gray_histo_absT_gray_histo_absgray_histo_absGrayHistoAbsGrayHistoAbs (Operator)

Name

gray_histo_absT_gray_histo_absgray_histo_absGrayHistoAbsGrayHistoAbs — Calculate the gray value distribution.

Signature

Description

The operator gray_histo_absgray_histo_absgray_histo_absGrayHistoAbsGrayHistoAbs calculates for the image (ImageImageImageImageimage) within RegionsRegionsRegionsRegionsregions the absolute (AbsoluteHistoAbsoluteHistoAbsoluteHistoAbsoluteHistoabsoluteHisto) ) histogram of the gray values.

The parameter QuantizationQuantizationQuantizationQuantizationquantization defines, how many frequencies of neighbored gray values are added for one frequency value. The resulting histogram AbsoluteHistoAbsoluteHistoAbsoluteHistoAbsoluteHistoabsoluteHisto is a tuple, whose indices are mapped on the gray values of the input image ImageImageImageImageimage and whose elements contain the frequencies of the gray values. The indices i of the frequency value are calculated from the gray values g and the quantisation q as follows:

      i = ceil((g+0.5)/q)         for unsigned image types,
      i = ceil((g-(MIN-0.5))/q)   for signed image types,

whereas MIN denotes the minimal gray value, e.g., -128 for an int1 image type. Therefore, the size of the tuple results from the ratio of the full domain of gray values and the quantisation, e.g. for images of int2 in ceil(65536/3.0) = 21846 . The origin gray value of the signed image types int1 resp. int2 is mapped on the index 128 resp. 32768, negative resp. positive gray values have smaller resp. greater indices.

The histogram can also be returned directly as a graphic via the operators set_paint(::WindowHandle,'histogram':)set_paint(WindowHandle,"histogram")set_paint(WindowHandle,"histogram")SetPaint(WindowHandle,"histogram")SetPaint(WindowHandle,"histogram") and disp_imagedisp_imagedisp_imageDispImageDispImage.

Parallelization

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

Parameters

Result

The operator gray_histo_absgray_histo_absgray_histo_absGrayHistoAbsGrayHistoAbs returns the value 2 (H_MSG_TRUE) if the image has defined gray values 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.

Possible Successors

histo_to_threshhisto_to_threshhisto_to_threshHistoToThreshHistoToThresh, gen_region_histogen_region_histogen_region_histoGenRegionHistoGenRegionHisto

Alternatives

min_max_graymin_max_graymin_max_grayMinMaxGrayMinMaxGray, intensityintensityintensityIntensityIntensity, gray_histogray_histogray_histoGrayHistoGrayHisto, gray_histo_rangegray_histo_rangegray_histo_rangeGrayHistoRangeGrayHistoRange

See also

set_paintset_paintset_paintSetPaintSetPaint, disp_imagedisp_imagedisp_imageDispImageDispImage, histo_2dimhisto_2dimhisto_2dimHisto2dimHisto2dim, scale_image_maxscale_image_maxscale_image_maxScaleImageMaxScaleImageMax, entropy_grayentropy_grayentropy_grayEntropyGrayEntropyGray

Module

Foundation