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Ellipse

Synopsis

Create ellipse.

Results

Output.png

Code

C++

#include "itkSpatialObjectToImageFilter.h"
#include "itkEllipseSpatialObject.h"
#include "itkImageFileWriter.h"

int
main(int argc, char * argv[])
{
  if (argc != 2)
  {
    std::cerr << "Usage: " << argv[0] << " outputimagefile " << std::endl;
    return EXIT_FAILURE;
  }

  using PixelType = unsigned char;
  constexpr unsigned int Dimension = 2;

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

  using EllipseType = itk::EllipseSpatialObject<Dimension>;

  using SpatialObjectToImageFilterType = itk::SpatialObjectToImageFilter<EllipseType, ImageType>;

  auto imageFilter = SpatialObjectToImageFilterType::New();

  //  The SpatialObjectToImageFilter requires that the user defines the grid
  //  parameters of the output image. This includes the number of pixels along
  //  each dimension, the pixel spacing, image direction and

  ImageType::SizeType size;
  size[0] = 50;
  size[1] = 50;

  imageFilter->SetSize(size);

  ImageType::SpacingType spacing;
  spacing[0] = 100.0 / size[0];
  spacing[1] = 100.0 / size[1];

  imageFilter->SetSpacing(spacing);

  auto                   ellipse = EllipseType::New();
  EllipseType::ArrayType radiusArray;
  radiusArray[0] = 10;
  radiusArray[1] = 20;
  // ellipse->SetRadiusInObjectSpace(  size[0] * 0.2 * spacing[0] );
  ellipse->SetRadiusInObjectSpace(radiusArray);

  // Position the ellipse

  using TransformType = EllipseType::TransformType;

  auto transform = TransformType::New();

  transform->SetIdentity();

  TransformType::OutputVectorType translation;
  translation[0] = size[0] * spacing[0] / 2.0;
  translation[1] = size[1] * spacing[1] / 4.0;
  transform->Translate(translation, false);

  ellipse->SetObjectToParentTransform(transform);

  imageFilter->SetInput(ellipse);

  ellipse->SetDefaultInsideValue(255);

  ellipse->SetDefaultOutsideValue(0);

  imageFilter->SetUseObjectValue(true);

  imageFilter->SetOutsideValue(0);

  try
  {
    imageFilter->Update();
    itk::WriteImage(imageFilter->GetOutput(), argv[1]);
  }
  catch (const itk::ExceptionObject & excp)
  {
    std::cerr << excp << std::endl;
    return EXIT_FAILURE;
  }

  return EXIT_SUCCESS;
}

Classes demonstrated

template<unsigned int TDimension = 3>
class EllipseSpatialObject : public itk::SpatialObject<TDimension>

ITK Sphinx Examples:

• All ITK Sphinx Examples

• Ellipse

See itk::EllipseSpatialObject for additional documentation.