Set Pixel Value In One Image

Synopsis

This example demonstrates how to set the value of individual pixels in an image.

Results

Output image

Output image

Code

C++

#include "itkImage.h"
#include "itkImageFileWriter.h"

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

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

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

  ImageType::RegionType region;

  ImageType::IndexType start;
  start.Fill(0);

  region.SetIndex(start);

  ImageType::SizeType size;
  size[0] = 200;
  size[1] = 300;

  region.SetSize(size);

  ImageType::Pointer image = ImageType::New();
  image->SetRegions(region);
  image->Allocate();
  image->FillBuffer(itk::NumericTraits<PixelType>::Zero);

  ImageType::IndexType pixelIndex;

  for (ImageType::IndexValueType r = 0; r < 50; r++)
  {
    pixelIndex[0] = 4 * r;
    pixelIndex[1] = 4 * r;

    image->SetPixel(pixelIndex, 128);

    pixelIndex[0] = 4 * r;
    pixelIndex[1] = 200 - 4 * r;

    image->SetPixel(pixelIndex, 255);
  }

  for (ImageType::IndexValueType r = 0; r < 25; r++)
  {
    pixelIndex[0] = 8 * r;
    pixelIndex[1] = 200 + 4 * r;

    image->SetPixel(pixelIndex, 128);

    pixelIndex[0] = 8 * r;
    pixelIndex[1] = 250;

    image->SetPixel(pixelIndex, 180);
  }

  pixelIndex[0] = 95;
  pixelIndex[1] = 150;

  image->SetPixel(pixelIndex, 200);

  pixelIndex[0] = 100;
  pixelIndex[1] = 150;

  image->SetPixel(pixelIndex, 200);

  pixelIndex[0] = 105;
  pixelIndex[1] = 150;

  image->SetPixel(pixelIndex, 200);

  pixelIndex[0] = 100;
  pixelIndex[1] = 155;

  image->SetPixel(pixelIndex, 200);

  pixelIndex[0] = 100;
  pixelIndex[1] = 145;

  image->SetPixel(pixelIndex, 200);

  using WriterType = itk::ImageFileWriter<ImageType>;
  WriterType::Pointer writer = WriterType::New();
  writer->SetInput(image);
  writer->SetFileName(argv[1]);

  try
  {
    writer->Update();
  }
  catch (itk::ExceptionObject & error)
  {
    std::cerr << "Error: " << error << std::endl;
    return EXIT_FAILURE;
  }

  return EXIT_SUCCESS;
}

Classes demonstrated