DGtal: DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder

Aim: Implements a functor to detect feature points from normal tensor voting strategy. More...

#include <DGtal/geometry/surfaces/estimation/estimationFunctors/TensorVotingFeatureExtraction.h>

Public Types
typedef TSurfel	Surfel

typedef TEmbedder	SCellEmbedder

typedef SCellEmbedder::RealPoint	RealPoint

typedef double	Quantity

Public Member Functions
	TensorVotingFeatureExtraction (ConstAlias< SCellEmbedder > anEmbedder, const double h)

void	pushSurfel (const Surfel &aSurf, const double aDistance)

Quantity	eval ()

void	reset ()

Private Attributes
bool	myFirstSurfel
	First surfel flag. More...

const SCellEmbedder *	myEmbedder
	Alias of the geometrical embedder. More...

double	myH

RealPoint	myReceiver
	Receiver (embedding of the starting surfel) More...

SimpleMatrix< double, 3, 3 >	myAccum
	Covariance accumulator. More...

SimpleMatrix< double, 3, 3 >	myId

SimpleMatrix< double, 3, 3 >	myVote

double	myArea
	Convolution kernel area. More...

Detailed Description

template<typename TSurfel, typename TEmbedder>
class DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >

Aim: Implements a functor to detect feature points from normal tensor voting strategy.

Description of template class 'TensorVotingFeatureExtraction'

More precisely, the functor accumulates tensor votes \(I - vv^T/\|vv^T\|\) for each surfel added during the scan ( \(v\) being the vector from the center of the neighborhood to the added surfel). Then, the eval() method returns the ratio \(\frac{\lambda_1+\lambda_2}{\lambda_3}\) of the eigenvalues ( \( \lambda_1\leq\lambda_2\leq\lambda_3\)) of the accumulated tensor votes.

(see [98])

model of concepts::CLocalEstimatorFromSurfelFunctor

Template Parameters

TSurfel	type of surfels
TEmbedder	type of functors which embed surfel to \( \mathbb{R}^3\)

Definition at line 81 of file TensorVotingFeatureExtraction.h.

Member Typedef Documentation

◆ Quantity

template<typename TSurfel , typename TEmbedder >

typedef double DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::Quantity

Definition at line 88 of file TensorVotingFeatureExtraction.h.

◆ RealPoint

template<typename TSurfel , typename TEmbedder >

typedef SCellEmbedder::RealPoint DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::RealPoint

Definition at line 87 of file TensorVotingFeatureExtraction.h.

◆ SCellEmbedder

template<typename TSurfel , typename TEmbedder >

typedef TEmbedder DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::SCellEmbedder

Definition at line 86 of file TensorVotingFeatureExtraction.h.

◆ Surfel

template<typename TSurfel , typename TEmbedder >

typedef TSurfel DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::Surfel

Definition at line 85 of file TensorVotingFeatureExtraction.h.

Constructor & Destructor Documentation

◆ TensorVotingFeatureExtraction()

template<typename TSurfel , typename TEmbedder >

DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::TensorVotingFeatureExtraction	(	ConstAlias< SCellEmbedder >	anEmbedder,
		const double	h
	)

inline

Constructor.

Parameters

anEmbedder	embedder to map surfel to R^n.
h	grid step

Definition at line 96 of file TensorVotingFeatureExtraction.h.

                                                    :
         myEmbedder(&anEmbedder), myH(h)
       {
         myId.identity();
         myArea = 0.0;
         myFirstSurfel = true;
         myAccum.constant(0.0);
       }

References DGtal::SimpleMatrix< TComponent, TM, TN >::constant(), DGtal::SimpleMatrix< TComponent, TM, TN >::identity(), DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myAccum, DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myArea, DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myFirstSurfel, and DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myId.

Member Function Documentation

◆ eval()

template<typename TSurfel , typename TEmbedder >

Quantity DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::eval ( )

inline

Evaluate the feature score.

I.e. (l_1+l_2)/l_3 of the tensor eigenvalues (l_1<l_2<l_3).

Returns: the feature score

Definition at line 154 of file TensorVotingFeatureExtraction.h.

       {
         SimpleMatrix<double, 3, 3> eigenvectors;
         RealPoint eigenvalues;
  
         myAccum /= myArea;
         EigenDecomposition<3, double>::getEigenDecomposition( myAccum, eigenvectors, eigenvalues);
   
 #ifdef DEBUG
         for( Dimension i_dim = 1; i_dim < 3; ++i_dim )
             ASSERT ( std::abs(eigenvalues[i_dim - 1]) <= std::abs(eigenvalues[i_dim]) );
 #endif
       
         return ((eigenvalues[0] + eigenvalues[1])/(eigenvalues[2]));
       }

References DGtal::EigenDecomposition< TN, TComponent, TMatrix >::getEigenDecomposition(), DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myAccum, and DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myArea.

