ClassesClasses | | Operators

min_max_graymin_max_grayMinMaxGrayMinMaxGray (Operator)

Name

min_max_graymin_max_grayMinMaxGrayMinMaxGray — Determine the minimum and maximum gray values within regions.

Signature

min_max_gray(Regions, Image : : Percent : Min, Max, Range)

Herror min_max_gray(const Hobject Regions, const Hobject Image, double Percent, double* Min, double* Max, double* Range)

Herror T_min_max_gray(const Hobject Regions, const Hobject Image, const Htuple Percent, Htuple* Min, Htuple* Max, Htuple* Range)

void MinMaxGray(const HObject& Regions, const HObject& Image, const HTuple& Percent, HTuple* Min, HTuple* Max, HTuple* Range)

void HImage::MinMaxGray(const HRegion& Regions, const HTuple& Percent, HTuple* Min, HTuple* Max, HTuple* Range) const

void HImage::MinMaxGray(const HRegion& Regions, double Percent, double* Min, double* Max, double* Range) const

void HRegion::MinMaxGray(const HImage& Image, const HTuple& Percent, HTuple* Min, HTuple* Max, HTuple* Range) const

void HRegion::MinMaxGray(const HImage& Image, double Percent, double* Min, double* Max, double* Range) const

static void HOperatorSet.MinMaxGray(HObject regions, HObject image, HTuple percent, out HTuple min, out HTuple max, out HTuple range)

void HImage.MinMaxGray(HRegion regions, HTuple percent, out HTuple min, out HTuple max, out HTuple range)

void HImage.MinMaxGray(HRegion regions, double percent, out double min, out double max, out double range)

void HRegion.MinMaxGray(HImage image, HTuple percent, out HTuple min, out HTuple max, out HTuple range)

void HRegion.MinMaxGray(HImage image, double percent, out double min, out double max, out double range)

Description

The operator min_max_graymin_max_grayMinMaxGrayMinMaxGrayMinMaxGray creates the histogram of the absolute frequencies of the gray values within RegionsRegionsRegionsRegionsregions in the input image ImageImageImageImageimage (see gray_histogray_histoGrayHistoGrayHistoGrayHisto) and calculates the number of pixels PercentPercentPercentPercentpercent corresponding to the area of the input image. Then it goes inwards on both sides of the histogram by this number of pixels and determines the smallest and the largest gray value:

  e.g.:
    Area = 60, percent = 5, i.e. 3 pixels
    Histogram = [2,8,0,7,13,0,0,...,0,10,10,5,3,1,1]
    => Maximum = 255, Minimum = 0, Range = 255

    min_max_gray returns: Maximum = 253, Minimum = 1, Range = 252
For images of type int4, int8, and real, the above calculation is not performed via histograms, but using a rank selection algorithm. If PercentPercentPercentPercentpercent is set to 50, MinMinMinMinmin = MaxMaxMaxMaxmax = Median. If PercentPercentPercentPercentpercent is 0 no histogram is calculated in order to enhance the runtime.

Attention

Note that the operator min_max_graymin_max_grayMinMaxGrayMinMaxGrayMinMaxGray only considers the given RegionsRegionsRegionsRegionsregions and ignores any previously set domain of the input image ImageImageImageImageimage.

Execution Information

Parameters

RegionsRegionsRegionsRegionsregions (input_object)  region(-array) objectHRegionHRegionHobject

Regions, the features of which are to be calculated.

ImageImageImageImageimage (input_object)  singlechannelimage objectHImageHImageHobject (byte / direction / cyclic / int1 / int2 / uint2 / int4 / int8 / real)

Gray value image.

PercentPercentPercentPercentpercent (input_control)  number HTupleHTupleHtuple (real / integer) (double / int / long) (double / Hlong) (double / Hlong)

Percentage below (above) the absolute maximum (minimum).

Default value: 0

Suggested values: 0, 1, 2, 5, 7, 10, 15, 20, 30, 40, 50

Restriction: 0 <= Percent && Percent <= 50

MinMinMinMinmin (output_control)  real(-array) HTupleHTupleHtuple (real) (double) (double) (double)

“Minimum” gray value.

MaxMaxMaxMaxmax (output_control)  real(-array) HTupleHTupleHtuple (real) (double) (double) (double)

“Maximum” gray value.

Assertion: Max >= Min

RangeRangeRangeRangerange (output_control)  real(-array) HTupleHTupleHtuple (real) (double) (double) (double)

Difference between Max and Min.

Assertion: Range >= 0

Example (HDevelop)

* Threshold segmentation with training region:
read_image(Image,'fabrik')
draw_region(Region,WindowHandle)
min_max_gray(Region,Image,5,Min,Max,Range)
threshold(Image,SegmentedRegion,Min,Max)
dev_display(SegmentedRegion)

Example (C)

/* Threshold segmentation with training region: */
read_image(&Image,"fabrik");
draw_region(&Region,WindowHandle);
min_max_gray(Region,Image,5.0,&Min,&Max,NULL);
threshold(Image,&SegmentedRegion,Min,Max);
disp_region(SegmentedRegion,WindowHandle);

Example (HDevelop)

* Threshold segmentation with training region:
read_image(Image,'fabrik')
draw_region(Region,WindowHandle)
min_max_gray(Region,Image,5,Min,Max,Range)
threshold(Image,SegmentedRegion,Min,Max)
dev_display(SegmentedRegion)

Example (HDevelop)

* Threshold segmentation with training region:
read_image(Image,'fabrik')
draw_region(Region,WindowHandle)
min_max_gray(Region,Image,5,Min,Max,Range)
threshold(Image,SegmentedRegion,Min,Max)
dev_display(SegmentedRegion)

Example (HDevelop)

* Threshold segmentation with training region:
read_image(Image,'fabrik')
draw_region(Region,WindowHandle)
min_max_gray(Region,Image,5,Min,Max,Range)
threshold(Image,SegmentedRegion,Min,Max)
dev_display(SegmentedRegion)

Result

The operator min_max_graymin_max_grayMinMaxGrayMinMaxGrayMinMaxGray returns the value 2 (H_MSG_TRUE) if the input image has the 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>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>). The behaviour in case of an empty region is set via the operator set_system(::'empty_region_result',<Result>:)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>). If necessary an exception is raised.

Possible Predecessors

draw_regiondraw_regionDrawRegionDrawRegionDrawRegion, gen_circlegen_circleGenCircleGenCircleGenCircle, gen_ellipsegen_ellipseGenEllipseGenEllipseGenEllipse, gen_rectangle1gen_rectangle1GenRectangle1GenRectangle1GenRectangle1, thresholdthresholdThresholdThresholdThreshold, regiongrowingregiongrowingRegiongrowingRegiongrowingRegiongrowing

Possible Successors

thresholdthresholdThresholdThresholdThreshold

Alternatives

select_grayselect_graySelectGraySelectGraySelectGray, intensityintensityIntensityIntensityIntensity

See also

gray_histogray_histoGrayHistoGrayHistoGrayHisto, scale_imagescale_imageScaleImageScaleImageScaleImage, scale_image_maxscale_image_maxScaleImageMaxScaleImageMaxScaleImageMax, learn_ndim_normlearn_ndim_normLearnNdimNormLearnNdimNormLearnNdimNorm

Module

Foundation


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