Examples/IO/ComplexImageReadWrite.cxx

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//  Software Guide : BeginLatex
//
//  This example illustrates how to read and write an image of pixel type
//  \code{std::complex}. The complex type is defined as an integral part of the
//  C++ language. The characteristics of the type are specified in the C++
//  standard document in Chapter 26 "Numerics Library", page 565, in particular
//  in section 26.2~\cite{CPPStandard1998}.
//
//  We start by including the headers of the complex class, the image, and the
//  reader and writer classes.
//
//  \index{itk::ImageFileRead!Complex images}
//  \index{itk::ImageFileWrite!Complex images}
//  \index{Complex images!Instantiation}
//  \index{Complex images!Reading}
//  \index{Complex images!Writing}
//
//  Software Guide : EndLatex


// Software Guide : BeginCodeSnippet
#include <complex>
#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
// Software Guide : EndCodeSnippet


int main( int argc, char * argv [] )
{

  // Verify the number of parameters in the command line
  if( argc < 3 )
    {
    std::cerr << "Usage: " << std::endl;
    std::cerr << argv[0] << " inputImageFile  outputImageFile " << std::endl;
    return EXIT_FAILURE;
    }

// Software Guide : BeginLatex
//
// The image dimension and pixel type must be declared. In this case we use the
// \code{std::complex<>} as the pixel type. Using the dimension and pixel type
// we proceed to instantiate the image type.
//
// Software Guide : EndLatex


// Software Guide : BeginCodeSnippet
  constexpr unsigned int Dimension = 2;

  using PixelType = std::complex< float >;
  using ImageType = itk::Image< PixelType, Dimension >;
// Software Guide : EndCodeSnippet


// Software Guide : BeginLatex
//
// The image file reader and writer types are instantiated using the image
// type. We can then create objects for both of them.
//
// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet
  using ReaderType = itk::ImageFileReader< ImageType >;
  using WriterType = itk::ImageFileWriter< ImageType >;

  ReaderType::Pointer reader = ReaderType::New();
  WriterType::Pointer writer = WriterType::New();
// Software Guide : EndCodeSnippet


// Software Guide : BeginLatex
//
// File names should be provided for both the reader and the writer. In this
// particular example we take those file names from the command line arguments.
//
// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet
  reader->SetFileName( argv[1] );
  writer->SetFileName( argv[2] );
// Software Guide : EndCodeSnippet

// Software Guide : BeginLatex
//
// Here we simply connect the output of the reader as input to the writer.
// This simple program could be used for converting complex images from one
// file format to another.
//
// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet
  writer->SetInput( reader->GetOutput() );
// Software Guide : EndCodeSnippet

// Software Guide : BeginLatex
//
// The execution of this short pipeline is triggered by invoking the
// \code{Update()} method of the writer. This invocation must be placed inside
// a try/catch block since its execution may result in exceptions being thrown.
//
// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet
  try
    {
    writer->Update();
    }
  catch( itk::ExceptionObject & err )
    {
    std::cerr << "ExceptionObject caught !" << std::endl;
    std::cerr << err << std::endl;
    return EXIT_FAILURE;
    }
  // Software Guide : EndCodeSnippet

  // Software Guide : BeginLatex
  //
  // For a more interesting use of this code, you may want to add a filter in
  // between the reader and the writer and perform any complex image to complex
  // image operation. A practical application of this code is presented in
  // section~\ref{sec:FrequencyDomain} in the context of Fourier analysis.
  //
  // Software Guide : EndLatex

  return EXIT_SUCCESS;
}