tutorial-examples/freemanChainFromImage.cpp

A simple example to show how to extract the set of boundary contours obtained from the image level set. This programm outputs this image:

#include "DGtal/base/Common.h"
#include "DGtal/helpers/StdDefs.h"
#include "ConfigExamples.h"

#include "DGtal/io/readers/PNMReader.h"
#include "DGtal/images/imagesSetsUtils/SetFromImage.h"

#include "DGtal/topology/helpers/Surfaces.h"
#include "DGtal/geometry/curves/FreemanChain.h"

#include "DGtal/io/boards/Board2D.h"
#include "DGtal/io/colormaps/GradientColorMap.h"
#include "DGtal/io/Color.h"

int main()
{

  typedef DGtal::ImageContainerBySTLVector< Z2i::Domain, unsigned char> Image;
  std::string filename =  examplesPath + "samples/circleR10modif.pgm";
  Image image = DGtal::PNMReader<Image>::importPGM(filename); 
  
  Z2i::KSpace ks;
  ks.init( image.domain().lowerBound(), image.domain().upperBound(), true );

  Z2i::DigitalSet set2d (image.domain());
  SetPredicate<Z2i::DigitalSet> set2dPredicate( set2d );
  SetFromImage<Z2i::DigitalSet>::append<Image>(set2d, image, 1, 255);


  Board2D aBoard;
  aBoard << set2d;
  aBoard << image.domain();  

  SurfelAdjacency<2> sAdj( true );

  std::vector< std::vector< Z2i::Point >  >  vectContoursBdryPointels;
  Surfaces<Z2i::KSpace>::extractAllPointContours4C( vectContoursBdryPointels,
                ks, set2dPredicate, sAdj );  
  

  GradientColorMap<int> cmap_grad( 0, (const int)vectContoursBdryPointels.size() );
  cmap_grad.addColor( Color( 50, 50, 255 ) );
  cmap_grad.addColor( Color( 255, 0, 0 ) );
  cmap_grad.addColor( Color( 255, 255, 10 ) );
  cmap_grad.addColor( Color( 25, 255, 255 ) );
  cmap_grad.addColor( Color( 255, 25, 255 ) );
  cmap_grad.addColor( Color( 25, 25, 25 ) );
  
  for(unsigned int i=0; i<vectContoursBdryPointels.size(); i++){
    //  Constructing and displaying FreemanChains from contours. 
    FreemanChain<Z2i::Integer> fc (vectContoursBdryPointels.at(i));    
    aBoard << SetMode( fc.className(), "InterGrid" );
    aBoard<< CustomStyle( fc.className(), 
            new CustomColors(  cmap_grad(i),  Color::None ) );        
    aBoard << fc;
  }   

  aBoard.saveEPS("freemanChainFromImage.eps");
  return 0;
}