#include <vpFeatureMoment.h>

Inheritance diagram for vpFeatureMoment:

Public Types
enum	vpBasicFeatureDeallocatorType { user, vpServo }

Public Member Functions
	vpFeatureMoment (vpMomentDatabase &data_base, double A_=0.0, double B_=0.0, double C_=0.0, vpFeatureMomentDatabase *featureMoments=NULL, unsigned int nbmatrices=1)

virtual	~vpFeatureMoment ()

virtual void	compute_interaction (void)

vpBasicFeature *	duplicate () const

void	display (const vpCameraParameters &cam, const vpImage< unsigned char > &I, const vpColor &color=vpColor::green, unsigned int thickness=1) const

void	display (const vpCameraParameters &cam, const vpImage< vpRGBa > &I, const vpColor &color=vpColor::green, unsigned int thickness=1) const

int	getDimension (unsigned int select=FEATURE_ALL) const

void	init (void)

vpMatrix	interaction (const unsigned int select=FEATURE_ALL)

void	linkTo (vpFeatureMomentDatabase &featureMoments)

virtual const char *	momentName () const =0

virtual const char *	name () const =0

void	print (const unsigned int select=FEATURE_ALL) const

void	update (double A, double B, double C)

unsigned int	dimension_s ()

virtual double	operator[] (const unsigned int i) const

vpColVector	get_s (unsigned int select=FEATURE_ALL) const

virtual vpColVector	error (const vpBasicFeature &s_star, const unsigned int select=FEATURE_ALL)

void	setFlags ()

void	setDeallocate (vpBasicFeatureDeallocatorType d)

vpBasicFeatureDeallocatorType	getDeallocate ()

Static Public Member Functions
static unsigned int	selectAll ()

Static Public Attributes
static const unsigned int	FEATURE_LINE [32]

static const unsigned int	FEATURE_ALL = 0xffff

Protected Member Functions
const vpMoment &	getMoment () const

void	resetFlags ()

Protected Attributes
const vpMoment *	moment

vpMomentDatabase &	moments

vpFeatureMomentDatabase *	featureMomentsDataBase

std::vector< vpMatrix >	interaction_matrices

double	A

double	B

double	C

char	_name [255]

vpColVector	s

unsigned int	dim_s

bool *	flags

unsigned int	nbParameters

vpBasicFeatureDeallocatorType	deallocate

Detailed Description

This class defines shared system methods/attributes for 2D moment features but no functional code. It is used to compute interaction matrices for moment features.

While vpMoment-type classes do only compute moment values and can by used for almost anything, vpFeatureMoment-type classes are specifically designed for visual servoing. More importantly, a vpFeatureMoment is used to compute the interaction matrix associated to it's moment primitive.

This class is virtual and cannot be used directly. It defines the following characteristics common to all moment features:

Plane orientation parameters (A,B,C): Each camera frame corresponds to a physical planar object contained in a plane. This plane's equation has the following form: $A \times x+B \times y + C = \frac{1}{Z}$ . These parameters can be updated anytime.
Get corresponding moment primitive: for example a vpFeatureMomentCInvariant will provide access to a vpMomentCInvariant instance.
Provide access to a feature database (vpFeatureMomentDatabase).
All interaction matrices (different from vpBasicFeature::interaction which selects the required interaction matrix).

Like vpMoment, vpFeatureMoment provides a vpFeatureMoment::update() method. But unlike vpMoment::update() which only acknowledges the new object, the vpFeatureMoment::update() acknowledges the new plane parameters AND computes the interaction matrices associated with the feature.

A vpFeatureMoment will be often part of a vpFeatureMomentDatabase in the same way a vpMoment is part of a vpMomentDatabase. This database is specified inside the vpFeatureMoment::vpFeatureMoment() constructor. As a result, a vpFeatureMoment will be able to access other vpFeatureMoments through this database.

