Computer Magnitude in Vector Image to Make Magnitude Image#
Synopsis#
Compute the magnitude of each pixel in a vector image to produce a magnitude image
Results#
Yinyang.png#
output.png#
Code#
C++#
#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkRescaleIntensityImageFilter.h"
#include "itkVectorImage.h"
#include "itkVectorMagnitudeImageFilter.h"
int
main(int argc, char * argv[])
{
// Verify command line arguments
if (argc < 3)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImageFile outputImageFile" << std::endl;
return EXIT_FAILURE;
}
// Parse command line arguments
std::string inputFileName = argv[1];
std::string outputFileName = argv[2];
// Setup types
using VectorImageType = itk::VectorImage<float, 2>;
using UnsignedCharImageType = itk::Image<unsigned char, 2>;
const auto input = itk::ReadImage<VectorImageType>(inputFileName);
using VectorMagnitudeFilterType = itk::VectorMagnitudeImageFilter<VectorImageType, UnsignedCharImageType>;
auto magnitudeFilter = VectorMagnitudeFilterType::New();
magnitudeFilter->SetInput(input);
// To write the magnitude image file, we should rescale the gradient values
// to a reasonable range
using rescaleFilterType = itk::RescaleIntensityImageFilter<UnsignedCharImageType, UnsignedCharImageType>;
auto rescaler = rescaleFilterType::New();
rescaler->SetOutputMinimum(0);
rescaler->SetOutputMaximum(255);
rescaler->SetInput(magnitudeFilter->GetOutput());
itk::WriteImage(rescaler->GetOutput(), outputFileName);
return EXIT_SUCCESS;
}
Classes demonstrated#
-
template<typename TInputImage, typename TOutputImage>
class VectorMagnitudeImageFilter : public itk::UnaryGeneratorImageFilter<TInputImage, TOutputImage> Take an image of vectors as input and produce an image with the magnitude of those vectors.
The filter expects the input image pixel type to be a vector and the output image pixel type to be a scalar.
This filter assumes that the PixelType of the input image is a VectorType that provides a GetNorm() method.
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