ITK  5.2.0
Insight Toolkit
Examples/DataRepresentation/Image/ImageAdaptor4.cxx
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// Software Guide : BeginCommandLineArgs
// INPUTS: {BrainProtonDensitySlice.png}
// OUTPUTS: {ImageAdaptorThresholdingA.png}
// ARGUMENTS: 180
// Software Guide : EndCommandLineArgs
//
// Software Guide : BeginCommandLineArgs
// INPUTS: {BrainProtonDensitySlice.png}
// OUTPUTS: {ImageAdaptorThresholdingB.png}
// ARGUMENTS: 220
// Software Guide : EndCommandLineArgs
// Software Guide : BeginLatex
//
// Image adaptors can also be used to perform simple pixel-wise computations
// on image data. The following example illustrates how to use the
// \doxygen{ImageAdaptor} for image thresholding.
//
// \index{itk::ImageAdaptor!Instantiation}
// \index{itk::ImageAdaptor!Header}
// \index{itk::ImageAdaptor!performing computation}
// \index{itk::PixelAccessor!with parameters}
// \index{itk::PixelAccessor!performing computation}
//
// Software Guide : EndLatex
// Software Guide : BeginLatex
//
// A pixel accessor for image thresholding requires that the accessor
// maintain the threshold value. Therefore, it must also implement the
// assignment operator to set this internal parameter.
//
// Software Guide : EndLatex
namespace itk
{
// Software Guide : BeginCodeSnippet
class ThresholdingPixelAccessor
{
public:
using InternalType = unsigned char;
using ExternalType = unsigned char;
ThresholdingPixelAccessor() = default;
ExternalType
Get(const InternalType & input) const
{
return (input > m_Threshold) ? 1 : 0;
}
void
SetThreshold(const InternalType threshold)
{
m_Threshold = threshold;
}
ThresholdingPixelAccessor &
operator=(const ThresholdingPixelAccessor & vpa) = default;
private:
InternalType m_Threshold{ 0 };
};
} // namespace itk
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The \code{Get()} method returns one if the input pixel is above
// the threshold and zero otherwise. The assignment operator transfers
// the value of the threshold member
// variable from one instance of the pixel accessor to another.
//
// Software Guide : EndLatex
//-------------------------
//
// Main code
//
//-------------------------
int
main(int argc, char * argv[])
{
if (argc < 4)
{
std::cerr << "Usage: " << std::endl;
std::cerr << "ImageAdaptor4 inputFileName outputBinaryFileName ";
std::cerr << " thresholdValue" << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// To create an image adaptor, we first instantiate an image type
// whose pixel type is the same as the internal pixel type of the pixel
// accessor.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using PixelType = itk::ThresholdingPixelAccessor::InternalType;
constexpr unsigned int Dimension = 2;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// We instantiate the ImageAdaptor using the image type as the
// first template parameter and the pixel accessor as the second template
// parameter.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using ImageAdaptorType =
ImageAdaptorType::Pointer adaptor = ImageAdaptorType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The threshold value is set from the command line. A threshold
// pixel accessor is created and connected to the image adaptor
// in the same manner as in the previous example.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
itk::ThresholdingPixelAccessor accessor;
accessor.SetThreshold(std::stoi(argv[3]));
adaptor->SetPixelAccessor(accessor);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// We create a reader to load the input image and connect the output
// of the reader as the input to the adaptor.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using ReaderType = itk::ImageFileReader<ImageType>;
ReaderType::Pointer reader = ReaderType::New();
reader->SetFileName(argv[1]);
reader->Update();
adaptor->SetImage(reader->GetOutput());
// Software Guide : EndCodeSnippet
using RescalerType =
RescalerType::Pointer rescaler = RescalerType::New();
using WriterType = itk::ImageFileWriter<ImageType>;
WriterType::Pointer writer = WriterType::New();
writer->SetFileName(argv[2]);
rescaler->SetOutputMinimum(0);
rescaler->SetOutputMaximum(255);
rescaler->SetInput(adaptor);
writer->SetInput(rescaler->GetOutput());
writer->Update();
// Software Guide : BeginLatex
//
// \begin{figure} \center
// \includegraphics[width=0.32\textwidth]{BrainProtonDensitySlice}
// \includegraphics[width=0.32\textwidth]{ImageAdaptorThresholdingA}
// \includegraphics[width=0.32\textwidth]{ImageAdaptorThresholdingB}
// \itkcaption[Image Adaptor for performing computations]{Using
// ImageAdaptor to perform a simple image computation. An
// ImageAdaptor is used to perform binary thresholding on
// the input image on the left. The center image was created using a
// threshold of 180, while the
// image on the right corresponds to a threshold of 220.}
// \label{fig:ImageAdaptorThresholding}
// \end{figure}
//
// As before, we rescale the emulated scalar image before writing it
// out to file.
// Figure~\ref{fig:ImageAdaptorThresholding} illustrates the result of
// applying the thresholding adaptor to a typical gray scale image using
// two different threshold values. Note that the same effect could have
// been achieved by using the \doxygen{BinaryThresholdImageFilter} but at
// the price of holding an extra copy of the image in memory.
//
// Software Guide : EndLatex
return EXIT_SUCCESS;
}
itkImageFileReader.h
itkImageAdaptor.h
itk::ImageAdaptor
Give access to partial aspects of voxels from an Image.
Definition: itkImageAdaptor.h:56
itk::ImageFileReader
Data source that reads image data from a single file.
Definition: itkImageFileReader.h:75
itk::ImageFileWriter
Writes image data to a single file.
Definition: itkImageFileWriter.h:87
itkRescaleIntensityImageFilter.h
itkImageFileWriter.h
itk
The "itk" namespace contains all Insight Segmentation and Registration Toolkit (ITK) classes....
Definition: itkAnnulusOperator.h:24
itk::RescaleIntensityImageFilter
Applies a linear transformation to the intensity levels of the input Image.
Definition: itkRescaleIntensityImageFilter.h:154
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:86
itk::GTest::TypedefsAndConstructors::Dimension2::Dimension
constexpr unsigned int Dimension
Definition: itkGTestTypedefsAndConstructors.h:44