A vpBasicFeature can be duplicated into a vpMomentGenericFeature. In that case, all data in the vpBasicFeature is copied but the feature's name is lost. For example if a vpFeatureMomentCInvariant is duplicated, the duplicata will be operational but could not be used in a vpFeatureMomentDatabase.

Note that you can use vpFeatureMoment to do visual servoing but it is not it's only purpose. You may compute your interaction matrices with vpFeatureMoment::update() and use them for any purpose.

Attention: - A vpFeatureMoment is not responsible for updating the moment primitives it depends on. Make sure your vpMoments are all up to date before computing an interaction matrix using vpFeatureMoment.; - Be careful with orders. Often, computing a feature of order n requires vpMoment primitives of order n+1. Make sure to check the documentation of the specialised vpFeatureMoment classes when deciding to which order you want to initialize the object. An object of order 6 should be sufficient for all classic implementations of vpFeatureMoment.

Here is an example of how to use a vpFeatureMoment (in this case vpFeatureMomentBasic).

#include <visp/vpPoint.h>
#include <visp/vpMomentObject.h>
#include <visp/vpMomentBasic.h>
#include <visp/vpMomentDatabase.h>
#include <visp/vpFeatureMoment.h>
#include <visp/vpFeatureMomentBasic.h>
int main()
{
vpPoint p;
std::vector<vpPoint> vec_p; // vector that contains the vertices
p.set_x(1); p.set_y(1); // coordinates in meters in the image plane (vertex 1)
vec_p.push_back(p);
p.set_x(2); p.set_y(2); // coordinates in meters in the image plane (vertex 2)
vec_p.push_back(p);
vpMomentObject obj(3); // Init object of order 3 because we need
// vpFeatureMomentBasic of order 2 which
// implies third-order moment primitives
obj.setType(vpMomentObject::DISCRETE); // Discrete mode for object
obj.fromVector(vec_p); 
vpMomentDatabase mdb; //database for moment primitives. This will
//only contain the basic moment.
vpMomentBasic bm; //basic moment (this particular moment is nothing
//more than a shortcut to the vpMomentObject)  
bm.linkTo(mdb); //add basic moment to moment database
vpFeatureMomentBasic fmb(mdb,0,0,1,NULL);
//update and compute the vpMoment BEFORE doing any operations with
//vpFeatureMoment
bm.update(obj);
bm.compute();
fmb.update(0,0,1); //update the vpFeatureMoment with a plane
//configuration
std::cout << fmb.interaction(1,1) << std::endl;
return 0;
}

Definition at line 146 of file vpFeatureMoment.h.

Member Enumeration Documentation

enum vpBasicFeature::vpBasicFeatureDeallocatorType

inherited

Indicates who should deallocate the feature.

Enumerator
user
vpServo

Definition at line 154 of file vpBasicFeature.h.

Constructor & Destructor Documentation

vpFeatureMoment::vpFeatureMoment	(	vpMomentDatabase &	data_base,
		double	A_ = `0.0`,
		double	B_ = `0.0`,
		double	C_ = `0.0`,
		vpFeatureMomentDatabase *	featureMoments = `NULL`,
		unsigned int	nbmatrices = `1`
	)

inline

Initializes the feature with information about the database of moment primitives, the object plane, feature database and matrix size.

Parameters

data_base	: Moment database. The database of moment primitives (first parameter) is mandatory. It is used to access different moment values later used to compute the final matrix.
A_	: Plane coefficient in a $A \times x+B \times y + C = \frac{1}{Z}$ plane.
B_	: Plane coefficient in a $A \times x+B \times y + C = \frac{1}{Z}$ plane.
C_	: Plane coefficient in a $A \times x+B \times y + C = \frac{1}{Z}$ plane.
featureMoments	: Feature database
nbmatrices	: If you want to create a new vpFeatureMoment implementation, your feature will often have a matrix size of n lines. You can specify the number of lines by this parameter.

Definition at line 169 of file vpFeatureMoment.h.

vpFeatureMoment::~vpFeatureMoment ( )

virtual

Definition at line 253 of file vpFeatureMoment.cpp.

References vpBasicFeature::flags.

