Examples/Filtering/ResampleImageFilter9.cxx

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 *
 *  Copyright Insight Software Consortium
 *
 *  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,
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//  Software Guide : BeginLatex
//
//  Resampling can also be performed in multi-component images.
//  This example compares nearest neighbor resampling using the Nearest
//  neighbor and the linear interpolators for vector images.
//
//  Try
//    ResampleImageFilter9 Examples/Data/VisibleWomanEyeSlice.png
//        SliceNearestNeighbor.png SliceLinear.png
//
//  \index{itk::VectorResampleImageFilter!Image internal transform}
//
//  Software Guide : EndLatex


#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkVectorResampleImageFilter.h"
#include "itkIdentityTransform.h"
#include "itkVectorNearestNeighborInterpolateImageFunction.h"
#include "itkLinearInterpolateImageFunction.h"
#include "itkRGBPixel.h"


int main( int argc, char * argv[] )
{
  if( argc < 4 )
    {
    std::cerr << "Usage: " << std::endl;
    std::cerr << argv[0] <<
      "  inputImageFile  outputImageFile_NearestNeighbor" <<
      "  outputImageFile_Linear " << std::endl;
    return EXIT_FAILURE;
    }

  constexpr unsigned int Dimension = 2;
  using PixelComponentType = unsigned char;
  using PixelType = itk::RGBPixel< PixelComponentType >;

  using ImageType = itk::Image< PixelType,  Dimension >;


  using ReaderType = itk::ImageFileReader< ImageType >;
  using WriterType = itk::ImageFileWriter< ImageType >;

  ReaderType::Pointer reader = ReaderType::New();
  WriterType::Pointer writerNearest = WriterType::New(); // writer for nearest neighbor
  WriterType::Pointer writerLinear = WriterType::New(); // writer for linear

  reader->SetFileName( argv[1] );
  writerNearest->SetFileName( argv[2] );
  writerLinear->SetFileName( argv[3] );

  using FilterType = itk::VectorResampleImageFilter<
                            ImageType, ImageType >;

  FilterType::Pointer nearestFilter = FilterType::New();
  FilterType::Pointer linearFilter = FilterType::New();

  //Interpolators
  using NearestInterpolatorType = itk::VectorNearestNeighborInterpolateImageFunction<
                       ImageType, double >;
  NearestInterpolatorType::Pointer interpolatorNearest = NearestInterpolatorType::New();

  using LinearInterpolatorType = itk::VectorLinearInterpolateImageFunction<
                       ImageType, double >;
  LinearInterpolatorType::Pointer interpolatorLinear = LinearInterpolatorType::New();

  nearestFilter->SetInterpolator( interpolatorNearest );
  linearFilter->SetInterpolator( interpolatorLinear );

  using TransformType = itk::IdentityTransform< double, Dimension >;
  TransformType::Pointer transform = TransformType::New();

  nearestFilter->SetTransform( transform );
  linearFilter->SetTransform( transform );

  // Software Guide : BeginCodeSnippet
  PixelType defaultValue;
  defaultValue.Fill(50);
  nearestFilter->SetDefaultPixelValue( defaultValue );
  linearFilter->SetDefaultPixelValue( defaultValue );
  // Software Guide : EndCodeSnippet


  // Software Guide : BeginCodeSnippet
  ImageType::SpacingType spacing;
  spacing[0] = .35; // pixel spacing in millimeters along X
  spacing[1] = .35; // pixel spacing in millimeters along Y

  nearestFilter->SetOutputSpacing( spacing );
  linearFilter->SetOutputSpacing( spacing );
  // Software Guide : EndCodeSnippet


  // Software Guide : BeginCodeSnippet
  ImageType::PointType origin;
  origin[0] = 0.4;  // X space coordinate of origin
  origin[1] = 0.4;  // Y space coordinate of origin
  nearestFilter->SetOutputOrigin( origin );
  linearFilter->SetOutputOrigin( origin );
  // Software Guide : EndCodeSnippet


  // Software Guide : BeginCodeSnippet
  ImageType::DirectionType direction;
  direction.SetIdentity();
  nearestFilter->SetOutputDirection( direction );
  linearFilter->SetOutputDirection( direction );
  // Software Guide : EndCodeSnippet


  ImageType::SizeType   size;

  size[0] = 300;  // number of pixels along X
  size[1] = 300;  // number of pixels along Y

  nearestFilter->SetSize( size );
  linearFilter->SetSize( size );

  nearestFilter->SetInput( reader->GetOutput() );
  linearFilter->SetInput( reader->GetOutput() );
  writerNearest->SetInput( nearestFilter->GetOutput() );
  writerLinear->SetInput( linearFilter->GetOutput() );


  try
    {
    writerNearest->Update();
    }
  catch( itk::ExceptionObject & excp )
    {
    std::cerr << "Exception thrown " << std::endl;
    std::cerr << excp << std::endl;
    }

  try
    {
    writerLinear->Update();
    }
  catch( itk::ExceptionObject & excp )
    {
    std::cerr << "Exception thrown " << std::endl;
    std::cerr << excp << std::endl;
    }

  return EXIT_SUCCESS;

}