geometry/curves/greedyAlphaThickDecomposition.cpp

This example shows the greedy decomposition of an noisy contour from the alpha-thick segment primitive with alpha = 4.

See also

Alpha-thick Segment Recognition

Greedy decomposition with alpha-thick segments with alpha = 4

#include <iostream>
#include "ConfigExamples.h"
#include "DGtal/helpers/StdDefs.h"
#include "DGtal/base/Common.h"
#include "DGtal/geometry/curves/AlphaThickSegmentComputer.h"
#include "DGtal/io/boards/Board2D.h"
#include "DGtal/geometry/curves/GreedySegmentation.h"
#include <DGtal/io/readers/GenericReader.h>

using namespace std;
using namespace DGtal;


int main()
{
  trace.beginBlock ( "Example of greedy alpha thick segment  decompotion" );
  
  typedef  std::vector<Z2i::RealPoint>::const_iterator ConstIterator;
  typedef  AlphaThickSegmentComputer<Z2i::RealPoint, ConstIterator > AlphaThickSegmentComputer2D;
  
  Board2D aBoard;
  std::string file = examplesPath + "samples/contourSnoisy.sdp";
  std::vector<Z2i::RealPoint> aContour = PointListReader<Z2i::RealPoint>::getPointsFromFile (file);

  typedef GreedySegmentation<AlphaThickSegmentComputer2D> DecompositionAT;

  // displaying contour
  aBoard << SetMode(aContour[0].className(), "Grid"); 
  std::vector<LibBoard::Point> poly;
  for (unsigned int i = 0; i< aContour.size(); i++)  poly.push_back(LibBoard::Point(aContour[i][0], aContour[i][1]));
  aBoard.setPenColor(DGtal::Color::Gray);
  aBoard.fillPolyline(poly);
  
  // Computing greedy Alpha Thick decomposition.
  aBoard << SetMode("AlphaThickSegment", "BoundingBox");
  
  DecompositionAT theDecomposition(aContour.begin(), aContour.end(), AlphaThickSegmentComputer2D(4)); 

  for ( DecompositionAT::SegmentComputerIterator 
           it = theDecomposition.begin(),
           itEnd = theDecomposition.end();
         it != itEnd; ++it ) 
     {
       aBoard << CustomStyle( (*it).className(), 
                              new CustomPenColor( Color::Blue ) );
       aBoard<< *it;
     } 

  aBoard.saveEPS("greedyAlphaThickDecomposition.eps");

  trace.endBlock();
  return 0;
}
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