ITK  5.2.0
Insight Toolkit
Examples/Filtering/MathematicalMorphologyBinaryFilters.cxx
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*
* Copyright NumFOCUS
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* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
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// Software Guide : BeginCommandLineArgs
// INPUTS: {BrainProtonDensitySlice.png}
// OUTPUTS: {MathematicalMorphologyBinaryErosionOutput.png}
// OUTPUTS: {MathematicalMorphologyBinaryDilationOutput.png}
// ARGUMENTS: 150 180
// Software Guide : EndCommandLineArgs
// Software Guide : BeginLatex
//
// The following section illustrates the use of filters that perform basic
// mathematical morphology operations on binary images. The
// \doxygen{BinaryErodeImageFilter} and \doxygen{BinaryDilateImageFilter} are
// described here. The filter names clearly specify the type of image on
// which they operate. The header files required to construct a simple
// example of the use of the mathematical morphology filters are included
// below.
//
// \index{itk::BinaryDilateImageFilter!header}
// \index{itk::BinaryErodeImageFilter!header}
//
// Software Guide : EndLatex
#include "itkImage.h"
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
int
main(int argc, char * argv[])
{
if (argc < 6)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImageFile ";
std::cerr << " outputImageFileErosion outputImageFileDilation";
std::cerr << " lowerThreshold upperThreshold " << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// The following code defines the input and output pixel types and their
// associated image types.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
constexpr unsigned int Dimension = 2;
using InputPixelType = unsigned char;
using OutputPixelType = unsigned char;
using InputImageType = itk::Image<InputPixelType, Dimension>;
using OutputImageType = itk::Image<OutputPixelType, Dimension>;
// Software Guide : EndCodeSnippet
using ThresholdFilterType =
// Software Guide : BeginLatex
//
// Mathematical morphology operations are implemented by applying an
// operator over the neighborhood of each input pixel. The combination of
// the rule and the neighborhood is known as \emph{structuring
// element}. Although some rules have become de facto standards for image
// processing, there is a good deal of freedom as to what kind of
// algorithmic rule should be applied to the neighborhood. The
// implementation in ITK follows the typical rule of minimum for
// erosion and maximum for dilation.
//
// The structuring element is implemented as a NeighborhoodOperator. In
// particular, the default structuring element is the
// \doxygen{BinaryBallStructuringElement} class. This class is instantiated
// using the pixel type and dimension of the input image.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using StructuringElementType =
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The structuring element type is then used along with the input and
// output image types for instantiating the type of the filters.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using ErodeFilterType = itk::BinaryErodeImageFilter<InputImageType,
OutputImageType,
StructuringElementType>;
using DilateFilterType =
OutputImageType,
StructuringElementType>;
// Software Guide : EndCodeSnippet
// Creation of Reader and Writer filters
ReaderType::Pointer reader = ReaderType::New();
WriterType::Pointer writerDilation = WriterType::New();
WriterType::Pointer writerErosion = WriterType::New();
ThresholdFilterType::Pointer thresholder = ThresholdFilterType::New();
// Software Guide : BeginLatex
//
// The filters can now be created by invoking the \code{New()} method and
// assigning the result to \doxygen{SmartPointer}s.
//
// \index{itk::BinaryDilateImageFilter!New()}
// \index{itk::BinaryErodeImageFilter!New()}
// \index{itk::BinaryDilateImageFilter!Pointer}
// \index{itk::BinaryErodeImageFilter!Pointer}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
ErodeFilterType::Pointer binaryErode = ErodeFilterType::New();
DilateFilterType::Pointer binaryDilate = DilateFilterType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The structuring element is not a reference counted class. Thus it is
// created as a C++ stack object instead of using \code{New()} and
// SmartPointers. The radius of the neighborhood associated with the
// structuring element is defined with the \code{SetRadius()} method and
// the \code{CreateStructuringElement()} method is invoked in order to
// initialize the operator. The resulting structuring element is passed to
// the mathematical morphology filter through the \code{SetKernel()}
// method, as illustrated below.
//
// \index{itk::BinaryBallStructuringElement!SetRadius()}
// \index{itk::BinaryBallStructuringElement!CreateStructuringElement()}
// \index{itk::BinaryDilateImageFilter!SetKernel()}
// \index{itk::BinaryErodeImageFilter!SetKernel()}
// \index{SetRadius()!itk::BinaryBallStructuringElement}
// \index{SetKernel()!itk::BinaryDilateImageFilter}
// \index{SetKernel()!itk::BinaryErodeImageFilter}
// \index{SetRadius()!itk::BinaryBallStructuringElement}
// \index{CreateStructuringElement()!itk::BinaryBallStructuringElement}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
StructuringElementType structuringElement;
structuringElement.SetRadius(1); // 3x3 structuring element
structuringElement.CreateStructuringElement();
binaryErode->SetKernel(structuringElement);
binaryDilate->SetKernel(structuringElement);
// Software Guide : EndCodeSnippet
reader->SetFileName(argv[1]);
writerErosion->SetFileName(argv[2]);
writerDilation->SetFileName(argv[3]);
// Software Guide : BeginLatex
//
// A binary image is provided as input to the filters. This image might be,
// for example, the output of a binary threshold image filter.
