Find Max and Min in Image

Synopsis

Find the minimum and maximum value (and the position of the value) in an image.

Results

Yingyang.png

Output Image

Code

C++

#include "itkImage.h"
#include "itkImageFileWriter.h"
#include "itkMinimumMaximumImageCalculator.h"
#include "itkImageFileReader.h"

#include <itkImageToVTKImageFilter.h>

#include "vtkVersion.h"
#include "vtkImageViewer.h"
#include "vtkImageMapper3D.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkSmartPointer.h"
#include "vtkImageActor.h"
#include "vtkInteractorStyleImage.h"
#include "vtkRenderer.h"
#include "vtkSphereSource.h"
#include "vtkPolyDataMapper.h"
#include "vtkActor.h"
#include "vtkProperty.h"

using ImageType = itk::Image<unsigned char, 2>;

int
main(int argc, char * argv[])
{
  if (argc < 2)
  {
    std::cerr << "Required: filename" << std::endl;

    return EXIT_FAILURE;
  }
  std::string inputFilename = argv[1];

  using ReaderType = itk::ImageFileReader<ImageType>;
  ReaderType::Pointer reader = ReaderType::New();

  reader->SetFileName(inputFilename.c_str());
  reader->Update();

  using ImageCalculatorFilterType = itk::MinimumMaximumImageCalculator<ImageType>;

  ImageCalculatorFilterType::Pointer imageCalculatorFilter = ImageCalculatorFilterType::New();
  imageCalculatorFilter->SetImage(reader->GetOutput());
  imageCalculatorFilter->Compute();

  using ConnectorType = itk::ImageToVTKImageFilter<ImageType>;
  ConnectorType::Pointer originalConnector = ConnectorType::New();

  originalConnector->SetInput(reader->GetOutput());

  vtkSmartPointer<vtkImageActor> originalActor = vtkSmartPointer<vtkImageActor>::New();
#if VTK_MAJOR_VERSION <= 5
  originalActor->SetInput(originalConnector->GetOutput());
#else
  originalConnector->Update();
  originalActor->GetMapper()->SetInputData(originalConnector->GetOutput());
#endif

  vtkSmartPointer<vtkSphereSource> minimumSphereSource = vtkSmartPointer<vtkSphereSource>::New();
  ImageType::IndexType             minimumLocation = imageCalculatorFilter->GetIndexOfMinimum();
  minimumSphereSource->SetCenter(minimumLocation[0], minimumLocation[1], 0);
  minimumSphereSource->SetRadius(10);

  vtkSmartPointer<vtkPolyDataMapper> minimumMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
  minimumMapper->SetInputConnection(minimumSphereSource->GetOutputPort());
  vtkSmartPointer<vtkActor> minimumActor = vtkSmartPointer<vtkActor>::New();
  minimumActor->SetMapper(minimumMapper);
  minimumActor->GetProperty()->SetColor(0, 1, 0);

  vtkSmartPointer<vtkSphereSource> maximumSphereSource = vtkSmartPointer<vtkSphereSource>::New();
  maximumSphereSource->SetRadius(10);
  ImageType::IndexType maximumLocation = imageCalculatorFilter->GetIndexOfMaximum();
  maximumSphereSource->SetCenter(maximumLocation[0], maximumLocation[1], 0);

  vtkSmartPointer<vtkPolyDataMapper> maximumMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
  maximumMapper->SetInputConnection(maximumSphereSource->GetOutputPort());
  vtkSmartPointer<vtkActor> maximumActor = vtkSmartPointer<vtkActor>::New();
  maximumActor->SetMapper(maximumMapper);
  maximumActor->GetProperty()->SetColor(1, 0, 0);


  // Visualize
  vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();

  vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
  interactor->SetRenderWindow(renderWindow);

  vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(renderer);

  // Add the sphere to the left and the cube to the right
  renderer->AddActor(originalActor);
  renderer->AddActor(minimumActor);
  renderer->AddActor(maximumActor);

  renderer->ResetCamera();

  renderWindow->Render();

  vtkSmartPointer<vtkInteractorStyleImage> style = vtkSmartPointer<vtkInteractorStyleImage>::New();
  interactor->SetInteractorStyle(style);

  interactor->Start();

  return EXIT_SUCCESS;
}

Classes demonstrated

template<typename TInputImage>
class MinimumMaximumImageCalculator : public itk::Object

Computes the minimum and the maximum intensity values of an image.

This calculator computes the minimum and the maximum intensity values of an image. It is templated over input image type. If only Maximum or Minimum value is needed, just call ComputeMaximum() (ComputeMinimum()) otherwise Compute() will compute both.

ITK Sphinx Examples:

• All ITK Sphinx Examples

• Find Max And Min In Image

• Multi-thread Oil Painting

See itk::MinimumMaximumImageCalculator for additional documentation.