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ImageDev

IntensityHistogram

Computes the histogram of a gray level image.

Access to parameter description

For an introduction: For each gray level i of the input image, the number of pixels with intensity i is computed.
This number of points per level is given in an histogram array. The histogram size depends on the intensity range. As an example, for an 8-bit integer image, the histogram H is an array with 256 entries. H(i) is the number of pixels at level i, for i∈[0,255].

Notice: This algorithm can be used only on integer input images. The IntensityBinHistogram algorithm must be used to compute a histogram on floating point images.

See also

Function Syntax

This function returns the outputMeasurement output parameter. 
// Function prototype.
IntensityHistogramMsr::Ptr
intensityHistogram( std::shared_ptr< iolink::ImageView > inputImage,
                    IntensityHistogram::RangeMode rangeMode,
                    iolink::Vector2i32 intensityInputRange,
                    IntensityHistogramMsr::Ptr outputMeasurement = NULL );

Class Syntax

Parameters

Class Name IntensityHistogram

Parameter Name Description Type Supported Values Default Value
input
inputImage
The input gray scale image. Float images are not supported Image Binary, Label, Grayscale or Multispectral nullptr
input
rangeMode
The way to determine the input intensity range within which the histogram is computed.
MIN_MAX This histogram is computed between the minimum and the maximum of the image.
OTHER This histogram is computed between user-defined bounds [a,b].
Enumeration MIN_MAX
input
intensityInputRange
The input intensity range [a,b] within which the histogram is computed. This parameter is ignored if the range mode is set to MIN_MAX. Vector2i32 Any value {0, 255}
output
outputMeasurement
The output histogram. IntensityHistogramMsr nullptr

Object Examples

std::shared_ptr< iolink::ImageView > polystyrene = ioformat::readImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene.tif" );

IntensityHistogram intensityHistogramAlgo;
intensityHistogramAlgo.setInputImage( polystyrene );
intensityHistogramAlgo.setRangeMode( IntensityHistogram::RangeMode::MIN_MAX );
intensityHistogramAlgo.setIntensityInputRange( {0, 255} );
intensityHistogramAlgo.execute();

std::cout << "intensityValue: " << intensityHistogramAlgo.outputMeasurement()->intensityValue( 0 ) ;

Function Examples

std::shared_ptr< iolink::ImageView > polystyrene = ioformat::readImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene.tif" );

auto result = intensityHistogram( polystyrene, IntensityHistogram::RangeMode::MIN_MAX, {0, 255} );

std::cout << "intensityValue: " << result->intensityValue( 0 ) ;