Compose Vector From Three Scalar Images#

Synopsis#

Compose a vector image (with 3 components) from three scalar images.

Results#

Output:

1.2
[1.2, 1.2, 1.2]

Code#

C++#

#include "itkImageAdaptor.h"
#include "itkImageRegionIterator.h"
#include "itkComposeImageFilter.h"

using VectorImageType = itk::Image<itk::CovariantVector<float, 3>, 2>;
using ScalarImageType = itk::Image<float, 2>;

static void
CreateImage(ScalarImageType::Pointer image);

int
main()
{
  auto image = ScalarImageType::New();
  CreateImage(image);

  using ComposeCovariantVectorImageFilterType = itk::ComposeImageFilter<ScalarImageType, VectorImageType>;
  auto composeFilter = ComposeCovariantVectorImageFilterType::New();

  composeFilter->SetInput1(image);
  composeFilter->SetInput2(image);
  composeFilter->SetInput3(image);
  composeFilter->Update();

  itk::Index<2> index;
  index.Fill(0);

  std::cout << image->GetPixel(index) << std::endl;

  std::cout << composeFilter->GetOutput()->GetPixel(index) << std::endl;

  return EXIT_SUCCESS;
}

void
CreateImage(ScalarImageType::Pointer image)
{
  ScalarImageType::IndexType start;
  start.Fill(0);

  ScalarImageType::SizeType size;
  size.Fill(2);

  ScalarImageType::RegionType region;
  region.SetSize(size);
  region.SetIndex(start);

  image->SetRegions(region);
  image->Allocate();

  itk::ImageRegionIterator<ScalarImageType> imageIterator(image, image->GetLargestPossibleRegion());

  while (!imageIterator.IsAtEnd())
  {
    imageIterator.Set(1.2);

    ++imageIterator;
  }
}

Classes demonstrated#

template<typename TInputImage, typename TOutputImage = VectorImage<typename TInputImage::PixelType, TInputImage::ImageDimension>> class ComposeImageFilter : public itk::ImageToImageFilter<TInputImage, TOutputImage>

ComposeImageFilter combine several scalar images into a multicomponent image.

ComposeImageFilter combine several scalar images into an itk::Image of vector pixel (itk::Vector, itk::RGBPixel, …), of std::complex pixel, or in an itk::VectorImage.

Inputs and Usage

filter->SetInput( 0, image0 );
filter->SetInput( 1, image1 );
...
filter->Update();
itk::VectorImage< PixelType, dimension >::Pointer = filter->GetOutput();