#include <visp3/core/vpLine.h>

Inheritance diagram for vpLine:

Public Types
enum	vpForwardProjectionDeallocatorType { user , vpDisplayForwardProjection }

Public Member Functions
	vpLine ()

void	changeFrame (const vpHomogeneousMatrix &cMo, vpColVector &cP) const VP_OVERRIDE

void	changeFrame (const vpHomogeneousMatrix &cMo) VP_OVERRIDE

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

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

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

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

vpLine *	duplicate () const VP_OVERRIDE

double	getRho () const

double	getTheta () const

void	setRho (double rho)

void	setTheta (double theta)

void	setWorldCoordinates (const double &oA1, const double &oB1, const double &oC1, const double &oD1, const double &oA2, const double &oB2, const double &oC2, const double &oD2)

void	setWorldCoordinates (const vpColVector &oP1, const vpColVector &oP2)

void	setWorldCoordinates (const vpColVector &oP) VP_OVERRIDE

void	projection () VP_OVERRIDE

void	projection (const vpColVector &cP, vpColVector &p) const VP_OVERRIDE

Public Member Functions Inherited from vpForwardProjection
vpColVector	get_oP () const

vpForwardProjectionDeallocatorType	getDeallocate ()

virtual void	print () const

void	project ()

void	project (const vpHomogeneousMatrix &cMo)

void	setDeallocate (vpForwardProjectionDeallocatorType d)

void	track (const vpHomogeneousMatrix &cMo)

Public Member Functions Inherited from vpTracker
vpColVector	get_p () const

vpColVector	get_cP () const

Public Attributes
Public Attributes Inherited from vpForwardProjection
vpColVector	oP

Public Attributes Inherited from vpTracker
vpColVector	p

vpColVector	cP

bool	cPAvailable

Protected Member Functions
void	init () VP_OVERRIDE

Detailed Description

Class that defines a 3D line in the object frame and allows forward projection of the line in the camera frame and in the 2D image plane by perspective projection. All the parameters must be set in meter.

Note that a 3D line is defined from the intersection between two 3D planes.

A 3D line has the followings parameters:

in the 3D object frame: parameters are located in vpForwardProjection::oP 8-dim internal vector. They correspond to the parameters oA1, oB1, oC1, oD1 and oA2, oB2, oC2, oD2 defining the equations of the two planes. Each point which belongs to the 3D line is a solution of those two equations:
$oA1*X + oB1*Y + oC1*Z + oD1 = 0$

$oA2*X + oB2*Y + oC2*Z + oD2 = 0$
To update these line parameters you may use setWorldCoordinates(). To get theses parameters use get_oP().
in the 3D camera frame: parameters are saved in vpTracker::cP 8-dim internal vector. They correspond to the parameters cA1, cB1, cC1, cD1 and cA2, cB2, cC2, cD2 defining the equations of the two planes. Each point which belongs to the 3D line is a solution of those two equations:
$cA1*X + cB1*Y + cC1*Z + cD1 = 0$

$cA2*X + cB2*Y + cC2*Z + cD2 = 0$
It is easily possible to compute these parameters thanks to the corresponding 3D parameters oP in the object frame. But you have to note that four constraints are added in the planes equations.
$cD1 = 0$

$cD2 > 0$

$cA1*cA2 + cB1*cB2 + cC1*cC2 = 0$

$|| cA2 || = 1$
To compute these parameters you may use changeFrame(). To get these parameters use get_cP().
in the 2D image plane: parameters are saved in vpTracker::p 2-dim vector. They correspond to the parameters ( $\rho$ , $\theta$ ). These 2D parameters are obtained from the perspective projection of the 3D line parameters expressed in the camera frame. They are defined thanks to the 2D equation of a line.
$x \; cos(\theta) + y \; sin(\theta) -\rho = 0$
Here and are the coordinates of a point belonging to the line in the image plane while $\rho$ and $\theta$ are the parameters used to define the line. The value of $\theta$ is between $-\pi/2$ and $\pi/2$ and the value of $\rho$ can be positive or negative. The conventions used to choose the sign of $\rho$ and the value of $\theta$ are illustrated by the following image.

