DGtal  0.9.3beta
geometry/curves/estimation/exampleCurvature.cpp

Example of curvature estimation based on Digital Circular Arc (DCA) estimator.

exampleCurvature.png
Curvature estimated using DCA estimator on a flower shape.
#include <iostream>
#include "DGtal/base/Common.h"
#include "DGtal/kernel/SpaceND.h"
#include "DGtal/kernel/domains/HyperRectDomain.h"
#include "DGtal/topology/KhalimskySpaceND.h"
#include "DGtal/topology/SurfelAdjacency.h"
#include "DGtal/topology/SurfelNeighborhood.h"
#include "DGtal/shapes/Shapes.h"
#include "DGtal/shapes/ShapeFactory.h"
#include "DGtal/shapes/GaussDigitizer.h"
#include "DGtal/geometry/curves/GridCurve.h"
#include "DGtal/geometry/curves/estimation/MostCenteredMaximalSegmentEstimator.h"
#include "DGtal/geometry/curves/StabbingCircleComputer.h"
using namespace std;
using namespace DGtal;
template <typename Shape, typename RealPoint>
bool
estimatorOnShapeDigitization( const string& name,
Shape & aShape,
const RealPoint& low, const RealPoint& up,
double h )
{
using namespace Z2i;
trace.beginBlock ( ( "Curvature estimation on digitization of "
+ name ). c_str() );
// Creates a digitizer on the window (low, up).
dig.attach( aShape ); // attaches the shape.
dig.init( low, up, h );
// The domain size is given by the digitizer
// according to the window and the step.
Domain domain = dig.getDomain();
// Create cellular space
KSpace K;
bool ok = K.init( dig.getLowerBound(), dig.getUpperBound(), true );
if ( ! ok )
{
std::cerr << "[estimatorOnShapeDigitization]"
<< " error in creating KSpace." << std::endl;
}
else
try {
// Extracts shape boundary
SCell bel = Surfaces<KSpace>::findABel( K, dig, 10000 );
// Getting the consecutive surfels of the 2D boundary
std::vector<Point> points;
Surfaces<KSpace>::track2DBoundaryPoints( points, K, SAdj, dig, bel );
// Create GridCurve
GridCurve<KSpace> gridcurve( K );
gridcurve.initFromVector( points );
// Create range of incident points
typedef Range::ConstIterator ClassicIterator;
typedef Range::ConstCirculator CircularIterator;
Range r = gridcurve.getIncidentPointsRange();//building range
// Estimation
std::vector<double> estimations;
if (gridcurve.isOpen())
{
typedef StabbingCircleComputer<ClassicIterator> SegmentComputer;
SegmentComputer sc;
SCEstimator sce;
CurvatureEstimator estimator(sc, sce);
std::cout << "# open grid curve" << endl;
estimator.init( h, r.begin(), r.end() );
estimator.eval( r.begin(), r.end(), std::back_inserter(estimations) );
}
else
{
SegmentComputer sc;
SCEstimator sce;
CurvatureEstimator estimator(sc, sce);
std::cout << "# closed grid curve" << endl;
estimator.init( h, r.c(), r.c() );
estimator.eval( r.c(), r.c(), std::back_inserter(estimations) );
}
// Print (standard output)
std::cout << "# idx kappa" << endl;
unsigned int i = 0;
for ( ClassicIterator it = r.begin(), ite = r.end();
it != ite; ++it, ++i )
{
std::cout << i << " " << estimations.at(i) << std::endl;
}
}
catch ( InputException e )
{
std::cerr << "[estimatorOnShapeDigitization]"
<< " error in finding a bel." << std::endl;
ok = false;
}
trace.emphase() << ( ok ? "Passed." : "Error." ) << endl;
return ok;
}
int main( )
{
trace.beginBlock ( "Example exampleCurvature" );
trace.info() << " Curvature estimation using shape to digitize: flower" << std::endl
<< " with Grid step: 0.01" << std::endl;
// grid step
double h = 0.01;
// shape
string shapeName = "flower";
// parse shape
bool res = true;
typedef Z2i::Space Space;
if (shapeName == "flower")
{
Flower2D<Space> flower( 0.5, 0.5, 5.0, 3.0, 5, 0.3 );
res = estimatorOnShapeDigitization("flower", flower,
RealPoint::diagonal(-10),
RealPoint::diagonal(10),
h);
}
else if (shapeName == "ellipse")
{
Ellipse2D<Space> ellipse( 0.5, 0.5, 5.0, 3.0, 0.3 );
res = estimatorOnShapeDigitization("ellipse", ellipse,
RealPoint::diagonal(-10),
RealPoint::diagonal(10),
h);
}
else if (shapeName == "ball")
{
Ball2D<Space> ball( 0.5, 0.5, 5.0 );
res = estimatorOnShapeDigitization("ball", ball,
RealPoint::diagonal(-10),
RealPoint::diagonal(10),
h);
}
return res;
}
// //