//
// Software Guide : EndLatex
const InputPixelType lowerThreshold = std::stoi(argv[4]);
const InputPixelType upperThreshold = std::stoi(argv[5]);
// Software Guide : BeginCodeSnippet
thresholder->SetInput(reader->GetOutput());
InputPixelType background = 0;
InputPixelType foreground = 255;
thresholder->SetOutsideValue(background);
thresholder->SetInsideValue(foreground);
thresholder->SetLowerThreshold(lowerThreshold);
thresholder->SetUpperThreshold(upperThreshold);
// Software Guide : EndCodeSnippet
// Software Guide : BeginCodeSnippet
binaryErode->SetInput(thresholder->GetOutput());
binaryDilate->SetInput(thresholder->GetOutput());
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The values that correspond to ``objects'' in the binary image are
// specified with the methods \code{SetErodeValue()} and
// \code{SetDilateValue()}. The value passed to these methods will be
// considered the value over which the dilation and erosion rules will
// apply.
//
// \index{itk::BinaryDilateImageFilter!SetDilateValue()}
// \index{itk::BinaryErodeImageFilter!SetErodeValue()}
// \index{SetDilateValue()!itk::BinaryDilateImageFilter}
// \index{SetErodeValue()!itk::BinaryErodeImageFilter}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
binaryErode->SetErodeValue(foreground);
binaryDilate->SetDilateValue(foreground);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The filter is executed by invoking its \code{Update()} method, or by
// updating any downstream filter, such as an image writer.
//
// \index{itk::BinaryDilateImageFilter!Update()}
// \index{itk::BinaryErodeImageFilter!Update()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
writerDilation->SetInput(binaryDilate->GetOutput());
writerDilation->Update();
// Software Guide : EndCodeSnippet
writerErosion->SetInput(binaryErode->GetOutput());
writerErosion->Update();
// Software Guide : BeginLatex
//
// \begin{figure}
// \center
// \includegraphics[width=0.32\textwidth]{BinaryThresholdImageFilterOutput}
// \includegraphics[width=0.32\textwidth]{MathematicalMorphologyBinaryErosionOutput}
// \includegraphics[width=0.32\textwidth]{MathematicalMorphologyBinaryDilationOutput}
// \itkcaption[Effect of erosion and dilation in a binary image.]{Effect of
// erosion and dilation in a binary image.}
// \label{fig:MathematicalMorphologyBinaryFilters}
// \end{figure}
//
// Figure \ref{fig:MathematicalMorphologyBinaryFilters} illustrates the
// effect of the erosion and dilation filters on a binary image from a MRI
// brain slice. The figure shows how these operations can be used to remove
// spurious details from segmented images.
//
// Software Guide : EndLatex
return EXIT_SUCCESS;
}
itk::BinaryBallStructuringElement
A Neighborhood that represents a ball structuring element (ellipsoid) with binary elements.
Definition: itkBinaryBallStructuringElement.h:62
itkBinaryDilateImageFilter.h
itk::BinaryThresholdImageFilter
Binarize an input image by thresholding.
Definition: itkBinaryThresholdImageFilter.h:139
itkImageFileReader.h
itkImage.h
itk::BinaryErodeImageFilter
Fast binary erosion of a single intensity value in the image.
Definition: itkBinaryErodeImageFilter.h:72
itkBinaryBallStructuringElement.h
itk::ImageFileReader
Data source that reads image data from a single file.
Definition: itkImageFileReader.h:75
itk::BinaryDilateImageFilter
Fast binary dilation of a single intensity value in the image.
Definition: itkBinaryDilateImageFilter.h:70
itk::ImageFileWriter
Writes image data to a single file.
Definition: itkImageFileWriter.h:87
itkBinaryErodeImageFilter.h
itk::KernelImageFilter::SetRadius
void SetRadius(const RadiusType &radius) override
itkImageFileWriter.h
itkBinaryThresholdImageFilter.h
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:86
itk::GTest::TypedefsAndConstructors::Dimension2::Dimension
constexpr unsigned int Dimension
Definition: itkGTestTypedefsAndConstructors.h:44