#include <visp3/core/vpCameraParameters.h>

Public Types
enum	vpCameraParametersProjType { perspectiveProjWithoutDistortion , perspectiveProjWithDistortion , ProjWithKannalaBrandtDistortion }

Public Member Functions
	vpCameraParameters ()

	vpCameraParameters (const vpCameraParameters &c)

	vpCameraParameters (double px, double py, double u0, double v0)

	vpCameraParameters (double px, double py, double u0, double v0, double kud, double kdu)

	vpCameraParameters (double px, double py, double u0, double v0, const std::vector< double > &distortion_coefficients)

vpCameraParameters &	operator= (const vpCameraParameters &c)

bool	operator== (const vpCameraParameters &c) const

bool	operator!= (const vpCameraParameters &c) const

virtual	~vpCameraParameters ()

void	init ()

void	init (const vpCameraParameters &c)

void	initFromCalibrationMatrix (const vpMatrix &_K)

void	initFromFov (const unsigned int &w, const unsigned int &h, const double &hfov, const double &vfov)

void	initPersProjWithoutDistortion (double px, double py, double u0, double v0)

void	initPersProjWithDistortion (double px, double py, double u0, double v0, double kud, double kdu)

void	initProjWithKannalaBrandtDistortion (double px, double py, double u0, double v0, const std::vector< double > &distortion_coefficients)

bool	isFovComputed () const

void	computeFov (const unsigned int &w, const unsigned int &h)

double	getHorizontalFovAngle () const

double	getVerticalFovAngle () const

std::vector< vpColVector >	getFovNormals () const

double	get_px () const

double	get_px_inverse () const

double	get_py_inverse () const

double	get_py () const

double	get_u0 () const

double	get_v0 () const

double	get_kud () const

double	get_kdu () const

std::vector< double >	getKannalaBrandtDistortionCoefficients () const

vpCameraParametersProjType	get_projModel () const

vpMatrix	get_K () const

vpMatrix	get_K_inverse () const

void	printParameters ()

Friends
class	vpMeterPixelConversion

class	vpPixelMeterConversion

VISP_EXPORT std::ostream &	operator<< (std::ostream &os, const vpCameraParameters &cam)

void	to_json (nlohmann::json &j, const vpCameraParameters &cam)

void	from_json (const nlohmann::json &j, vpCameraParameters &cam)

Detailed Description

Generic class defining intrinsic camera parameters.

1. Supported camera models

Two camera models are implemented in ViSP.

1.1. Pinhole camera model

In this model [34], a scene view is formed by projecting 3D points into the image plane using a perspective transformation.

$\left[ \begin{array}{c} u \\ v \\ 1 \end{array}\right] = \left[ \begin{array}{ccc} p_x & 0 & u_0 \\ 0 & p_y & v_0 \\ 0 & 0 & 1 \end{array}\right] \left[ \begin{array}{c} x \\ y \\ 1 \end{array}\right]$

where:

are the coordinates of a 3D point in the camera frame
are the coordinates of the projection of the 3D point in the image plane
are the coordinates in pixels of the projected 3D point
are the coordinates of the principal point (the intersection of the optical axes with the image plane) that is usually near the image center
(resp ) is the ratio between the focal length of the lens in meters and the size of the pixel in meters: (resp, being the height of a pixel, ).

When $Z_c \neq 0$ , the previous equation is equivalent to the following:

$\begin{array}{lcl} x &=& X_c / Z_c \\ y &=& Y_c / Z_c \\ u &=& u_0 + x \; p_x \\ v &=& v_0 + y \; p_y \end{array}$

Real lenses usually have some radial distortion. So, the above model is extended as:

$\begin{array}{lcl} x &=& X_c / Z_c \\ y &=& Y_c / Z_c \\ x^{'} &=& x (1 + k_{ud} r^2) \\ y^{'} &=& y (1 + k_{ud} r^2) \\ r^2 &=& x^2 + y^2 \\ u &=& u_0 + x^{'} \; p_x \\ v &=& v_0 + y^{'} \; p_y \end{array}$

where $k_{ud}$ is the first order radial distortion. Higher order distortion coefficients are not considered in ViSP.

