vpMomentAreaNormalized Class Reference

#include <vpMomentAreaNormalized.h>

Inheritance diagram for vpMomentAreaNormalized:

Public Member Functions
	vpMomentAreaNormalized (double a_star, double Z_star)
void	compute () VP_OVERRIDE
double	getDesiredArea () const
double	getDesiredDepth () const
void	setDesiredDepth (double Z_star)
void	setDesiredArea (double a_star)
Inherited functionalities from vpMoment
const vpMomentObject &	getObject () const
const std::vector< double > &	get () const
void	linkTo (vpMomentDatabase &moments)
void	update (vpMomentObject &object)

Protected Member Functions
vpMomentDatabase &	getMoments () const

Protected Attributes
std::vector< double >	values

Deprecated functions
VP_DEPRECATED double	getDesiredSurface () const
const std::string	name () const VP_OVERRIDE
void	printDependencies (std::ostream &os) const VP_OVERRIDE
VISP_EXPORT std::ostream &	operator<< (std::ostream &os, const vpMomentAreaNormalized &v)

Detailed Description

Class handling the normalized surface moment that is invariant in scale and used to estimate depth.

This moment depends on vpMomentCentered.

The idea behind vpMomentAreaNormalized is described in [54].

During a visual servoing process, a vpMomentAreaNormalized will converge towards the desired depth when the current surface will converge to the destination surface. It is defined as follows: where a is the current surface and a* the destination surface. Consequently, the vpMomentAreaNormalized needs to have information about the desired depth Z* and the desired surface a*.

Warning

About the order of the object. The surface (referred to as a in the above paragraph) depends of the nature of the object.

• In case of a continuous object (when vpMomentObject::getType() is vpMomentObject::DENSE_FULL_OBJECT or vpMomentObject::DENSE_POLYGON) .
• In case of a discrete object (when vpMomentObject::getType() is vpMomentObject::DISCRETE) .

Therefore, a vpMomentObject has to be of minimum order 2 in order to compute a vpMomentAreaNormalized moment in the discrete case and of minimum order 0 in continuous cases.

This example shows a computation in the discrete case.

#include <visp3/core/vpMomentAreaNormalized.h>
#include <visp3/core/vpMomentCentered.h>
#include <visp3/core/vpMomentDatabase.h>
#include <visp3/core/vpMomentGravityCenter.h>
#include <visp3/core/vpMomentObject.h>
#include <visp3/core/vpPoint.h>
 
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
 
int main()
{
  vpPoint p;
  std::vector<vpPoint> vec_p; // vector that contains object points
 
  p.set_x(1); p.set_y(1); // coordinates in meters in the image plane of point 1
  vec_p.push_back(p);
  p.set_x(2); p.set_y(2); // coordinates in meters in the image plane of point 2
  vec_p.push_back(p);

  vpMomentObject obj(2); // Object where all the moment defined with
                        // i+j <= 2 will be computed below. Order is
                        // 2 because in discrete mode, the surface
                        // computation is a=mu02+mu02
 
  obj.setType(vpMomentObject::DISCRETE); // Discrete mode for object
  obj.fromVector(vec_p); // initialize the object with the points coordinates
 
  vpMomentDatabase db; //reference database
  vpMomentGravityCenter g; // declaration of gravity center
  vpMomentCentered mc; //  centered moments
 vpMomentAreaNormalized an(2,1); //declare normalized surface with
                                //destination depth of 1 meter and
                                //destination surface of 2 m2
 
  g.linkTo(db); //add gravity center to database
  mc.linkTo(db); //add centered moments
  an.linkTo(db); //add alpha depending on centered moments
 
  db.updateAll(obj); // All of the moments must be updated, not just an
 
  g.compute(); // compute the moment
  mc.compute(); //compute centered moments AFTER gravity center
  an.compute(); //compute alpha AFTER centered moments.
 
  std::cout << an << std::endl;
 
  return 0;
}

This code produces the following output:

An:1.41421

Examples

mbot-apriltag-ibvs.cpp, servoBebop2.cpp, and servoPixhawkDroneIBVS.cpp.

Definition at line 138 of file vpMomentAreaNormalized.h.

Constructor & Destructor Documentation

vpMomentAreaNormalized()

vpMomentAreaNormalized::vpMomentAreaNormalized	(	double	a_star,
		double	Z_star )

Default constructor.

Parameters

a_star	: desired area a* when the visual servoing converges.
Z_star	: desired depth Z* when the visual servoing converges.

