OrientImageFilter changes the origin of the image

Algorithms
13

Edited: typo

FYI, my test, original image, (BTW it is signed short image, but opened as float to reproduce above test:

r@deb:~/tmp/test038/build$ ./test038 original.nii.gz 
original LPI [86.9175, 90.0284, -101.794]
filter output LPI->RAI [-100.04, -158.669, -101.794]
filter output RAI->LPI [86.9175, 90.0284, -101.794]
re-opened LPI->RAI [-100.04, -158.669, -101.794]
re-opened RAI->LPI [86.9175, 90.0284, -101.794]

Here is code

#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkSpatialOrientation.h"
#include "itkOrientImageFilter.h"

template<typename T> bool orient_filter(
  const typename T::Pointer & image,
  typename T::Pointer & out_image,
  int f)
{
  if (image.IsNull()) return false;
  typedef itk::OrientImageFilter<T,T> OrientImageFilterType;
  typename OrientImageFilterType::Pointer filter = OrientImageFilterType::New();
  try
  {
    filter->SetInput(image);
    filter->UseImageDirectionOn();
    filter->SetDesiredCoordinateOrientation(
      static_cast<itk::SpatialOrientation::ValidCoordinateOrientationFlags>(f));
    filter->Update();
    out_image = filter->GetOutput();
  }
  catch (itk::ExceptionObject & ex)
  {
    std::cout << ex.GetDescription() << std::endl;
    return false;
  }
  if (out_image.IsNotNull()) out_image->DisconnectPipeline();
  else return false;
  return true;
}

int main(int argc, char ** argv)
{
  typedef itk::Image<float, 3> ImageType; 
  typedef itk::ImageFileReader<ImageType> ReaderType;
  typedef itk::ImageFileWriter<ImageType> WriterType;
  ImageType::Pointer inputLPI;
  ImageType::Pointer outputRAI;
  ImageType::Pointer outputLPI;
  ImageType::Pointer reopenedRAI;
  ImageType::Pointer reopenedLPI;
  ReaderType::Pointer reader = ReaderType::New();
  reader->SetFileName(argv[1]);
  try
  {
    reader->Update();
    inputLPI = reader->GetOutput();
  }
  catch (itk::ExceptionObject & ex)
  {
    std::cout << ex.GetDescription() << std::endl;
    return 1;
  }
  std::cout << "original LPI " << inputLPI->GetOrigin()
    << std::endl;
  orient_filter<ImageType>(
    inputLPI,
    outputRAI,
    (int)itk::SpatialOrientation::ITK_COORDINATE_ORIENTATION_RAI);
  std::cout << "filter output LPI->RAI " << outputRAI->GetOrigin()
    << std::endl;
  orient_filter<ImageType>(
    outputRAI,
    outputLPI,
    (int)itk::SpatialOrientation::ITK_COORDINATE_ORIENTATION_LPI);
  std::cout << "filter output RAI->LPI " << outputLPI->GetOrigin()
    << std::endl;
  WriterType::Pointer writer1 = WriterType::New();
  WriterType::Pointer writer2 = WriterType::New();
  writer1->SetInput(outputRAI);
  writer1->SetFileName("outputRAI.nii.gz");
  writer2->SetInput(outputLPI);
  writer2->SetFileName("outputLPI.nii.gz");
  try
  {
    writer1->Update();
    writer2->Update();
  }
  catch (itk::ExceptionObject & ex)
  {
    std::cout << ex.GetDescription() << std::endl;
    return 1;
  }
  ReaderType::Pointer reader1 = ReaderType::New();
  ReaderType::Pointer reader2 = ReaderType::New();
  reader1->SetFileName("outputRAI.nii.gz");
  reader2->SetFileName("outputLPI.nii.gz");
  try
  {
    reader1->Update();
    reader2->Update();
    reopenedRAI = reader1->GetOutput();
    reopenedLPI = reader2->GetOutput();
  }
  catch (itk::ExceptionObject & ex)
  {
    std::cout << ex.GetDescription() << std::endl;
    return 1;
  }
  std::cout << "re-opened LPI->RAI " << reopenedRAI->GetOrigin()
    << std::endl;
  std::cout << "re-opened RAI->LPI n" << reopenedLPI->GetOrigin()
    << std::endl;
  return 0;
}

nnn