The line parameters corresponding to the image frame are located in the vpTracker::p public attribute, where p is a vector defined as:

$p = \left[\begin{array}{c} \rho \\ \theta \end{array}\right]$

To compute these parameters use projection(). To get the corresponding values use get_p().

Examples: manGeometricFeatures.cpp, servoAfma6Line2DCamVelocity.cpp, servoSimuLine2DCamVelocityDisplay.cpp, servoSimuSquareLine2DCamVelocityDisplay.cpp, and testPoseFeatures.cpp.

Definition at line 102 of file vpLine.h.

Member Enumeration Documentation

◆ vpForwardProjectionDeallocatorType

enum vpForwardProjection::vpForwardProjectionDeallocatorType

inherited

Used for memory issue especially in the vpServo class.

Enumerator
user
vpDisplayForwardProjection

Definition at line 70 of file vpForwardProjection.h.

Constructor & Destructor Documentation

◆ vpLine()

vpLine::vpLine ( )

Default constructor.

Definition at line 65 of file vpLine.cpp.

References init().

Referenced by duplicate().

Member Function Documentation

◆ changeFrame() [1/2]

void vpLine::changeFrame ( const vpHomogeneousMatrix & cMo )

virtual

Computes the line parameters cP in the camera frame thanks to the line parameters oP given in the object frame and the homogeneous matrix relative to the pose cMo between the object frame and the camera frame. Thus the computation gives the equations of the two planes needed to define the line in the camera frame thanks to the equations of the same two planes in the object frame.

In input of this method, the line parameters oP in the object frame are those from the vpForwardProjection::oP public attribute.

As a result of this method, line parameters cP in the camera frame are updated in the vpTracker::cP public attribute.

Parameters

cMo	: The homogeneous matrix corresponding to the pose between the camera frame and the object frame.

The code below shows how to use this method.

//Create the line
vpLine line;
 
//Set the coordinates of the line in the object frame in meter.
line.setWorldCoordinates( 1, 0, 0, -0.5, 0, 0, 1, 0.5)
//The line is define by the intersection between the plane X = 0.5m and Z =
0.5m
 
//Create the homogeneous matrix
vpHomogeneousMatrix cMo;
//Computes or set here the homogeneous matrix
 
//Computes the equations of the two planes in the camera frame
line.changeFrame(cMo);

Implements vpForwardProjection.

Definition at line 306 of file vpLine.cpp.

References changeFrame(), and vpTracker::cP.

◆ changeFrame() [2/2]

void vpLine::changeFrame	(	const vpHomogeneousMatrix &	cMo,
		vpColVector &	cP_
	)		const

virtual

Computes the line parameters cP in the camera frame thanks to the line parameters oP given in the object frame and the homogeneous matrix relative to the pose between the camera frame and the object frame. Thus the computation gives the equations of the two planes needed to define the line in the desired frame thanks to the equations of the same two planes in the object frame.

In input of this method, the line parameters oP in the object frame are those from the vpForwardProjection::oP public attribute.

Parameters

cMo	: The homogeneous matrix relative to the pose between the desired frame and the object frame.
cP_	: The vector which will contain the parameters of the two planes in the camera frame. $cP = \left[\begin{array}{c}cA1 \\ cB1 \\ cC1 \\ cD1 \\ cA2 \\ cB2 \\ cC2 \\ cD2 \end{array}\right]$

The code below shows how to use this method.

//Create the line
vpLine line;
 
//Set the coordinates of the line in the object frame in meter.
line.setWorldCoordinates( 1, 0, 0, -0.5, 0, 0, 1, 0.5)
//The line is define by the intersection between the plane X = 0.5m and Z = 0.5m
 
//Create the homogeneous matrix
vpHomogeneousMatrix cMo;
//Computes or set here the homogeneous matrix
 
//Creates the vector which will contain the line features
vpColVector cP(8);
 
//Computes the equations of the two planes in the camera frame
line.changeFrame(cMo, cP);

Implements vpForwardProjection.