Definition at line 79 of file vpMomentAreaNormalized.cpp.

References vpMoment::values, and vpMoment::vpMoment().

Referenced by operator<<.

Member Function Documentation

compute()

BEGIN_VISP_NAMESPACE void vpMomentAreaNormalized::compute ( )

virtual

Computes the normalized area . Depends on vpMomentCentered.

Implements vpMoment.

Definition at line 48 of file vpMomentAreaNormalized.cpp.

References vpMomentObject::DISCRETE, vpMomentCentered::get(), vpMomentDatabase::get(), vpMomentObject::get(), vpMoment::getMoments(), vpMoment::getObject(), vpException::notInitialized, and vpMoment::values.

get()

const std::vector< double > & vpMoment::get ( ) const

inlineinherited

Returns all values computed by the moment.

Returns

vector of values

Definition at line 155 of file vpMoment.h.

References values.

Referenced by vpMomentGravityCenterNormalized::compute(), vpFeatureMomentArea::compute_interaction(), vpFeatureMomentAreaNormalized::compute_interaction(), vpFeatureMomentGravityCenterNormalized::compute_interaction(), vpMomentCentered::get(), and vpMomentGravityCenterNormalized::printDependencies().

getDesiredArea()

double vpMomentAreaNormalized::getDesiredArea ( ) const

inline

Retrieves the desired surface a* as specified in the constructor.

Definition at line 151 of file vpMomentAreaNormalized.h.

getDesiredDepth()

double vpMomentAreaNormalized::getDesiredDepth ( ) const

inline

Retrieves the desired depth Z* as specified in the constructor.

Definition at line 156 of file vpMomentAreaNormalized.h.

getDesiredSurface()

VP_DEPRECATED double vpMomentAreaNormalized::getDesiredSurface ( ) const

inline

Deprecated

Use rather getDesiredArea() Retrieves the desired surface a* as specified in the constructor.

Definition at line 179 of file vpMomentAreaNormalized.h.

getMoments()

vpMomentDatabase & vpMoment::getMoments ( ) const

inlineprotectedinherited

Returns the linked moment database.

Returns

the moment database

Definition at line 118 of file vpMoment.h.

Referenced by vpMomentAlpha::compute(), vpMomentArea::compute(), vpMomentAreaNormalized::compute(), vpMomentCentered::compute(), vpMomentCInvariant::compute(), vpMomentGravityCenterNormalized::compute(), vpMomentAlpha::printDependencies(), vpMomentArea::printDependencies(), vpMomentAreaNormalized::printDependencies(), vpMomentCentered::printDependencies(), and vpMomentGravityCenterNormalized::printDependencies().

getObject()

const vpMomentObject & vpMoment::getObject ( ) const

inlineinherited

Definition at line 150 of file vpMoment.h.

Referenced by vpMomentArea::compute(), vpMomentAreaNormalized::compute(), vpMomentCentered::compute(), vpMomentCInvariant::compute(), vpMomentGravityCenter::compute(), vpMomentBasic::get(), vpMomentBasic::get(), vpMomentCentered::get(), vpMomentBasic::operator<<, vpMomentCentered::operator<<, vpMomentArea::printDependencies(), vpMomentAreaNormalized::printDependencies(), vpMomentBasic::printDependencies(), vpMomentCentered::printDependencies(), vpMomentGravityCenter::printDependencies(), vpMomentCentered::printWithIndices(), and vpMomentCentered::set().

linkTo()

void vpMoment::linkTo ( vpMomentDatabase & data_base )

inherited

Links the moment to a database of moment primitives. If the moment depends on other moments, these moments must be linked to the same database.

Attention

Two moments of the same class cannot be stored in the same database

#include <visp3/core/vpMomentCentered.h>
#include <visp3/core/vpMomentDatabase.h>
#include <visp3/core/vpMomentGravityCenter.h>
#include <visp3/core/vpMomentObject.h>
#include <visp3/core/vpPoint.h>
 
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
 
int main()
{
  vpPoint p;
  std::vector<vpPoint> vec_p;
 
  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(2);
  obj.setType(vpMomentObject::DISCRETE); // Discrete mode.
  obj.fromVector(vec_p); // Init the dense object with the polygon
 
  vpMomentDatabase db;
  vpMomentGravityCenter G; // declaration of gravity center
  vpMomentCentered mc;     // mc contains centered moments
 
  G.linkTo(db);  // add gravity center to database
  mc.linkTo(db); // centered moments depend on gravity, add them to the
                 // database to grant access
 
  G.update(obj);  // specify the object for gravity center
  mc.update(obj); // and for centered moments
 
  G.compute();  // compute the moment
  mc.compute(); // compute centered moments AFTER gravity center
 
  return 0;
}

Parameters

data_base

: database of moment primitives.

