typedef   float           InternalPixelType;
  const     unsigned int    Dimension = 2;
  typedef itk::Image< InternalPixelType, Dimension >  InternalImageType;

  typedef unsigned char                            OutputPixelType;
  typedef itk::Image< OutputPixelType, Dimension > OutputImageType;

  typedef  itk::ImageFileReader< InternalImageType > ReaderType;
  typedef  itk::ImageFileWriter<  OutputImageType  > WriterType;
  typedef  itk::RescaleIntensityImageFilter< 
                               InternalImageType, 
                               OutputImageType >   CastFilterType;

  ReaderType::Pointer reader = ReaderType::New();
  WriterType::Pointer writer = WriterType::New();
  CastFilterType::Pointer caster = CastFilterType::New();

  reader->SetFileName( "Input.bmp" );
  reader->Update();

  typedef itk::ImageRegionConstIterator< InternalImageType > ConstIteratorType;
  typedef itk::ImageRegionIterator< InternalImageType > IteratorType;
  InternalImageType::Pointer outputImage = InternalImageType::New();

  outputImage->SetRegions( reader->GetOutput()->GetLargestPossibleRegion() );
  outputImage->Allocate();

  ConstIteratorType inputIt( reader->GetOutput(), reader->GetOutput()->GetLargestPossibleRegion() );
  IteratorType outputIt( outputImage, reader->GetOutput()->GetLargestPossibleRegion() );
  
  for ( inputIt.GoToBegin(), outputIt.GoToBegin(); !inputIt.IsAtEnd(); ++inputIt, ++outputIt)
  {
	  outputIt.Set( inputIt.Get() + 777); //Add 777 to every pixel.
  }

  caster->SetInput( outputImage ); 
  writer->SetInput( caster->GetOutput() );
  writer->SetFileName("Output.png");
  caster->SetOutputMinimum(   0 );
  caster->SetOutputMaximum( 255 );
  writer->Update();