Linearly Interpolate Position in Image

Synopsis

Linearly interpolate a position in an image.

Results

Output:

Value at 1.3: 13

Code

C++

#include "itkImage.h"
#include "itkContinuousIndex.h"
#include "itkLinearInterpolateImageFunction.h"

using ImageType = itk::Image<unsigned char, 1>;

static void
CreateImage(ImageType::Pointer image);

int
main(int, char *[])
{
  ImageType::Pointer image = ImageType::New();
  CreateImage(image);

  itk::ContinuousIndex<double, 1> pixel;
  pixel[0] = 1.3;

  itk::LinearInterpolateImageFunction<ImageType, double>::Pointer interpolator =
    itk::LinearInterpolateImageFunction<ImageType, double>::New();
  interpolator->SetInputImage(image);

  std::cout << "Value at 1.3: " << interpolator->EvaluateAtContinuousIndex(pixel) << std::endl;

  return EXIT_SUCCESS;
}


void
CreateImage(ImageType::Pointer image)
{
  // Create a 1D image
  ImageType::RegionType region;
  ImageType::IndexType  start;
  start[0] = 0;

  ImageType::SizeType size;
  size[0] = 10;

  region.SetSize(size);
  region.SetIndex(start);

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

  for (unsigned int i = 0; i < 10; i++)
  {
    ImageType::IndexType pixelIndex;
    pixelIndex[0] = i;

    image->SetPixel(pixelIndex, i * 10);
  }
}

Classes demonstrated

template<typename TInputImage, typename TCoordRep = double>
class LinearInterpolateImageFunction : public itk::InterpolateImageFunction<TInputImage, TCoordRep>

Linearly interpolate an image at specified positions.

LinearInterpolateImageFunction linearly interpolates image intensity at a non-integer pixel position. This class is templated over the input image type and the coordinate representation type (e.g. float or double).

This function works for N-dimensional images.

This function works for images with scalar and vector pixel types, and for images of type VectorImage.

See

VectorLinearInterpolateImageFunction

ITK Sphinx Examples:

• All ITK Sphinx Examples

• Linearly Interpolate Position In Image

See itk::LinearInterpolateImageFunction for additional documentation.