Problem in adding two images

Beginner Questions
1

Hi,
I used the following code to add two attached images; however, it does not work. Does any one know the problem with that? it set the startx and starty to 0.

#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkPasteImageFilter.h"

int
main(int argc, char * argv[])
{
  if (argc != 6)
  {
    std::cerr << "Usage: " << std::endl;
    std::cerr << argv[0];
    std::cerr << " <SourceFileName> <DestinationFileName> <OutputFileName> <start x> <start y>";
    std::cerr << std::endl;
    return EXIT_FAILURE;
  }

  const char * sourceFileName = argv[1];
  const char * destinationFileName = argv[2];
  const char * outputFileName = argv[3];

  int startX = std::stoi(argv[4]);
  int startY = std::stoi(argv[5]);
  

  constexpr unsigned int Dimension = 2;

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

  ImageType::IndexType index;
  index[0] = startX;
  index[1] = startY;
  
  using ReaderType = itk::ImageFileReader<ImageType>;
  ReaderType::Pointer sourceReader = ReaderType::New();
  sourceReader->SetFileName(sourceFileName);
  sourceReader->Update();

  ReaderType::Pointer destinationReader = ReaderType::New();
  destinationReader->SetFileName(destinationFileName);

  using FilterType = itk::PasteImageFilter<ImageType, ImageType>;
  FilterType::Pointer filter = FilterType::New();
  filter->SetSourceImage(sourceReader->GetOutput());
  filter->SetSourceRegion(sourceReader->GetOutput()->GetLargestPossibleRegion());
  filter->SetDestinationImage(destinationReader->GetOutput());
  filter->SetDestinationIndex(index);

  using WriterType = itk::ImageFileWriter<ImageType>;
  WriterType::Pointer writer = WriterType::New();
  writer->SetFileName(outputFileName);
  writer->SetInput(filter->GetOutput());
  try
  {
    writer->Update();
  }
  catch (itk::ExceptionObject & error)
  {
    std::cerr << "Error: " << error << std::endl;
    return EXIT_FAILURE;
  }

  return EXIT_SUCCESS;
}

Human01-projection6.nrrd (46.0 KB) input13.nrrd (46.0 KB)

2

Paste filter overwrites the image, you need AddImageFilter.

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