Member Function Documentation

void vpFeatureMoment::compute_interaction ( void )

virtual

Reimplemented in vpFeatureMomentGravityCenterNormalized, vpFeatureMomentGravityCenter, vpFeatureMomentCInvariant, vpFeatureMomentAreaNormalized, vpFeatureMomentAlpha, vpFeatureMomentCentered, vpFeatureMomentBasic, and vpFeatureMomentArea.

Definition at line 249 of file vpFeatureMoment.cpp.

Referenced by update().

unsigned int vpBasicFeature::dimension_s ( )

inlineinherited

Return the dimension of the feature vector $\bf s$ .

Definition at line 102 of file vpBasicFeature.h.

void vpFeatureMoment::display	(	const vpCameraParameters &	cam,
		const vpImage< unsigned char > &	I,
		const vpColor &	color = `vpColor::green`,
		unsigned int	thickness = `1`
	)		const

virtual

Not implemented since visual representation of a moment doesn't often make sense.

Implements vpBasicFeature.

Definition at line 115 of file vpFeatureMoment.cpp.

void vpFeatureMoment::display	(	const vpCameraParameters &	cam,
		const vpImage< vpRGBa > &	I,
		const vpColor &	color = `vpColor::green`,
		unsigned int	thickness = `1`
	)		const

virtual

Not implemented since visual representation of a moment doesn't often make sense.

Implements vpBasicFeature.

Definition at line 128 of file vpFeatureMoment.cpp.

vpBasicFeature * vpFeatureMoment::duplicate ( ) const

virtual

Duplicates the feature into a vpGenericFeature harbouring the same properties. The resulting feature is of vpMomentGenericFeature type. While it still can compute interaction matrices and has acces to it's moment primitive, it has lost all precise information about its precise type and therefore cannot be used in a feature database.

Returns: The corresponding feature.

Implements vpBasicFeature.

Definition at line 213 of file vpFeatureMoment.cpp.

References A, B, C, vpBasicFeature::dim_s, featureMomentsDataBase, vpBasicFeature::flags, interaction_matrices, moment, moments, vpBasicFeature::nbParameters, vpColVector::resize(), and vpBasicFeature::s.

vpColVector vpBasicFeature::error	(	const vpBasicFeature &	s_star,
		const unsigned int	select = `FEATURE_ALL`
	)

virtualinherited

Compute the error between two visual features from a subset of the possible features.

Reimplemented in vpFeatureTranslation, vpFeatureThetaU, vpFeaturePointPolar, vpFeaturePoint3D, vpFeatureLine, vpFeaturePoint, vpFeatureDepth, vpGenericFeature, vpFeatureMomentAlpha, vpFeatureLuminance, vpFeatureVanishingPoint, vpFeatureEllipse, and vpFeatureSegment.

Examples:: manServoMomentsSimple.cpp.

Definition at line 161 of file vpBasicFeature.cpp.

References vpBasicFeature::dim_s, vpBasicFeature::FEATURE_LINE, vpBasicFeature::get_s(), and vpBasicFeature::s.

Referenced by vpServo::computeError().

vpColVector vpBasicFeature::get_s ( unsigned int select = FEATURE_ALL ) const

inherited

Get the feature vector $\bf s$ .

Examples:: servoAfma6Ellipse2DCamVelocity.cpp.

Definition at line 123 of file vpBasicFeature.cpp.

References vpBasicFeature::dim_s, vpBasicFeature::FEATURE_LINE, vpBasicFeature::s, and vpMatrix::stackMatrices().

Referenced by vpServo::computeError(), vpBasicFeature::error(), vpGenericFeature::error(), vpFeatureDepth::error(), vpFeatureThetaU::error(), and vpFeatureTranslation::error().

vpBasicFeatureDeallocatorType vpBasicFeature::getDeallocate ( )

inlineinherited

Definition at line 164 of file vpBasicFeature.h.

int vpFeatureMoment::getDimension ( unsigned int select = FEATURE_ALL ) const

Feature's dimension according to selection.