Definition at line 348 of file vpLine.cpp.

References vpForwardProjection::oP, and vpColVector::resize().

Referenced by changeFrame(), vpMbtDistanceLine::computeInteractionMatrixError(), display(), vpMbtDistanceLine::initMovingEdge(), and vpMbtDistanceLine::updateMovingEdge().

◆ display() [1/4]

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

virtual

Displays the line in the image I thanks to the 2D parameters of the line p in the image plane (vpTracker::p) and the camera parameters which enable to convert the parameters from meter to pixel.

Parameters

I	: The image where the line must be displayed.
cam	: The camera parameters to enable the conversion from meter to pixel.
color	: The desired color to display the line in the image.
thickness	: Thickness of the feature representation.

Implements vpForwardProjection.

Examples: manGeometricFeatures.cpp.

Definition at line 466 of file vpLine.cpp.

References vpFeatureDisplay::displayLine(), and vpTracker::p.

◆ display() [2/4]

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

virtual

Displays the line in the image I thanks to the parameters in the object frame (vpForwardProjection::oP), the homogeneous matrix relative to the pose between the camera frame and the object frame and the camera parameters which enable to convert the features from meter to pixel.

This method is non destructive wrt. cP and p internal line parameters.

Parameters

I	: The image where the line must be displayed in overlay.
cMo	: The homogeneous matrix corresponding to the pose between the camera frame and the object frame.
cam	: The camera parameters to enable the conversion from meter to pixel.
color	: The desired color to display the line in the image.
thickness	: Thickness of the feature representation.

Implements vpForwardProjection.

Definition at line 515 of file vpLine.cpp.

References changeFrame(), vpFeatureDisplay::displayLine(), and projection().

◆ display() [3/4]

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

Displays the line in the image I thanks to the 2D parameters of the line p in the image plane (vpTracker::p) and the camera parameters which enable to convert the parameters from meter to pixel.

Parameters

I	: The image where the line must be displayed.
cam	: The camera parameters to enable the conversion from meter to pixel.
color	: The desired color to display the line in the image.
thickness	: Thickness of the feature representation.

Definition at line 487 of file vpLine.cpp.

References vpFeatureDisplay::displayLine(), and vpTracker::p.

◆ display() [4/4]

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

Displays the line in the image I thanks to the parameters in the object frame (vpForwardProjection::oP), the homogeneous matrix relative to the pose between the camera frame and the object frame and the camera parameters which enable to convert the features from meter to pixel.

This method is non destructive wrt. cP and p internal line parameters.

Parameters

I	: The image where the line must be displayed in overlay.
cMo	: The homogeneous matrix corresponding to the pose between the camera frame and the object frame.
cam	: The camera parameters to enable the conversion from meter to pixel.
color	: The desired color to display the line in the image.
thickness	: Thickness of the feature representation.

Definition at line 551 of file vpLine.cpp.

References changeFrame(), vpFeatureDisplay::displayLine(), and projection().

◆ duplicate()

vpLine * vpLine::duplicate ( ) const

virtual

Create an object with the same type.

vpForwardProjection *fp;
vpLine line;
fp = line.duplicate(); // fp is now a vpLine

Implements vpForwardProjection.

Definition at line 575 of file vpLine.cpp.

References vpLine().

◆ get_cP()

vpColVector vpTracker::get_cP ( ) const

inlineinherited

Return object parameters expressed in the 3D camera frame.

Definition at line 95 of file vpTracker.h.

◆ get_oP()

vpColVector vpForwardProjection::get_oP ( ) const

inlineinherited

Return object parameters expressed in the 3D object frame.

Definition at line 155 of file vpForwardProjection.h.