Examples

mbot-apriltag-ibvs.cpp, servoBebop2.cpp, servoPixhawkDroneIBVS.cpp, and testMomentAlpha.cpp.

Definition at line 114 of file vpMoment.cpp.

References name().

Referenced by vpMomentCommon::getAlpha(), vpMomentCommon::getMu3(), and vpMomentCommon::getSurface().

name()

const std::string vpMomentAreaNormalized::name ( ) const

inlinevirtual

Moment name.

Implements vpMoment.

Definition at line 186 of file vpMomentAreaNormalized.h.

printDependencies()

void vpMomentAreaNormalized::printDependencies ( std::ostream & os ) const

virtual

Prints dependencies namely,

1. Depth at desired pose Z*
2. Area moment at desired pose m00* if DENSE moment object, (mu20* + mu02*) if DISCRETE moment object
3. Area moment at current pose m00 if DENSE moment object, (mu20 + mu02) if DISCRETE moment object

Reimplemented from vpMoment.

Definition at line 93 of file vpMomentAreaNormalized.cpp.

References vpMomentObject::DISCRETE, vpMomentCentered::get(), vpMomentDatabase::get(), vpMomentObject::get(), vpMoment::getMoments(), vpMoment::getObject(), and vpException::notInitialized.

setDesiredArea()

void vpMomentAreaNormalized::setDesiredArea ( double a_star )

inline

Set the desired area a* to a new value than the one specified in the constructor. This value has to be set before calling compute().

Definition at line 168 of file vpMomentAreaNormalized.h.

setDesiredDepth()

void vpMomentAreaNormalized::setDesiredDepth ( double Z_star )

inline

Set the desired depth Z* to a new value than the one specified in the constructor. This value has to be set before calling compute().

Definition at line 162 of file vpMomentAreaNormalized.h.

update()

void vpMoment::update ( vpMomentObject & moment_object )

inherited

Updates the moment with the current object. This does not compute any values.

Parameters

moment_object

: object descriptor of the current camera vision.

Definition at line 127 of file vpMoment.cpp.

Referenced by name().

Friends And Related Symbol Documentation

operator<<

VISP_EXPORT std::ostream & operator<< ( std::ostream & os, const vpMomentAreaNormalized & v )

friend

Outputs the moment's values to a stream.

Definition at line 116 of file vpMomentAreaNormalized.cpp.

References operator<<, vpMoment::values, and vpMomentAreaNormalized().

Referenced by operator<<.

Member Data Documentation

values

std::vector<double> vpMoment::values

protectedinherited

Definition at line 113 of file vpMoment.h.

Referenced by vpMomentCInvariant::C1(), vpMomentCInvariant::C10(), vpMomentCInvariant::C2(), vpMomentCInvariant::C3(), vpMomentCInvariant::C4(), vpMomentCInvariant::C5(), vpMomentCInvariant::C6(), vpMomentCInvariant::C7(), vpMomentCInvariant::C8(), vpMomentCInvariant::C9(), vpMomentAlpha::compute(), vpMomentArea::compute(), vpMomentAreaNormalized::compute(), vpMomentCentered::compute(), vpMomentCInvariant::compute(), vpMomentGravityCenter::compute(), vpMomentGravityCenterNormalized::compute(), get(), vpMomentAlpha::get(), vpMomentCentered::get(), vpMomentCInvariant::get(), vpMomentGravityCenter::get(), vpMomentCInvariant::getMomentVector(), vpMomentGravityCenter::getXg(), vpMomentGravityCenter::getYg(), operator<<, vpMomentAlpha::operator<<, vpMomentArea::operator<<, vpMomentAreaNormalized::operator<<, vpMomentCentered::operator<<, vpMomentGravityCenter::operator<<, vpMomentGravityCenterNormalized::operator<<, vpMomentCInvariant::Px(), vpMomentCInvariant::Py(), vpMomentCentered::set(), vpMomentCInvariant::Sx(), vpMomentCInvariant::Sy(), vpMoment(), vpMomentAlpha::vpMomentAlpha(), vpMomentArea::vpMomentArea(), vpMomentAreaNormalized::vpMomentAreaNormalized(), vpMomentCInvariant::vpMomentCInvariant(), and vpMomentGravityCenter::vpMomentGravityCenter().