Laplacian Recursive Gaussian Image Filter

Synopsis

Compute the Laplacian of an image.

Results

Input image

Rescaled Output image [0, 255]

Code

Python

#!/usr/bin/env python

import itk
import argparse

parser = argparse.ArgumentParser(
    description="Laplacian Recursive Gaussian Image Filter."
)
parser.add_argument("input_image")
parser.add_argument("output_image")
args = parser.parse_args()

input_image = itk.imread(args.input_image, pixel_type=itk.F)

output_image = itk.laplacian_recursive_gaussian_image_filter(input_image)

itk.imwrite(output_image, args.output_image)

C++

#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkLaplacianRecursiveGaussianImageFilter.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;

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

  using ReaderType = itk::ImageFileReader<InputImageType>;
  ReaderType::Pointer reader = ReaderType::New();
  reader->SetFileName(argv[1]);
  reader->Update();

  using OutputPixelType = float;
  using OutputImageType = itk::Image<OutputPixelType, Dimension>;

  using FilterType = itk::LaplacianRecursiveGaussianImageFilter<InputImageType, OutputImageType>;
  FilterType::Pointer filter = FilterType::New();
  filter->SetInput(reader->GetOutput());
  filter->Update();

  using WriterType = itk::ImageFileWriter<OutputImageType>;
  WriterType::Pointer writer = WriterType::New();
  writer->SetFileName(argv[2]);
  writer->SetInput(filter->GetOutput());
  try
  {
    writer->Update();
  }
  catch (itk::ExceptionObject & e)
  {
    std::cerr << "Error: " << e << std::endl;
    return EXIT_FAILURE;
  }

  return EXIT_SUCCESS;
}

Classes demonstrated

template<typename TInputImage, typename TOutputImage = TInputImage>
class LaplacianRecursiveGaussianImageFilter : public itk::ImageToImageFilter<TInputImage, TOutputImage>

Computes the Laplacian of Gaussian (LoG) of an image.

Computes the Laplacian of Gaussian (LoG) of an image by convolution with the second derivative of a Gaussian. This filter is implemented using the recursive gaussian filters.

ITK Sphinx Examples:

• All ITK Sphinx Examples

• Compute Laplacian

See itk::LaplacianRecursiveGaussianImageFilter for additional documentation.