◆ get_p()

vpColVector vpTracker::get_p ( ) const

inlineinherited

Return object parameters expressed in the 2D image plane computed by perspective projection.

Definition at line 93 of file vpTracker.h.

◆ getDeallocate()

vpForwardProjectionDeallocatorType vpForwardProjection::getDeallocate ( )

inlineinherited

Definition at line 157 of file vpForwardProjection.h.

◆ getRho()

double vpLine::getRho ( ) const

inline

Gets the $\rho$ value corresponding to one of the two parameters used to define the line parametrization in the image plane.

Returns: Returns the current value of $\rho$ .

See also: getTheta()

Definition at line 132 of file vpLine.h.

Referenced by vpFeatureBuilder::create(), vpMbtDistanceLine::initMovingEdge(), and vpMbtDistanceLine::updateMovingEdge().

◆ getTheta()

double vpLine::getTheta ( ) const

inline

Gets the $\theta$ angle value corresponding to one of the two parameters used to define the line parametrization in the image plane.

Returns: Returns the current value of $\theta$ .

See also: getRho()

Definition at line 143 of file vpLine.h.

Referenced by vpFeatureBuilder::create(), vpMbtDistanceLine::initMovingEdge(), and vpMbtDistanceLine::updateMovingEdge().

◆ init()

BEGIN_VISP_NAMESPACE void vpLine::init ( )

protectedvirtual

Initialize the memory space requested for the 2D line parameters (p) in the image plane and for 3D line parameters (oP and cP) respectively in the object frame and the camera frame.

Implements vpForwardProjection.

Definition at line 53 of file vpLine.cpp.

References vpTracker::cP, vpForwardProjection::oP, vpTracker::p, and vpColVector::resize().

Referenced by vpLine().

◆ print()

BEGIN_VISP_NAMESPACE void vpForwardProjection::print ( ) const

virtualinherited

Print to stdout the feature parameters in:

the object frame
the camera frame
the image plane.

Examples: servoSimuCircle2DCamVelocityDisplay.cpp, servoSimuLine2DCamVelocityDisplay.cpp, and servoSimuSquareLine2DCamVelocityDisplay.cpp.

Definition at line 49 of file vpForwardProjection.cpp.

References vpTracker::cP, vpForwardProjection::oP, vpTracker::p, and vpColVector::t().

◆ project() [1/2]

void vpForwardProjection::project ( )

inherited

Compute the feature parameters in the image plane (vpTracker::p) from the parameters in the camera frame (vpTracker::cP).

Warning: Be careful to update vpTracker::p and vpTracker::cP public attributes before the call of this method.

Examples: catchPoseRansac2.cpp, homographyHLM2DObject.cpp, homographyHLM3DObject.cpp, homographyHartleyDLT2DObject.cpp, manGeometricFeatures.cpp, manServo4PointsDisplay.cpp, manSimu4Points.cpp, servoAfma62DhalfCamVelocity.cpp, servoAfma6Cylinder2DCamVelocity.cpp, servoAfma6Cylinder2DCamVelocitySecondaryTask.cpp, servoAfma6Line2DCamVelocity.cpp, servoPioneerPanSegment3D.cpp, simulateFourPoints2DPolarCamVelocity.cpp, testFeatureSegment.cpp, testFindMatch.cpp, and testPoseFeatures.cpp.

Definition at line 64 of file vpForwardProjection.cpp.

References vpTracker::cP, vpTracker::p, and vpForwardProjection::projection().

Referenced by vpMbtFaceDepthNormal::computeNormalVisibility(), vpMbtFaceDepthDense::computeROI(), vpMbtFaceDepthNormal::displayFeature(), vpMbtFaceDepthNormal::getFeaturesForDisplay(), vpKeyPoint::matchPointAndDetect(), vpMbtFaceDepthNormal::planeIsInvalid(), and vpForwardProjection::track().

◆ project() [2/2]

void vpForwardProjection::project ( const vpHomogeneousMatrix & cMo )

inherited

Compute the feature parameters in the camera frame (vpTracker::cP) and than compute the projection of these parameters in the image plane (vpTracker::p).

Warning: The feature parameters in the object frame (vpForwardProjection:oP) need to be set prior the use of this method. To initialize these parameters see setWorldCoordinates().

Parameters

cMo	: The homogeneous matrix corresponding to the pose between the camera frame and the object frame.

Definition at line 80 of file vpForwardProjection.cpp.

References vpForwardProjection::changeFrame(), and vpForwardProjection::projection().

◆ projection() [1/2]

void vpLine::projection ( )

virtual

Computes the 2D parameters p of the line in the image plane thanks to the 3D line parameters cP in the camera frame located in the vpTracker::cP public attribute. The parameters $p=(\rho, \theta)$ are updated in the vpTracker::p public attribute.

Warning: To compute these parameters p, the method exploit the feature parameters cP in the camera frame. Thus, vpTracker::cP need to be updated before the call of this method. For that, a call to changeFrame(const vpHomogeneousMatrix &) is requested.

The code below shows how to use this method.

//Create the line
vpLine line;
 
//Set the coordinates of the line in the object frame in meter.
line.setWorldCoordinates( 1, 0, 0, -0.5, 0, 0, 1, 0.5)
//Here the line is define by the intersection between the plane X = 0.5m and
Z = 0.5m
 
//Create the homogeneous matrix
vpHomogeneousMatrix cMo;
//Computes or set here the homogeneous matrix
 
//Computes the equations of the two planes in the camera frame
line.changeFrame(cMo);
 
//Computes the line features in the camera frame( rho and theta)
line.projection();

Implements vpForwardProjection.

Definition at line 201 of file vpLine.cpp.

References vpTracker::cP, and vpTracker::p.

Referenced by vpMbtDistanceLine::computeInteractionMatrixError(), display(), vpMbtDistanceLine::initMovingEdge(), and vpMbtDistanceLine::updateMovingEdge().

◆ projection() [2/2]

void vpLine::projection	(	const vpColVector &	cP_,
		vpColVector &	p_
	)		const

virtual

Computes the 2D parameters p of the line in the image plane thanks to the 3D line parameters cP expressed in the camera frame. The image plane parameters $p=(\rho , \theta)$ are updated in output.

Parameters

[in]	cP_	: The vector containing the line parameters relative to the camera frame. $cP = \left[\begin{array}{c}cA1 \\ cB1 \\ cC1 \\ cD1 \\ cA2 \\ cB2 \\ cC2 \\ cD2 \end{array}\right]$
[out]	p_	: The vector which contains the 2D line features expressed in the image plane. $p = \left[\begin{array}{c} \rho \\ \theta \end{array}\right]$

Exceptions

vpException::fatalError : Degenerate case, the image of the straight line is a point.

Implements vpForwardProjection.

Definition at line 221 of file vpLine.cpp.

References vpTracker::cP, vpException::dimensionError, vpException::fatalError, vpArray2D< Type >::getRows(), and vpColVector::resize().

◆ setDeallocate()

void vpForwardProjection::setDeallocate ( vpForwardProjectionDeallocatorType d )

inlineinherited

Definition at line 185 of file vpForwardProjection.h.

◆ setRho()

void vpLine::setRho ( double rho )

inline

Sets the $\rho$ parameter used to define the line in the image plane.

Parameters

rho	: The desired value for $\rho$ .

See also: setTheta()

Definition at line 153 of file vpLine.h.

◆ setTheta()

void vpLine::setTheta ( double theta )

inline

Sets the $\theta$ angle value used to define the line in the image plane.

Parameters

theta : The desired value for $\theta$ angle.

See also: setRho()

Definition at line 163 of file vpLine.h.

◆ setWorldCoordinates() [1/3]

void vpLine::setWorldCoordinates	(	const double &	oA1,
		const double &	oB1,
		const double &	oC1,
		const double &	oD1,
		const double &	oA2,
		const double &	oB2,
		const double &	oC2,
		const double &	oD2
	)

Sets the parameters oP which define the line in the object frame. As said in the class description, the line is defined as the intersection of two planes. The different parameters here define the equations of the two planes in the object frame. They are used to set the vpForwardProjection::oP public attribute.

$oA1 X + oB1 Y + oC1 Z + oD1 = 0$

$oA2 X + oB2 Y + oC2 Z + oD2 = 0$

Here $ (X, Y, Z) $ are the 3D coordinates of a point in the object frame.

Parameters

oA1,oB1,oC1,oD1	: The parameters used to define the first plane in the object frame.
oA2,oB2,oC2,oD2	: The parameters used to define the second plane in the object frame.

Examples: manGeometricFeatures.cpp, servoAfma6Line2DCamVelocity.cpp, servoSimuLine2DCamVelocityDisplay.cpp, servoSimuSquareLine2DCamVelocityDisplay.cpp, and testPoseFeatures.cpp.

Definition at line 83 of file vpLine.cpp.

References vpForwardProjection::oP.

◆ setWorldCoordinates() [2/3]

void vpLine::setWorldCoordinates ( const vpColVector & oP_ )

virtual

Sets the parameters oP which define the line in the object frame. As said in the class description, the line is defined as the intersection of two planes. Eight parameters are required to define the equations of the two planes in the object frame. They are used to set the vpForwardProjection::oP public attribute.

$oA1 X + oB1 Y + oC1 Z + oD1 = 0$

$oA2 X + oB2 Y + oC2 Z + oD2 = 0$

Here $ (X, Y, Z) $ are the 3D coordinates of a point in the object frame.

Parameters

oP_	: The column vector which contains the eight parameters needed to define the equations of the two planes in the object frame. $oP = \left[\begin{array}{c}oA1 \\ oB1 \\ oC1 \\ oD1 \\ oA2 \\ oB2 \\ oC2 \\ oD2 \end{array}\right]$

Implements vpForwardProjection.

Definition at line 123 of file vpLine.cpp.

References vpException::dimensionError, vpArray2D< Type >::getRows(), and vpForwardProjection::oP.

◆ setWorldCoordinates() [3/3]

void vpLine::setWorldCoordinates	(	const vpColVector &	oP1,
		const vpColVector &	oP2
	)

Sets the parameters oP which define the line in the object frame. As said in the class description, the line is defined as the intersection of two planes. Eight parameters are required to define the equations of the two planes in the object frame. They are used to set the vpForwardProjection::oP public attribute.

$oA1 X + oB1 Y + oC1 Z + oD1 = 0$

$oA2 X + oB2 Y + oC2 Z + oD2 = 0$

Here $ (X, Y, Z) $ are the 3D coordinates of a point in the object frame.

Parameters

oP1	: The column vector which contains the four parameters needed to define the equations of the first plane in the object frame. $oP1 = \left[\begin{array}{c}oA1 \\ oB1 \\ oC1 \\ oD1 \end{array}\right]$
oP2	: The column vector which contains the four parameters needed to define the equations of the second plane in the object frame. $oP2 = \left[\begin{array}{c} oA2 \\ oB2 \\ oC2 \\ oD2 \end{array}\right]$

Definition at line 153 of file vpLine.cpp.

References vpException::dimensionError, vpArray2D< Type >::getRows(), and vpForwardProjection::oP.

◆ track()

void vpForwardProjection::track ( const vpHomogeneousMatrix & cMo )

inherited

Track the feature parameters in the camera frame (vpTracker::cP) and than compute the projection of these parameters in the image plane (vpTracker::p).

This method is similar to project(const vpHomogeneousMatrix &).

Warning: The feature parameters in the object frame (vpForwardProjection:oP) need to be set prior the use of this method. To initialize these parameters see setWorldCoordinates().

Parameters