEntropyGray creates the histogram of relative frequencies of the gray values in the input image and calculates from these frequencies the entropy and the anisotropy coefficient for each region from RegionsRegionsRegionsRegionsregions according to the following formulae:

    Entropy:
                                 255
                                 ----
                                 \
                Entropy  =     - /     rel[i]  *  ld(rel[i])
                                 ----
                                  0

    Anisotropiy coefficient:
                                  k
                                 ----
                                 \
                                 /     rel[i]  *  ld(rel[i])
                                 ----
                                  0
                Anisotropy  =  -----------------------------
                                        Entropy

        where
                rel[i]  histogram of relative gray value frequencies
                i       Gray value of input image (0..255)
        and     k       Smallest possible gray value with sum(rel[i]) >= 0.5

Parallelization

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Automatically parallelized on tuple level.

Parameters

Complexity

If F is the area of the region the runtime complexity is O(F + 255).

Result

The operator entropy_grayentropy_grayentropy_grayEntropyGrayEntropyGray returns the value 2 (H_MSG_TRUE) if an image with defined gray values is entered 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>:)set_system("no_object_result",<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>), the behavior in case of empty region is set via set_system(::'empty_region_result',<Result>:)set_system("empty_region_result",<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>). If necessary an exception is raised.

Alternatives

select_grayselect_grayselect_graySelectGraySelectGray

See also

entropy_imageentropy_imageentropy_imageEntropyImageEntropyImage, gray_histogray_histogray_histoGrayHistoGrayHisto, gray_histo_absgray_histo_absgray_histo_absGrayHistoAbsGrayHistoAbs, fuzzy_entropyfuzzy_entropyfuzzy_entropyFuzzyEntropyFuzzyEntropy, fuzzy_perimeterfuzzy_perimeterfuzzy_perimeterFuzzyPerimeterFuzzyPerimeter

Module

Foundation