Definition at line 88 of file vpFeatureMoment.cpp.

References vpBasicFeature::dim_s, and vpBasicFeature::FEATURE_LINE.

const vpMoment& vpFeatureMoment::getMoment ( ) const

inlineprotected

Definition at line 149 of file vpFeatureMoment.h.

void vpFeatureMoment::init ( void )

virtual

Initialize common parameters for moment features.

Implements vpBasicFeature.

Definition at line 60 of file vpFeatureMoment.cpp.

References vpBasicFeature::dim_s, vpBasicFeature::flags, vpMoment::get(), moment, vpBasicFeature::nbParameters, vpColVector::resize(), and vpBasicFeature::s.

vpMatrix vpFeatureMoment::interaction ( const unsigned int select = FEATURE_ALL )

virtual

Retrieves the interaction matrix. No computation is done.

Parameters

select : Feature selector.

Returns: The corresponding interaction matrix.

There is no rule about the format of the feature selector. It may be different for different features. For example, for vpFeatureMomentBasic or vpFeatureMomentCentered features, select may refer to the $ (i,j) $ couple in the $j \times order + i$ format, but for vpFeatureMomentCInvariant the selector allows to select couples $ (i,j,k,l...) $ in the following format: 1 << i

1 << j + 1 << k + 1 << l.

Implements vpBasicFeature.

Definition at line 193 of file vpFeatureMoment.cpp.

References vpBasicFeature::dim_s, vpBasicFeature::FEATURE_LINE, interaction_matrices, and vpMatrix::stackMatrices().

void vpFeatureMoment::linkTo ( vpFeatureMomentDatabase & featureMoments )

Links the feature to the feature's database. NB: The feature's database is different from the moment's database.

Parameters

featureMoments : database in which the moment features are stored.

Definition at line 236 of file vpFeatureMoment.cpp.

References _name, featureMomentsDataBase, vpException::memoryAllocationError, and name().

Referenced by vpFeatureMomentCommon::vpFeatureMomentCommon().

virtual const char* vpFeatureMoment::momentName ( ) const

pure virtual

Name of the moment corresponding to the feature. This allows to locate the moment associated with the feature in the provided database.

Implemented in vpFeatureMomentGravityCenterNormalized, vpMomentGenericFeature, vpFeatureMomentGravityCenter, vpFeatureMomentCInvariant, vpFeatureMomentAreaNormalized, vpFeatureMomentAlpha, vpFeatureMomentCentered, vpFeatureMomentBasic, and vpFeatureMomentArea.

Referenced by update().

virtual const char* vpFeatureMoment::name ( ) const

pure virtual

Name of the feature used to locate it in the database of features.

Implemented in vpFeatureMomentGravityCenterNormalized, vpMomentGenericFeature, vpFeatureMomentGravityCenter, vpFeatureMomentCInvariant, vpFeatureMomentAreaNormalized, vpFeatureMomentAlpha, vpFeatureMomentCentered, vpFeatureMomentBasic, and vpFeatureMomentArea.

Referenced by linkTo().

virtual double vpBasicFeature::operator[] ( const unsigned int i ) const

inlinevirtualinherited

Return element i in the state vector (usage : x = s[i] )

Definition at line 113 of file vpBasicFeature.h.

void vpFeatureMoment::print ( const unsigned int select = FEATURE_ALL ) const

virtual

Outputs the content of the feature: it's corresponding selected moments.

Implements vpBasicFeature.

Definition at line 102 of file vpFeatureMoment.cpp.

References vpBasicFeature::dim_s, vpBasicFeature::FEATURE_LINE, and vpBasicFeature::s.

void vpBasicFeature::resetFlags ( )

protectedinherited

Definition at line 141 of file vpBasicFeature.cpp.

References vpBasicFeature::flags, and vpBasicFeature::nbParameters.

