Examples/IO/RGBImageSeriesReadWrite.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.
 *  You may obtain a copy of the License at
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 *         https://www.apache.org/licenses/LICENSE-2.0.txt
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//  Software Guide : BeginLatex
//
//  RGB images are commonly used for representing data acquired from cryogenic
//  sections, optical microscopy and endoscopy. This example illustrates how
//  to read RGB color images from a set of files containing individual 2D
//  slices in order to compose a 3D color dataset. Then we will save it into a
//  single 3D file, and finally save it again as a set of 2D slices with other
//  names.
//
//  This requires the following headers as shown.
//
//  \index{itk::RGBPixel!Image}
//  \index{RGB!writing Image}
//  \index{RGB!reading Image}
//
//  Software Guide : EndLatex
 
// Software Guide : BeginCodeSnippet
#include "itkRGBPixel.h"
#include "itkImage.h"
#include "itkImageSeriesReader.h"
#include "itkImageSeriesWriter.h"
#include "itkNumericSeriesFileNames.h"
#include "itkPNGImageIO.h"
// Software Guide : EndCodeSnippet
 
 
int
main(int argc, char ** argv)
{
  // Verify the number of parameters in the command line
  if (argc < 4)
  {
    std::cerr << "Usage: " << std::endl;
    std::cerr << argv[0] << "first last  outputRGBImageFile " << std::endl;
    return EXIT_FAILURE;
  }
 
 
  // Software Guide : BeginLatex
  //
  // The \doxygen{RGBPixel} class is templated over the type used to
  // represent each one of the Red, Green and Blue components. A typical
  // instantiation of the RGB image class might be as follows.
  //
  //  \index{itk::RGBPixel!Instantiation}
  //
  // Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  using PixelType = itk::RGBPixel<unsigned char>;
  constexpr unsigned int Dimension = 3;
 
  using ImageType = itk::Image<PixelType, Dimension>;
  // Software Guide : EndCodeSnippet
 
  // Software Guide : BeginLatex
  //
  // The image type is used as a template parameter to instantiate
  // the series reader and the volumetric writer.
  //
  // \index{itk::ImageSeriesReader!RGB Image}
  // \index{itk::ImageFileWriter!RGB Image}
  //
  // Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  using SeriesReaderType = itk::ImageSeriesReader<ImageType>;
  using WriterType = itk::ImageFileWriter<ImageType>;
 
  auto seriesReader = SeriesReaderType::New();
  auto writer = WriterType::New();
  // Software Guide : EndCodeSnippet
 
 
  const unsigned int first = std::stoi(argv[1]);
  const unsigned int last = std::stoi(argv[2]);
 
  const char * outputFilename = argv[3];
 
  // Software Guide : BeginLatex
  //
  // We use a NumericSeriesFileNames class in order to generate the filenames
  // of the slices to be read. Later on in this example we will reuse this
  // object in order to generate the filenames of the slices to be written.
  //
  // Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  using NameGeneratorType = itk::NumericSeriesFileNames;
 
  auto nameGenerator = NameGeneratorType::New();
 
  nameGenerator->SetStartIndex(first);
  nameGenerator->SetEndIndex(last);
  nameGenerator->SetIncrementIndex(1);
 
  nameGenerator->SetSeriesFormat("vwe%03d.png");
  // Software Guide : EndCodeSnippet
 
  //  Software Guide : BeginLatex
  //
  //  The ImageIO object that actually performs the read process
  //  is now connected to the ImageSeriesReader.
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  seriesReader->SetImageIO(itk::PNGImageIO::New());
  // Software Guide : EndCodeSnippet
 
  //  Software Guide : BeginLatex
  //
  //  The filenames of the input slices are taken from the names generator and
  //  passed to the series reader.
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  seriesReader->SetFileNames(nameGenerator->GetFileNames());
  // Software Guide : EndCodeSnippet
 
  // Software Guide : BeginLatex
  //
  // The name of the volumetric output image is passed to the image writer,
  // and we connect the output of the series reader to the input of the
  // volumetric writer.
  //
  // Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  writer->SetFileName(outputFilename);
 
  writer->SetInput(seriesReader->GetOutput());
  // Software Guide : EndCodeSnippet
 
  //  Software Guide : BeginLatex
  //
  //  Finally, execution of the pipeline can be triggered by invoking the
  //  \code{Update()} method in the volumetric writer. This, of course, is
  //  done from inside a try/catch block.
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  try
  {
    writer->Update();
  }
  catch (const itk::ExceptionObject & excp)
  {
    std::cerr << "Error reading the series " << std::endl;
    std::cerr << excp << std::endl;
  }
  // Software Guide : EndCodeSnippet
 
  // Software Guide : BeginLatex
  //
  // We now proceed to save the same volumetric dataset as a set of slices.
  // This is done only to illustrate the process for saving a volume as a
  // series of 2D individual datasets. The type of the series writer must be
  // instantiated taking into account that the input file is a 3D volume and
  // the output files are 2D images.  Additionally, the output of the series
  // reader is connected as input to the series writer.
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  using Image2DType = itk::Image<PixelType, 2>;
 
  using SeriesWriterType = itk::ImageSeriesWriter<ImageType, Image2DType>;
 
  auto seriesWriter = SeriesWriterType::New();
 
  seriesWriter->SetInput(seriesReader->GetOutput());
  // Software Guide : EndCodeSnippet
 
  // Software Guide : BeginLatex
  //
  // We now reuse the filename generator in order to produce the list of
  // filenames for the output series. In this case we just need to modify the
  // format of the filename generator. Then, we pass the list of output
  // filenames to the series writer.
  //
  // Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  nameGenerator->SetSeriesFormat("output%03d.png");
 
  seriesWriter->SetFileNames(nameGenerator->GetFileNames());
  // Software Guide : EndCodeSnippet
 
  // Software Guide : BeginLatex
  //
  // Finally we trigger the execution of the series writer from inside a
  // try/catch block.
  //
  // Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  try
  {
    seriesWriter->Update();
  }
  catch (const itk::ExceptionObject & excp)
  {
    std::cerr << "Error reading the series " << std::endl;
    std::cerr << excp << std::endl;
  }
  // Software Guide : EndCodeSnippet
 
  //  Software Guide : BeginLatex
  //
  //  You may have noticed that apart from the declaration of the
  //  \code{PixelType} there is nothing in this code that is specific to RGB
  //  images. All the actions required to support color images are implemented
  //  internally in the \doxygen{ImageIO} objects.
  //
  // Software Guide : EndLatex
 
  return EXIT_SUCCESS;
}