ViSP  2.6.2
vpMomentBasic Class Reference

#include <vpMomentBasic.h>

+ Inheritance diagram for vpMomentBasic:

Public Member Functions

 vpMomentBasic ()
void compute ()
std::vector< double > & get ()
double get (unsigned int i, unsigned int j)
const char * name ()
vpMomentObjectgetObject ()
void linkTo (vpMomentDatabase &moments)
void update (vpMomentObject &object)

Protected Member Functions

vpMomentDatabasegetMoments ()

Protected Attributes

std::vector< double > values

Detailed Description

This class defines the 2D basic moment $m_{ij}$. This class is a wrapper for vpMomentObject wich allows to use it as a moment. This enables all common operations such as adding to a vpMomentDatabase.

In the case of a dense object O, 2D basic moments are defined by:

\[m_{ij} = \int \int_{O} x^j y^j dx dy\]

In the case of a discrete set of n points, the basic moments are defined by

\[m_{ij} = \sum_{k=1}^{n} x_k^j y_k^j \]

The selection of a dense or discrete object is done in vpMomentObject. The maximum order of vpMomentBasic is the same as that of vpMomentObject (ie: $i+j \leq $ vpMomentObject::getOrder).

Note that in the continuous case, the basic moment $m_{00}$ corresponds to the surface $a$ of the object. In the discrete case, it is the number of discrete points $n$.

Definition at line 74 of file vpMomentBasic.h.

Constructor & Destructor Documentation

vpMomentBasic::vpMomentBasic ( )

Default constructor.

Definition at line 47 of file vpMomentBasic.cpp.

Member Function Documentation

void vpMomentBasic::compute ( )

Dummy function. Everything is already done in object.

Implements vpMoment.

Definition at line 76 of file vpMomentBasic.cpp.

std::vector< double > & vpMomentBasic::get ( )

Retrieve all moments of all orders computed. vpMomentBasic::get()[j*order+i] refers to moment $m_{ij}$.

all computed moments.

Same behaviour as vpMomentObject.

Definition at line 57 of file vpMomentBasic.cpp.

References vpMomentObject::get(), and vpMoment::getObject().

double vpMomentBasic::get ( unsigned int  i,
unsigned int  j 

Gets the desired moment using indexes.

i: first index of the 2D moment.
j: second index of the 2D moment.
$m_{ij}$ moment.

Same behaviour as vpMomentObject.

Definition at line 69 of file vpMomentBasic.cpp.

References vpMomentObject::get(), and vpMoment::getObject().

vpMomentDatabase& vpMoment::getMoments ( )
void vpMoment::linkTo ( vpMomentDatabase moments)

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.

Two moments of the same class cannot be stored in the same database
#include <visp/vpMomentObject.h>
#include <visp/vpPoint.h>
#include <visp/vpMomentGravityCenter.h>
#include <visp/vpMomentDatabase.h>
#include <visp/vpMomentCentered.h>
int main()
std::vector<vpPoint> vec_p;
p.set_x(1); p.set_y(1); // coordinates in meters in the image plane (vertex 1)
p.set_x(2); p.set_y(2); // coordinates in meters in the image plane (vertex 2)
obj.setType(vpMomentObject::DISCRETE); // Discrete mode.
obj.fromVector(vec_p); // Init the dense object with the polygon
vpMomentGravityCenter G; // declaration of gravity center
vpMomentCentered mc; // mc containts 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;
moments: database of moment primitives.

Definition at line 104 of file vpMoment.cpp.

References vpMoment::name().

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

const char* vpMomentBasic::name ( )

Moment name.

Implements vpMoment.

Definition at line 84 of file vpMomentBasic.h.

void vpMoment::update ( vpMomentObject object)

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

object: object descriptor of the current camera vision.

Definition at line 117 of file vpMoment.cpp.

Member Data Documentation