HALCON Reference Manual 10.0.2
Table of Contents / Image / Features ClassesClassesClasses | | | Operators

min_max_graymin_max_graymin_max_grayMinMaxGrayMinMaxGray (Operator)

Name

min_max_graymin_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)

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

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

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

HTuple HRegionArray::MinMaxGray(const HImage& Image, const HTuple& Percent, HTuple* Max, HTuple* Range) const

void HOperatorSetX.MinMaxGray(
[in] IHUntypedObjectX* Regions, [in] IHUntypedObjectX* Image, [in] VARIANT Percent, [out] VARIANT* Min, [out] VARIANT* Max, [out] VARIANT* Range)

VARIANT HImageX.MinMaxGray(
[in] IHRegionX* Regions, [in] VARIANT Percent, [out] VARIANT* Max, [out] VARIANT* Range)

VARIANT HRegionX.MinMaxGray(
[in] IHImageX* Image, [in] VARIANT Percent, [out] VARIANT* Max, [out] VARIANT* Range)

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_graymin_max_grayMinMaxGrayMinMaxGray creates the histogram of the absolute frequencies of the gray values within RegionsRegionsRegionsRegionsregions in the input image ImageImageImageImageimage (see gray_histogray_histogray_histoGrayHistoGrayHisto) 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.

Parallelization

Parameters

RegionsRegionsRegionsRegionsregions (input_object)  region(-array) → objectHRegionHRegionHRegionXHobject

Regions, the features of which are to be calculated.

ImageImageImageImageimage (input_object)  image → objectHImageHImageHImageXHobject (byte / direction / cyclic / int1 / int2 / uint2 / int4 / int8 / real)

Gray value image.

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

“Minimum” gray value.

MaxMaxMaxMaxmax (output_control)  real(-array) → HTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double)

“Maximum” gray value.

Assertion: Max >= Min

RangeRangeRangeRangerange (output_control)  real(-array) → HTupleHTupleVARIANTHtuple (real) (double) (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,_)
threshold(Image,Seg,Min,Max)
disp_region(Seg,WindowHandle)

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,&Seg,Min,Max);
disp_region(Seg,WindowHandle);

Example (C++)

#include "HalconCpp.h"
using namespace Halcon;
#include "HIOStream.h"
#if !defined(USE_IOSTREAM_H)
using namespace std;
#endif

main()
{
  HImage   img ("fabrik");
  HWindow  w;

  Htuple   range, max;

  img.Display (w);
  w.Click ();

  HRegion   reg = w.DrawRegion ();
  HImage    rdd = img.ReduceDomain (reg);

  Htuple min = reg.MinMaxGray (rdd, 5, &max, &range);

  HRegionArray imgseg = ((img >= min[0].I()).Connection() &
                         (img <= max[0].I()).Connection());

  cout << "Min = " << min[0].I() << endl;
  cout << "Max = " << max[0].I() << endl;

  imgseg.Display (w);
  w.Click ();
  return(0);
}

Example (HDevelop)

* Threshold segmentation with training region:
read_image(Image,'fabrik')
draw_region(Region,WindowHandle)
min_max_gray(Region,Image,5,Min,Max,_)
threshold(Image,Seg,Min,Max)
disp_region(Seg,WindowHandle)

Example (HDevelop)

* Threshold segmentation with training region:
read_image(Image,'fabrik')
draw_region(Region,WindowHandle)
min_max_gray(Region,Image,5,Min,Max,_)
threshold(Image,Seg,Min,Max)
disp_region(Seg,WindowHandle)

Result

The operator min_max_graymin_max_graymin_max_grayMinMaxGrayMinMaxGray 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>)set_system("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>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>). If necessary an exception is raised.

Possible Predecessors

draw_regiondraw_regiondraw_regionDrawRegionDrawRegion, gen_circlegen_circlegen_circleGenCircleGenCircle, gen_ellipsegen_ellipsegen_ellipseGenEllipseGenEllipse, gen_rectangle1gen_rectangle1gen_rectangle1GenRectangle1GenRectangle1, thresholdthresholdthresholdThresholdThreshold, regiongrowingregiongrowingregiongrowingRegiongrowingRegiongrowing

Possible Successors

thresholdthresholdthresholdThresholdThreshold

Alternatives

select_grayselect_grayselect_graySelectGraySelectGray, intensityintensityintensityIntensityIntensity

See also

gray_histogray_histogray_histoGrayHistoGrayHisto, scale_imagescale_imagescale_imageScaleImageScaleImage, scale_image_maxscale_image_maxscale_image_maxScaleImageMaxScaleImageMax, learn_ndim_normlearn_ndim_normlearn_ndim_normLearnNdimNormLearnNdimNorm

Module

Foundation

Table of Contents / Image / Features ClassesClassesClasses | | | Operators
HALCON Reference Manual 10.0.2 Copyright © 1996-2011 MVTec Software GmbH