DGtal  0.9.4beta
tutorial-examples/AreaSurfaceEstimation-final.cpp

Example of tutorial 4: Surface area estimation

See also
Tutorial: Surface area estimation
#include "DGtal/shapes/parametric/Ball3D.h"
#include "DGtal/shapes/GaussDigitizer.h"
#include "DGtal/topology/LightImplicitDigitalSurface.h"
#include "DGtal/topology/DigitalSurface.h"
#include "DGtal/graph/DepthFirstVisitor.h"
#include "DGtal/graph/GraphVisitorRange.h"
#include "DGtal/geometry/surfaces/estimation/IIGeometricFunctors.h"
#include "DGtal/geometry/surfaces/estimation/IntegralInvariantCovarianceEstimator.h"
using namespace DGtal;
int main( int argc, char** argv )
{
const double h = 1;
const double radiusBall = 12.0;
const double radiusII = 6;
const double trueAreaSurface = 4.0*M_PI*radiusBall*radiusBall;
trace.beginBlock( "Make parametric shape..." );
typedef Ball3D< Z3i::Space > Shape;
Z3i::RealPoint center( 0.0, 0.0, 0.0 );
Shape ball( center, radiusBall );
trace.beginBlock( "Make digital shape..." );
DigitalShape digitalBall;
digitalBall.attach( ball );
digitalBall.init( ball.getLowerBound() - Z3i::RealPoint( 1.0, 1.0, 1.0 ),
ball.getUpperBound() + Z3i::RealPoint( 1.0, 1.0, 1.0 ),
h );
Domain domain = digitalBall.getDomain();
Z3i::KSpace kspace;
kspace.init( domain.lowerBound(), domain.upperBound(), true );
trace.beginBlock( "Make digital surface..." );
typedef GraphVisitorRange::ConstIterator SurfelConstIterator;
typedef Z3i::KSpace::Surfel Surfel;
Surfel bel = Surfaces< Z3i::KSpace >::findABel( kspace, digitalBall, 500 );
LightDigitalSurface lightDigitalSurface( kspace, digitalBall, surfelAdjacency, bel );
DigitalSurface digitalSurface( lightDigitalSurface );
GraphVisitorRange graphVisitorRange( new DepthFirstVisitor( digitalSurface, *digitalSurface.begin() ) );
SurfelConstIterator sbegin = graphVisitorRange.begin();
SurfelConstIterator send = graphVisitorRange.end();
std::vector< Surfel > v_border;
while( sbegin != send )
{
v_border.push_back( *sbegin );
++sbegin;
}
trace.beginBlock( "Computation with normal estimation ..." );
typedef IIGeometricFunctors::IINormalDirectionFunctor< Z3i::Space > NormalFunctor;
NormalFunctor normalFunctor;
IINormalEstimator normalEstimator( normalFunctor );
normalEstimator.attach( kspace, digitalBall );
normalEstimator.setParams( radiusII / h );
normalEstimator.init( h, v_border.begin(), v_border.end() );
double areaSurfaceEstimated = 0.0;
for( unsigned int i_position = 0; i_position < v_border.size(); ++i_position )
{
Z3i::RealPoint normalEstimated = normalEstimator.eval( &(v_border[i_position]) );
Z3i::RealPoint normalSurfel = kspace.sKCoords( kspace.sDirectIncident( v_border[i_position], kspace.sOrthDir( v_border[i_position] ))) - kspace.sKCoords( v_border[i_position] );
normalEstimated = normalEstimated.getNormalized();
areaSurfaceEstimated += std::abs( normalEstimated.dot( normalSurfel )) * h * h;
}
trace.info() << "Area Surface estimated : " << areaSurfaceEstimated << std::endl;
trace.info() << "True areaSurface : " << trueAreaSurface << std::endl;
trace.info() << "Ratio : " << areaSurfaceEstimated / trueAreaSurface << std::endl;
return 0;
}