shapeGridCurveEstimator.cpp

 
#include <iostream>
#include <fstream>
#include <algorithm>
 
#include "DGtal/base/Common.h"
#include "DGtal/helpers/StdDefs.h"
#include "ConfigExamples.h"
 
//shape and digitizer
#include "DGtal/shapes/Shapes.h"
#include "DGtal/shapes/ShapeFactory.h"
#include "DGtal/shapes/GaussDigitizer.h"
 
//tracking grid curve
#include "DGtal/topology/helpers/Surfaces.h"
#include "DGtal/geometry/curves/GridCurve.h"
 
//length estimation knowing the shape
#include "DGtal/geometry/curves/estimation/TrueGlobalEstimatorOnPoints.h"
#include "DGtal/geometry/curves/estimation/ParametricShapeArcLengthFunctor.h"
//length estimation based on a DSS segmentation
#include "DGtal/geometry/curves/estimation/DSSLengthEstimator.h"
 
#include "DGtal/io/boards/Board2D.h"
 
 
using namespace DGtal;
 
int main()
{
  //shape
  //implicit digitization of a shape of type Flower 
  //into a digital space of type Space
  typedef Flower2D<Z2i::Space> Flower; 
  Flower2D<Z2i::Space> flower(Z2i::Point(0,0), 20, 5, 5, 0);
  
  double h = 1; 
  GaussDigitizer<Z2i::Space,Flower> dig;  
  dig.attach( flower );
  dig.init( flower.getLowerBound()+Z2i::Vector(-1,-1),
            flower.getUpperBound()+Z2i::Vector(1,1), h ); 
  
  //Khalimsky space
  Z2i::KSpace ks;
  ks.init( dig.getLowerBound(), dig.getUpperBound(), true );
  //adjacency (4-connectivity)
  SurfelAdjacency<2> sAdj( true );
 
  //searching for one boundary element
  Z2i::SCell bel = Surfaces<Z2i::KSpace>::findABel( ks, dig, 1000 );
  //tracking
  std::vector<Z2i::Point> boundaryPoints;
  Surfaces<Z2i::KSpace>
    ::track2DBoundaryPoints( boundaryPoints, ks, sAdj, dig, bel );
 
  Z2i::Curve c;
  c.initFromVector( boundaryPoints );  
  
  DGtal::Board2D aBoard;
  aBoard << c; 
  aBoard.saveEPS("DisplayGridCurve1.eps");  
  
  //range of points
  typedef Z2i::Curve::PointsRange Range; 
  Range r = c.getPointsRange(); 
  
  //length estimation
  DSSLengthEstimator< Range::ConstCirculator > DSSlength;
  double length1 = DSSlength.eval(r.c(), r.c(), h);
  trace.info() << "Length (h=" << h << "): " << length1 << std::endl;
 
  typedef ParametricShapeArcLengthFunctor< Flower > Length;
  TrueGlobalEstimatorOnPoints< 
    Range::ConstCirculator, 
    Flower, 
    Length  >  trueLengthEstimator;
  trueLengthEstimator.attach(flower);
  // Note: Not equivalent to eval(r.c(), r.c(), h)
  double trueLength = trueLengthEstimator.eval();
  trace.info() << "ground truth: " << trueLength << std::endl;
 
  //implicit digitization at higher resolution
  h = 0.1; 
  dig.init( flower.getLowerBound()+Z2i::Vector(-1,-1),
            flower.getUpperBound()+Z2i::Vector(1,1), h ); 
  //a greater domain is needed in the Khalimsky space
  ks.init( dig.getLowerBound(), dig.getUpperBound(), true );
  //searching for one boundary element
  bel = Surfaces<Z2i::KSpace>::findABel( ks, dig, 10000 );
  //tracking
  Surfaces<Z2i::KSpace>
    ::track2DBoundaryPoints( boundaryPoints, ks, sAdj, dig, bel );
  //reset grid curve and its points range
  c.initFromVector( boundaryPoints );
  Range r2 = c.getPointsRange(); 
  //estimate length
  double length2 = DSSlength.eval(r2.c(), r2.c(), h);
  trace.info() << "Length (h=" << h << "): " << length2 << std::endl;  
  
  aBoard.clear(); 
  aBoard << c; 
  aBoard.saveEPS("DisplayGridCurve01.eps");  
  
  return 0;
 
}