Cast an Image to Another Type#

Synopsis#

Cast an Image to another type

Results#

Output image

Output image#

Code#

Python#

#!/usr/bin/env python

import itk
import argparse

parser = argparse.ArgumentParser(description="Cast An Image To Another Type.")
parser.add_argument("input_image")
parser.add_argument("output_image")
args = parser.parse_args()

Dimension = 2
InputPixelType = itk.F
OutputPixelType = itk.UC

InputImageType = itk.Image[InputPixelType, Dimension]
OutputImageType = itk.Image[OutputPixelType, Dimension]

reader = itk.ImageFileReader[InputImageType].New()
reader.SetFileName(args.input_image)

rescaler = itk.RescaleIntensityImageFilter[InputImageType, InputImageType].New()
rescaler.SetInput(reader.GetOutput())
rescaler.SetOutputMinimum(0)
outputPixelTypeMaximum = itk.NumericTraits[OutputPixelType].max()
rescaler.SetOutputMaximum(outputPixelTypeMaximum)

castImageFilter = itk.CastImageFilter[InputImageType, OutputImageType].New()
castImageFilter.SetInput(rescaler.GetOutput())

writer = itk.ImageFileWriter[OutputImageType].New()
writer.SetFileName(args.output_image)
writer.SetInput(castImageFilter.GetOutput())

writer.Update()

C++#

#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkRescaleIntensityImageFilter.h"
#include "itkCastImageFilter.h"

int
main(int argc, char * argv[])
{
  if (argc != 3)
  {
    std::cerr << "Usage: " << std::endl;
    std::cerr << argv[0];
    std::cerr << "<InputFileName> <OutputFileName>";
    std::cerr << std::endl;
    return EXIT_FAILURE;
  }

  constexpr unsigned int Dimension = 2;

  const char * inputImage = argv[1];
  const char * outputImage = argv[2];

  using InputPixelType = float;
  using OutputPixelType = unsigned char;
  using InputImageType = itk::Image<InputPixelType, Dimension>;
  using OutputImageType = itk::Image<OutputPixelType, Dimension>;

  const auto input = itk::ReadImage<InputImageType>(inputImage);

  using RescaleType = itk::RescaleIntensityImageFilter<InputImageType, InputImageType>;
  auto rescale = RescaleType::New();
  rescale->SetInput(input);
  rescale->SetOutputMinimum(0);
  rescale->SetOutputMaximum(itk::NumericTraits<OutputPixelType>::max());

  using FilterType = itk::CastImageFilter<InputImageType, OutputImageType>;
  auto filter = FilterType::New();
  filter->SetInput(rescale->GetOutput());

  try
  {
    itk::WriteImage(filter->GetOutput(), outputImage);
  }
  catch (const itk::ExceptionObject & e)
  {
    std::cerr << "Error: " << e << std::endl;
    return EXIT_FAILURE;
  }

  return EXIT_SUCCESS;
}

Classes demonstrated#

template<typename TInputImage, typename TOutputImage>
class CastImageFilter : public itk::InPlaceImageFilter<TInputImage, TOutputImage>

Casts input pixels to output pixel type.

This filter is templated over the input image type and the output image type.

A typical use is to cast a 

itk::Image<type1, dim>
to a 
itk::Image<type2, dim>

This filter can also be used to cast a 

itk::VectorImage<type1, dim>
to a 
itk::VectorImage<type2, dim>

If you need to perform a dimensionaly reduction, you may want to use the ExtractImageFilter instead of the CastImageFilter.

See

UnaryFunctorImageFilter

See

ExtractImageFilter

ITK Sphinx Examples:

Subclassed by itk::GPUImageToImageFilter< TInputImage, TOutputImage, CastImageFilter< TInputImage, TOutputImage > >

See itk::CastImageFilter for additional documentation.