Examples/Filtering/ResampleImageFilter5.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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 *         http://www.apache.org/licenses/LICENSE-2.0.txt
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 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
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//  Software Guide : BeginLatex
//
//  This example illustrates the use of the \doxygen{Similarity2DTransform}. A
//  similarity transform involves rotation, translation and scaling. Since the
//  parameterization of rotations is difficult to get in a generic $ND$ case,
//  a particular implementation is available for $2D$.
//
//
//  Software Guide : EndLatex
 
 
#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkResampleImageFilter.h"
 
 
//  Software Guide : BeginLatex
//
//  The header file of the transform is included below.
//
//  \index{itk::Similarity2DTransform!header}
//
//  Software Guide : EndLatex
 
// Software Guide : BeginCodeSnippet
#include "itkSimilarity2DTransform.h"
// Software Guide : EndCodeSnippet
 
 
int
main(int argc, char * argv[])
{
  if (argc < 5)
  {
    std::cerr << "Usage: " << std::endl;
    std::cerr << argv[0]
              << "  inputImageFile  outputImageFile  degrees  scale"
              << std::endl;
    return EXIT_FAILURE;
  }
 
  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>;
 
  using ReaderType = itk::ImageFileReader<InputImageType>;
  using WriterType = itk::ImageFileWriter<OutputImageType>;
 
  ReaderType::Pointer reader = ReaderType::New();
  WriterType::Pointer writer = WriterType::New();
 
  reader->SetFileName(argv[1]);
  writer->SetFileName(argv[2]);
 
  const double angleInDegrees = std::stod(argv[3]);
  const double scale = std::stod(argv[4]);
 
  using FilterType =
    itk::ResampleImageFilter<InputImageType, OutputImageType>;
 
  FilterType::Pointer filter = FilterType::New();
 
 
  //  Software Guide : BeginLatex
  //
  //  The transform type is instantiated using the coordinate representation
  //  type as the single template parameter.
  //
  //  \index{itk::Similarity2DTransform!instantiation}
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  using TransformType = itk::Similarity2DTransform<double>;
  // Software Guide : EndCodeSnippet
 
 
  //  Software Guide : BeginLatex
  //
  //  A transform object is constructed by calling \code{New()} and passing
  //  the result to a \doxygen{SmartPointer}.
  //
  //  \index{itk::Similarity2DTransform!New()}
  //  \index{itk::Similarity2DTransform!Pointer}
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  TransformType::Pointer transform = TransformType::New();
  // Software Guide : EndCodeSnippet
 
 
  using InterpolatorType =
    itk::LinearInterpolateImageFunction<InputImageType, double>;
  InterpolatorType::Pointer interpolator = InterpolatorType::New();
 
  filter->SetInterpolator(interpolator);
 
  filter->SetDefaultPixelValue(100);
 
 
  //  Software Guide : BeginLatex
  //
  //  The parameters of the output image are taken from the input image.
  //
  //  Software Guide : EndLatex
 
  reader->Update();
  const InputImageType::SpacingType & spacing =
    reader->GetOutput()->GetSpacing();
  const InputImageType::PointType & origin = reader->GetOutput()->GetOrigin();
  const InputImageType::DirectionType & direction =
    reader->GetOutput()->GetDirection();
  InputImageType::SizeType size =
    reader->GetOutput()->GetLargestPossibleRegion().GetSize();
 
  filter->SetOutputOrigin(origin);
  filter->SetOutputSpacing(spacing);
  filter->SetOutputDirection(direction);
  filter->SetSize(size);
 
 
  filter->SetInput(reader->GetOutput());
  writer->SetInput(filter->GetOutput());
 
 
  //  Software Guide : BeginLatex
  //
  //  The Similarity2DTransform allows the user to select the
  //  center of rotation.  This center is used for both rotation and scaling
  //  operations.
  //
  //  \index{itk::Similarity2DTransform!SetRotationCenter()}
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  TransformType::InputPointType rotationCenter;
  rotationCenter[0] = origin[0] + spacing[0] * size[0] / 2.0;
  rotationCenter[1] = origin[1] + spacing[1] * size[1] / 2.0;
  transform->SetCenter(rotationCenter);
  // Software Guide : EndCodeSnippet
 
 
  //  Software Guide : BeginLatex
  //
  //  The rotation is specified with the method \code{SetAngle()}.
  //
  //  \index{itk::Similarity2DTransform!SetAngle()}
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  const double degreesToRadians = std::atan(1.0) / 45.0;
  const double angle = angleInDegrees * degreesToRadians;
  transform->SetAngle(angle);
  // Software Guide : EndCodeSnippet
 
 
  //  Software Guide : BeginLatex
  //
  //  The scale change is defined using the method \code{SetScale()}.
  //  \index{itk::Similarity2DTransform!SetScale()}
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  transform->SetScale(scale);
  // Software Guide : EndCodeSnippet
 
 
  //  Software Guide : BeginLatex
  //
  //  A translation to be applied after the rotation and scaling can be
  //  specified with the method \code{SetTranslation()}.
  //
  //  \index{itk::AffineTransform!Translate()}
  //
  //  Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  TransformType::OutputVectorType translation;
 
  translation[0] = 13.0;
  translation[1] = 17.0;
 
  transform->SetTranslation(translation);
 
  filter->SetTransform(transform);
  // Software Guide : EndCodeSnippet
 
 
  //  Software Guide : BeginLatex
  //
  //  Note that the order in which rotation, scaling and translation are
  //  defined is irrelevant in this transform. This is not the case in the
  //  Affine transform which is very generic and allows different combinations
  //  for initialization. In the Similarity2DTransform class the
  //  rotation and scaling will always be applied before the translation.
  //
  //  \index{itk::Similarity2DTransform!SetScale()}
  //
  //  Software Guide : EndLatex
 
 
  try
  {
    writer->Update();
  }
  catch (const itk::ExceptionObject & excep)
  {
    std::cerr << "Exception catched !" << std::endl;
    std::cerr << excep << std::endl;
  }
 
 
  //  Software Guide : BeginLatex
  //
  //  \begin{figure}
  //  \center
  //  \includegraphics[width=0.44\textwidth]{BrainProtonDensitySliceBorder20}
  //  \includegraphics[width=0.44\textwidth]{ResampleImageFilterOutput11}
  //  \itkcaption[Effect of the Resample filter rotating and scaling an
  //  image]{Effect of the resample filter rotating and scaling an image.}
  //  \label{fig:ResampleImageFilterOutput11}
  //  \end{figure}
  //
  //  Figure \ref{fig:ResampleImageFilterOutput11} shows the effect of this
  //  rotation, translation and scaling on a slice of a brain MRI. The scale
  //  applied for producing this figure was $1.2$ and the rotation angle was
  //  $10^{\circ}$.
  //
  //  Software Guide : EndLatex
 
 
  return EXIT_SUCCESS;
}