Referenced by vpFeatureEllipse::interaction(), vpFeatureVanishingPoint::interaction(), vpFeatureDepth::interaction(), vpFeaturePoint::interaction(), vpFeatureLine::interaction(), vpFeaturePoint3D::interaction(), vpFeaturePointPolar::interaction(), vpFeatureThetaU::interaction(), and vpFeatureTranslation::interaction().

static unsigned int vpBasicFeature::selectAll ( )

inlinestaticinherited

Select all the features.

Definition at line 116 of file vpBasicFeature.h.

void vpBasicFeature::setDeallocate ( vpBasicFeatureDeallocatorType d )

inlineinherited

Definition at line 163 of file vpBasicFeature.h.

Referenced by vpServo::addFeature().

void vpBasicFeature::setFlags ( )

inherited

Set feature flags to true to prevent warning when re-computing the interaction matrix without having updated the feature.

Definition at line 151 of file vpBasicFeature.cpp.

References vpBasicFeature::flags, and vpBasicFeature::nbParameters.

void vpFeatureMoment::update	(	double	A_,
		double	B_,
		double	C_
	)

Updates the interaction matrices with the image plane the camera is facing. The plane must be in the format: $\frac{1}{Z}=Ax+By+C$ . The moment primitives MUST be updated before calling this function.

This method also computes the interaction matrix. Therefore, you must call vpFeatureMoment::update before calling vpFeatureMoment::interaction.

Attention: The behaviour of this method is not the same as vpMoment::update which only acknowledges the new object. This method also computes the interaction matrices.

Parameters

A_	: A coefficient of the plane.
B_	: B coefficient of the plane.
C_	: C coefficient of the plane.

Definition at line 149 of file vpFeatureMoment.cpp.

References A, B, C, compute_interaction(), vpBasicFeature::dim_s, vpBasicFeature::flags, vpMoment::get(), vpMomentDatabase::get(), moment, momentName(), moments, vpBasicFeature::nbParameters, vpException::notInitialized, vpColVector::resize(), and vpBasicFeature::s.

Referenced by vpFeatureMomentCommon::updateAll().

Member Data Documentation

char vpFeatureMoment::_name[255]

protected

Definition at line 157 of file vpFeatureMoment.h.

Referenced by linkTo().

double vpFeatureMoment::A

protected

Definition at line 154 of file vpFeatureMoment.h.

Referenced by vpFeatureMomentArea::compute_interaction(), vpFeatureMomentBasic::compute_interaction(), vpFeatureMomentCentered::compute_interaction(), vpFeatureMomentAlpha::compute_interaction(), vpFeatureMomentAreaNormalized::compute_interaction(), vpFeatureMomentGravityCenter::compute_interaction(), vpFeatureMomentGravityCenterNormalized::compute_interaction(), duplicate(), and update().

double vpFeatureMoment::B

protected

Definition at line 155 of file vpFeatureMoment.h.

Referenced by vpFeatureMomentArea::compute_interaction(), vpFeatureMomentBasic::compute_interaction(), vpFeatureMomentCentered::compute_interaction(), vpFeatureMomentAlpha::compute_interaction(), vpFeatureMomentAreaNormalized::compute_interaction(), vpFeatureMomentGravityCenter::compute_interaction(), vpFeatureMomentGravityCenterNormalized::compute_interaction(), duplicate(), and update().

double vpFeatureMoment::C

protected

Definition at line 156 of file vpFeatureMoment.h.

Referenced by vpFeatureMomentArea::compute_interaction(), vpFeatureMomentBasic::compute_interaction(), vpFeatureMomentCentered::compute_interaction(), vpFeatureMomentAreaNormalized::compute_interaction(), vpFeatureMomentGravityCenter::compute_interaction(), vpFeatureMomentGravityCenterNormalized::compute_interaction(), duplicate(), and update().

vpBasicFeatureDeallocatorType vpBasicFeature::deallocate

protectedinherited

Definition at line 161 of file vpBasicFeature.h.