◆ pushSurfel()

template<typename TSurfel , typename TEmbedder >

void DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::pushSurfel	(	const Surfel &	aSurf,
		const double	aDistance
	)

inline

Add the geometrical embedding of a surfel to the point list and update the tensor voting.

Parameters

aSurf	a surfel to add
aDistance	distance of aSurf to the neighborhood boundary

Definition at line 113 of file TensorVotingFeatureExtraction.h.

       {
         if (myFirstSurfel)
           {
             myReceiver =  myEmbedder->operator()(aSurf);
             myFirstSurfel = false;
           }
         else
           {
             myArea+= aDistance;
             const RealPoint p = myEmbedder->operator()(aSurf);
             const RealPoint v = p - myReceiver;
           
             double maxcol = 0.0;
             double matnorm = 0.0;
           
             // I - vv^t/||vv^t||
             for(DGtal::Dimension i= 0; i <3; i++)
               {
                 maxcol = 0.0;
                 for(DGtal::Dimension j=0; j < 3; j++)
                   {
                     myVote.setComponent(i,j, v(i)*v(j));
                     if (std::abs(v(i)*v(j)) > maxcol)
                       maxcol = std::abs(v(i)*v(j));
                   }
                 matnorm += maxcol;
               }
         
             myAccum += (myId - myVote/matnorm)*aDistance;
           }
       }

References DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myAccum, DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myArea, DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myEmbedder, DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myFirstSurfel, DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myId, DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myReceiver, DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myVote, and DGtal::SimpleMatrix< TComponent, TM, TN >::setComponent().

◆ reset()

template<typename TSurfel , typename TEmbedder >

void DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::reset ( )

inline

Reset the point list.

Definition at line 174 of file TensorVotingFeatureExtraction.h.

       {
         myArea = 0.0;
         myFirstSurfel = true;
         myAccum.constant(0.0);
       }

References DGtal::SimpleMatrix< TComponent, TM, TN >::constant(), DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myAccum, DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myArea, and DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myFirstSurfel.

Field Documentation

◆ myAccum

template<typename TSurfel , typename TEmbedder >

SimpleMatrix<double, 3, 3> DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myAccum

private

Covariance accumulator.

Definition at line 197 of file TensorVotingFeatureExtraction.h.

Referenced by DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::eval(), DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::pushSurfel(), DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::reset(), and DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::TensorVotingFeatureExtraction().

◆ myArea

template<typename TSurfel , typename TEmbedder >

double DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myArea

private

Convolution kernel area.

Definition at line 200 of file TensorVotingFeatureExtraction.h.

◆ myEmbedder

template<typename TSurfel , typename TEmbedder >

const SCellEmbedder* DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myEmbedder

private

Alias of the geometrical embedder.

Definition at line 188 of file TensorVotingFeatureExtraction.h.

Referenced by DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::pushSurfel().

◆ myFirstSurfel

template<typename TSurfel , typename TEmbedder >

bool DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myFirstSurfel

private

First surfel flag.

Definition at line 185 of file TensorVotingFeatureExtraction.h.

Referenced by DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::pushSurfel(), DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::reset(), and DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::TensorVotingFeatureExtraction().

◆ myH

template<typename TSurfel , typename TEmbedder >

double DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myH

private

Definition at line 191 of file TensorVotingFeatureExtraction.h.

◆ myId

template<typename TSurfel , typename TEmbedder >

SimpleMatrix<double, 3, 3> DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myId

private

Definition at line 197 of file TensorVotingFeatureExtraction.h.

Referenced by DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::pushSurfel(), and DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::TensorVotingFeatureExtraction().

◆ myReceiver

template<typename TSurfel , typename TEmbedder >

RealPoint DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myReceiver

private

Receiver (embedding of the starting surfel)

Definition at line 194 of file TensorVotingFeatureExtraction.h.

Referenced by DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::pushSurfel().

◆ myVote

template<typename TSurfel , typename TEmbedder >

SimpleMatrix<double, 3, 3> DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::myVote

private

Definition at line 197 of file TensorVotingFeatureExtraction.h.

Referenced by DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >::pushSurfel().

The documentation for this class was generated from the following file:

TensorVotingFeatureExtraction.h

Public Types

Public Member Functions

Private Attributes

Detailed Description

template<typename TSurfel, typename TEmbedder> class DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >

Member Typedef Documentation

◆ Quantity

◆ RealPoint

◆ SCellEmbedder

◆ Surfel

Constructor & Destructor Documentation

◆ TensorVotingFeatureExtraction()

Member Function Documentation

◆ eval()

◆ pushSurfel()

◆ reset()

Field Documentation

◆ myAccum

◆ myArea

◆ myEmbedder

◆ myFirstSurfel

◆ myH

◆ myId

◆ myReceiver

◆ myVote

template<typename TSurfel, typename TEmbedder>
class DGtal::functors::TensorVotingFeatureExtraction< TSurfel, TEmbedder >