Examples/IO/ComplexImageReadWrite.cxx

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 *  Copyright NumFOCUS
 *
 *  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 : 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>;
 
  auto reader = ReaderType::New();
  auto 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 (const 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;
}