Referenced by vpFeatureEllipse::interaction(), vpFeatureVanishingPoint::interaction(), vpFeatureSegment::interaction(), vpFeatureDepth::interaction(), vpFeaturePoint::interaction(), vpFeatureLine::interaction(), vpFeaturePoint3D::interaction(), vpFeaturePointPolar::interaction(), vpFeatureThetaU::interaction(), vpFeatureTranslation::interaction(), and vpBasicFeature::operator=().

unsigned int vpBasicFeature::dim_s

protectedinherited

Dimension of the visual feature.

Definition at line 93 of file vpBasicFeature.h.

const unsigned int vpBasicFeature::FEATURE_ALL = 0xffff

staticinherited

Definition at line 87 of file vpBasicFeature.h.

Referenced by vpFeatureDepth::error(), vpFeatureDepth::interaction(), and vpFeatureDepth::print().

const unsigned int vpBasicFeature::FEATURE_LINE

staticinherited

Initial value:

=
    {
    (unsigned int)(1 <<  0),    (unsigned int)(1 <<  1),
    (unsigned int)(1 <<  2),    (unsigned int)(1 <<  3),
    (unsigned int)(1 <<  4),    (unsigned int)(1 <<  5),
    (unsigned int)(1 <<  6),    (unsigned int)(1 <<  7),
    (unsigned int)(1 <<  8),    (unsigned int)(1 <<  9),
    (unsigned int)(1 << 10),    (unsigned int)(1 << 11),
    (unsigned int)(1 << 12),    (unsigned int)(1 << 13),
    (unsigned int)(1 << 14),    (unsigned int)(1 << 15),
    (unsigned int)(1 << 16),    (unsigned int)(1 << 17),
    (unsigned int)(1 << 18),    (unsigned int)(1 << 19),
    (unsigned int)(1 << 20),    (unsigned int)(1 << 21),
    (unsigned int)(1 << 22),    (unsigned int)(1 << 23),
    (unsigned int)(1 << 24),    (unsigned int)(1 << 25),
    (unsigned int)(1 << 26),    (unsigned int)(1 << 27),
    (unsigned int)(1 << 28),    (unsigned int)(1 << 29),
    (unsigned int)(1 << 30),    (unsigned int)(1 << 31)
    }

Definition at line 85 of file vpBasicFeature.h.

Referenced by vpBasicFeature::error(), vpGenericFeature::error(), vpBasicFeature::get_s(), vpBasicFeature::getDimension(), getDimension(), vpGenericFeature::interaction(), interaction(), vpGenericFeature::print(), and print().

vpFeatureMomentDatabase* vpFeatureMoment::featureMomentsDataBase

protected

Definition at line 151 of file vpFeatureMoment.h.

Referenced by vpFeatureMomentCInvariant::compute_interaction(), duplicate(), and linkTo().

bool* vpBasicFeature::flags

protectedinherited

Ensure that all the parameters needed to compute the iteraction matrix are set.

Definition at line 96 of file vpBasicFeature.h.

std::vector<vpMatrix> vpFeatureMoment::interaction_matrices

protected

Definition at line 152 of file vpFeatureMoment.h.

const vpMoment* vpFeatureMoment::moment

protected

Definition at line 148 of file vpFeatureMoment.h.

vpMomentDatabase& vpFeatureMoment::moments

protected

Definition at line 150 of file vpFeatureMoment.h.

Referenced by vpFeatureMomentArea::compute_interaction(), vpFeatureMomentCentered::compute_interaction(), vpFeatureMomentAlpha::compute_interaction(), vpFeatureMomentAreaNormalized::compute_interaction(), vpFeatureMomentCInvariant::compute_interaction(), vpFeatureMomentGravityCenter::compute_interaction(), vpFeatureMomentGravityCenterNormalized::compute_interaction(), duplicate(), and update().

unsigned int vpBasicFeature::nbParameters

protectedinherited

Number of parameters needed to compute the interaction matrix.

Definition at line 98 of file vpBasicFeature.h.

vpColVector vpBasicFeature::s

protectedinherited

State of the visual feature.

Definition at line 91 of file vpBasicFeature.h.

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation