#include <visp3/vision/vpCalibration.h>

Public Types
enum	vpCalibrationMethodType { CALIB_LAGRANGE, CALIB_VIRTUAL_VS, CALIB_VIRTUAL_VS_DIST, CALIB_LAGRANGE_VIRTUAL_VS, CALIB_LAGRANGE_VIRTUAL_VS_DIST }

Public Member Functions
	vpCalibration ()

	vpCalibration (const vpCalibration &c)

virtual	~vpCalibration ()

int	addPoint (double X, double Y, double Z, vpImagePoint &ip)

vpCalibration &	operator= (const vpCalibration &twinCalibration)

int	clearPoint ()

void	computeStdDeviation (double &deviation, double &deviation_dist)

int	computeCalibration (vpCalibrationMethodType method, vpHomogeneousMatrix &cMo_est, vpCameraParameters &cam_est, bool verbose=false)

double	computeStdDeviation (const vpHomogeneousMatrix &cMo_est, const vpCameraParameters &camera)

double	computeStdDeviation_dist (const vpHomogeneousMatrix &cMo, const vpCameraParameters &cam)

int	displayData (vpImage< unsigned char > &I, vpColor color=vpColor::red, unsigned int thickness=1, int subsampling_factor=1)

int	displayGrid (vpImage< unsigned char > &I, vpColor color=vpColor::yellow, unsigned int thickness=1, int subsampling_factor=1)

double	getResidual (void) const

double	getResidual_dist (void) const

unsigned int	get_npt () const

int	init ()

int	readData (const char *filename)

int	writeData (const char *filename)

Static Public Member Functions
static void	calibrationTsai (std::vector< vpHomogeneousMatrix > &cMo, std::vector< vpHomogeneousMatrix > &rMe, vpHomogeneousMatrix &eMc)

static int	computeCalibrationMulti (vpCalibrationMethodType method, std::vector< vpCalibration > &table_cal, vpCameraParameters &cam, double &globalReprojectionError, bool verbose=false)

static int	computeCalibrationTsai (std::vector< vpCalibration > &table_cal, vpHomogeneousMatrix &eMc, vpHomogeneousMatrix &eMc_dist)

static double	getLambda ()

static int	readGrid (const char *filename, unsigned int &n, std::list< double > &oX, std::list< double > &oY, std::list< double > &oZ, bool verbose=false)

static void	setLambda (const double &lambda)

Public Attributes
vpHomogeneousMatrix	cMo

vpHomogeneousMatrix	cMo_dist

vpCameraParameters	cam

vpCameraParameters	cam_dist

vpHomogeneousMatrix	rMe

vpHomogeneousMatrix	eMc

vpHomogeneousMatrix	eMc_dist

Detailed Description

Tools for perspective camera calibration.

Definition at line 71 of file vpCalibration.h.

Member Enumeration Documentation

enum vpCalibration::vpCalibrationMethodType

Minimization algorithm use to estimate the camera parameters.

Enumerator
CALIB_LAGRANGE	Lagrange approach without estimation of the distortion.
CALIB_VIRTUAL_VS	Virtual visual servoing approach without estimation of the distortion (results are similar to Lowe approach).
CALIB_VIRTUAL_VS_DIST	Virtual visual servoing approach with estimation of the distortion.
CALIB_LAGRANGE_VIRTUAL_VS	Lagrange approach first, than virtual visual servoing approach, without estimation of the distortion.
CALIB_LAGRANGE_VIRTUAL_VS_DIST	Lagrange approach first, than virtual visual servoing approach, with estimation of the distortion.

Definition at line 77 of file vpCalibration.h.

Constructor & Destructor Documentation

vpCalibration::vpCalibration ( )

Default constructor.

Definition at line 74 of file vpCalibration.cpp.

References init().

vpCalibration::vpCalibration ( const vpCalibration & c )

Copy constructor.

Definition at line 83 of file vpCalibration.cpp.

vpCalibration::~vpCalibration ( )

virtual

Destructor : delete the array of point (freed the memory)

Definition at line 94 of file vpCalibration.cpp.

References clearPoint().

Member Function Documentation

int vpCalibration::addPoint	(	double	X,
		double	Y,
		double	Z,
		vpImagePoint &	ip
	)

Add a new point in the array of points.

Parameters

X,Y,Z	: 3D coordinates of a point in the object frame
ip	: 2D Coordinates of the point in the camera frame.

Definition at line 149 of file vpCalibration.cpp.

Referenced by readData().

void vpCalibration::calibrationTsai	(	std::vector< vpHomogeneousMatrix > &	cMo,
		std::vector< vpHomogeneousMatrix > &	rMe,
		vpHomogeneousMatrix &	eMc
	)

static

calibration method of effector-camera from R. Tsai and R. Lorenz [31].

Compute extrinsic camera parameters : the constant transformation from the effector to the camera coordinates (eMc).

Parameters

cMo	: vector of homogeneous matrices representing the transformation between the camera and the scene (input)
rMe	: vector of homogeneous matrices representing the transformation between the effector (where the camera is fixed) and the reference coordinates (base of the manipulator) (input). Must be the same size as cMo.
eMc	: homogeneous matrix representing the transformation between the effector and the camera (output)

Examples:: calibrateTsai.cpp.

Definition at line 1137 of file vpCalibrationTools.cpp.

References vpMatrix::AtA(), vpException::dimensionError, vpRotationMatrix::eye(), vpHomogeneousMatrix::insert(), vpMatrix::pseudoInverse(), vpMath::sinc(), vpArray2D< Type >::size(), vpColVector::skew(), vpMatrix::stack(), vpColVector::stack(), vpColVector::sumSquare(), vpRotationMatrix::t(), and vpMatrix::t().

Referenced by computeCalibrationTsai().

int vpCalibration::clearPoint ( )

Suppress all the point in the array of point.

Delete the array of points.

Definition at line 132 of file vpCalibration.cpp.

Referenced by readData(), and ~vpCalibration().

int vpCalibration::computeCalibration	(	vpCalibrationMethodType	method,
		vpHomogeneousMatrix &	cMo_est,
		vpCameraParameters &	cam_est,
		bool	verbose = `false`
	)

Compute the calibration according to the desired method using one pose.

Parameters

method	: Method that will be used to estimate the parameters.
cMo_est	: estimated homogeneous matrix that defines the pose.
cam_est	: estimated intrinsic camera parameters.
verbose	: set at true if information about the residual at each loop of the algorithm is hoped.

Returns: 0 if the calibration computation succeed.

Definition at line 366 of file vpCalibration.cpp.

References CALIB_LAGRANGE, CALIB_LAGRANGE_VIRTUAL_VS, CALIB_LAGRANGE_VIRTUAL_VS_DIST, CALIB_VIRTUAL_VS, CALIB_VIRTUAL_VS_DIST, cam, cam_dist, cMo, cMo_dist, and vpCameraParameters::printParameters().

int vpCalibration::computeCalibrationMulti	(	vpCalibrationMethodType	method,
		std::vector< vpCalibration > &	table_cal,
		vpCameraParameters &	cam_est,
		double &	globalReprojectionError,
		bool	verbose = `false`
	)

static

Compute the multi-images calibration according to the desired method using many poses.

Parameters

method	: Method used to estimate the camera parameters.
table_cal	: Vector of vpCalibration.
cam_est	: Estimated intrinsic camera parameters.
globalReprojectionError	: Global reprojection error or global residual.
verbose	: Set at true if information about the residual at each loop of the algorithm is hoped.

Returns: 0 if the computation was managed succeed.

Definition at line 459 of file vpCalibration.cpp.

References CALIB_LAGRANGE, CALIB_LAGRANGE_VIRTUAL_VS, CALIB_LAGRANGE_VIRTUAL_VS_DIST, CALIB_VIRTUAL_VS, CALIB_VIRTUAL_VS_DIST, cMo, get_npt(), and vpCameraParameters::printParameters().

int vpCalibration::computeCalibrationTsai	(	std::vector< vpCalibration > &	table_cal,
		vpHomogeneousMatrix &	eMc,
		vpHomogeneousMatrix &	eMc_dist
	)

static

Compute the multi-image calibration of effector-camera from R. Tsai and R. Lenz [31].

Compute extrinsic camera parameters : the constant transformation from the end-effector to the camera frame ${^e}{\bf M}_c$ considering the camera model with or without distortion.

Parameters

[in]	table_cal	: Vector of vpCalibration that contains for each index a couple of ${^r}{\bf M}_e$ (world to end-effector) and ${^c}{\bf M}_o$ (camera to object) transformations.
[out]	eMc	: Estimated pose of the camera in relation to the end-effector considering the camera model without distortion.
[out]	eMc_dist	: Estimated pose of the camera in relation to the end-effector considering the model with distortion.

Returns: 0 if the computation managed, -1 if less than three poses are provides as input.

Definition at line 560 of file vpCalibration.cpp.

References calibrationTsai(), and vpERROR_TRACE.

void vpCalibration::computeStdDeviation	(	double &	deviation,
		double &	deviation_dist
	)

Compute and return the standard deviation expressed in pixel for pose matrix and camera intrinsic parameters.

Parameters

deviation	: the standard deviation computed for the model without distortion.
deviation_dist	: the standard deviation computed for the model with distortion.

Definition at line 348 of file vpCalibration.cpp.

References cam, cam_dist, cMo, cMo_dist, and computeStdDeviation_dist().

double vpCalibration::computeStdDeviation	(	const vpHomogeneousMatrix &	cMo_est,
		const vpCameraParameters &	camera
	)

Compute and return the standard deviation expressed in pixel for pose matrix and camera intrinsic parameters for model without distortion.

Parameters

cMo_est	: the matrix that defines the pose to be tested.
camera	: camera intrinsic parameters to be tested.

Returns: the standard deviation by point of the error in pixel .

Definition at line 226 of file vpCalibration.cpp.

References vpCameraParameters::get_px(), vpCameraParameters::get_py(), vpImagePoint::get_u(), vpCameraParameters::get_u0(), vpImagePoint::get_v(), vpCameraParameters::get_v0(), and vpMath::sqr().

double vpCalibration::computeStdDeviation_dist	(	const vpHomogeneousMatrix &	cMo_est,
		const vpCameraParameters &	camera
	)

Compute and return the standard deviation expressed in pixel for pose matrix and camera intrinsic parameters with pixel to meter model.

Parameters

cMo_est	: the matrix that defines the pose to be tested.
camera	: camera intrinsic parameters to be tested.

Returns: the standard deviation by point of the error in pixel .

Definition at line 279 of file vpCalibration.cpp.

References vpCameraParameters::get_kdu(), vpCameraParameters::get_kud(), vpCameraParameters::get_px(), vpCameraParameters::get_py(), vpImagePoint::get_u(), vpCameraParameters::get_u0(), vpImagePoint::get_v(), vpCameraParameters::get_v0(), and vpMath::sqr().

Referenced by computeStdDeviation().

int vpCalibration::displayData	(	vpImage< unsigned char > &	I,
		vpColor	color = `vpColor::red`,
		unsigned int	thickness = `1`,
		int	subsampling_factor = `1`
	)

Display the data of the calibration (center of the tracked dots)

Parameters

I	: Image where to display data.
color	: Color of the data.
thickness	: Thickness of the displayed data.
subsampling_factor	: Subsampling factor. Default value is 1. Admissible values are multiple of 2. Divide by this parameter the coordinates of the data points resulting from image processing.

Definition at line 745 of file vpCalibration.cpp.

References vpDisplay::displayCross(), vpImagePoint::get_u(), vpImagePoint::get_v(), vpImagePoint::set_u(), and vpImagePoint::set_v().

int vpCalibration::displayGrid	(	vpImage< unsigned char > &	I,
		vpColor	color = `vpColor::yellow`,
		unsigned int	thickness = `1`,
		int	subsampling_factor = `1`
	)

Display estimated centers of dots using intrinsic camera parameters with model with distortion and the computed pose.

Parameters

I	: Image where to display grid data.
color	: Color of the data.
thickness	: Thickness of the displayed data.
subsampling_factor	: Subsampling factor. Default value is 1. Admissible values are multiple of 2. Divide by this parameter the values of the camera parameters.

Definition at line 770 of file vpCalibration.cpp.

References cam_dist, cMo_dist, vpDisplay::displayCross(), vpCameraParameters::get_kud(), vpCameraParameters::get_px(), vpCameraParameters::get_py(), vpCameraParameters::get_u0(), vpCameraParameters::get_v0(), vpImagePoint::set_u(), and vpMath::sqr().

unsigned int vpCalibration::get_npt ( ) const

inline

get the number of points

Definition at line 152 of file vpCalibration.h.

Referenced by computeCalibrationMulti().

static double vpCalibration::getLambda ( )

inlinestatic

Set the gain for the virtual visual servoing algorithm.

Definition at line 145 of file vpCalibration.h.

double vpCalibration::getResidual ( void ) const

inline

get the residual in pixels

Definition at line 148 of file vpCalibration.h.

double vpCalibration::getResidual_dist ( void ) const

inline

get the residual for perspective projection with distortion (in pixels)

Definition at line 150 of file vpCalibration.h.

int vpCalibration::init ( void )

Basic initialisation (called by the constructors)

Definition at line 57 of file vpCalibration.cpp.

Referenced by vpCalibration().

vpCalibration & vpCalibration::operator= ( const vpCalibration & twinCalibration )

= operator.

Parameters

twinCalibration : object to be copied

Definition at line 104 of file vpCalibration.cpp.

References cam, cam_dist, cMo, cMo_dist, eMc, eMc_dist, and rMe.

int vpCalibration::readData ( const char * filename )

Read data from disk : data are organized as follow oX oY oZ u v

Parameters

filename : name of the file

Definition at line 643 of file vpCalibration.cpp.

References addPoint(), vpException::badValue, clearPoint(), vpImagePoint::set_u(), and vpImagePoint::set_v().

int vpCalibration::readGrid	(	const char *	filename,
		unsigned int &	n,
		std::list< double > &	oX,
		std::list< double > &	oY,
		std::list< double > &	oZ,
		bool	verbose = `false`
	)

static

Read calibration grid coordinates from disk : data are organized as follow oX oY oZ

Parameters

filename	: name of the file
n	: number of points in the calibration grid
oX	: List of oX coordinates
oY	: List of oY coordinates
oZ	: List of oZ coordinates
verbose	: Additionnal printings if true (number of points on the calibration grid and their respective coordinates in the object frame).