Now in ViSP we consider also the inverse transformation, where from pixel coordinates we want to compute their normalized coordinates in the image plane. Previous equations could be written like:

$\begin{array}{lcl} x &=& (u - u_0) / p_x \\ y &=& (v - v_0) / p_y \end{array}$

Considering radial distortion, the above model is extended as:

$\begin{array}{lcl} (u-u_0)^{'} &=& (u-u_0) (1 + k_{du} r^2) \\ (v-v_0)^{'} &=& (v-v_0) (1 + k_{du} r^2) \\ r^2 &=& ((u-u_0)/p_x)^2 + ((v-v_0)/p_y)^2 \\ x &=& (u - u_0)^{'} / p_x \\ y &=& (v - v_0)^{'} / p_y \end{array}$

Finally, in ViSP the main intrinsic camera parameters are $(p_x, p_y)$ the ratio between the focal length and the size of a pixel, and $(u_0, v_0)$ the coordinates of the principal point in pixel. The lens distortion can also be considered by two additional parameters $(k_{ud}, k_{du})$ .

Note: The Tutorial: Camera intrinsic calibration shows how to calibrate a camera to estimate the parameters corresponding to the model implemented in this class.; Note also that Tutorial: Bridge over OpenCV gives the correspondance between ViSP and OpenCV camera modelization.; The conversion from pixel coordinates in the normalized space is implemented in vpPixelMeterConversion, whereas the conversion from normalized coordinates into pixel is implemented in vpMeterPixelConversion.

From a practical point of view, two kinds of camera modelization are implemented in this class:

1.1.1. Camera parameters for a perspective projection without distortion model

In this modelization, only $u_0,v_0,p_x,p_y$ parameters are considered.

Initialization of such a model can be done using:

initPersProjWithoutDistortion() that allows to set parameters;
initFromFov() that computes the parameters from an image size and a camera field of view.

1.1.2. Camera parameters for a perspective projection with distortion model

In this modelization, all the parameters $u_0,v_0,p_x,p_y,k_{ud},k_{du}$ are considered. Initialization of such a model can be done using:

initPersProjWithDistortion() that allows to set $u_0,v_0,p_x,p_y,k_{ud},k_{du}$ parameters;

The selection of the camera model (without or with distortion) is done during vpCameraParameters initialisation.

Here an example of camera initialisation, for a model without distortion. A complete example is given in initPersProjWithoutDistortion().

double px = 600; double py = 600; double u0 = 320; double v0 = 240;
 
// Create a camera parameter container
vpCameraParameters cam;
// Camera initialization with a perspective projection without distortion
// model
cam.initPersProjWithoutDistortion(px,py,u0,v0);
// It is also possible to print the current camera parameters
std::cout << cam << std::endl;

Here an example of camera initialisation, for a model with distortion. A complete example is given in initPersProjWithDistortion().

double px = 600; double py = 600;
double u0 = 320; double v0 = 240;
double kud = -0.19; double kdu = 0.20;
 
// Create a camera parameter container
vpCameraParameters cam;
 
// Camera initialization with a perspective projection without distortion
model cam.initPersProjWithDistortion(px,py,u0,v0,kud,kdu);

The code below shows how to know the currently used projection model:

vpCameraParameters cam;
...
vpCameraParameters::vpCameraParametersProjType projModel;
projModel = cam.get_projModel(); // Get the projection model type

An XML parser for camera parameters is also provided in vpXmlParserCamera.

1.2. Kannala-Brandt camera model

This model [22] deals with fish-eye lenses designed to cover the whole hemispherical field in front of the camera and the angle of view is very large. In this case, the inherent distortion of a fish-eye lens should not be considered only as a derivation from the pinhole model.

The following projection in the general form is adapted:

$\begin{array}{lcl} r(\theta) &=& k_1 \theta + k_2 \theta^3 + k_3 \theta^5 + k_4 \theta^7 + k_5 \theta^9 \end{array}$

where:

$\theta$ is the angle in rad between a point in the real world and the optical axis.
is the distance between the image point and the principal point.

In ViSP, we only consider radially symmetric distortions (caused by fisheye lenses).

2. JSON serialization

Since ViSP 3.6.0, if ViSP is build with JSON for modern C++ 3rd-party we introduce JSON serialization capabilities for vpCameraParameters. The following sample code shows how to save camera parameters in a file named cam.json and reload the parameters from this JSON file.

#include <visp3/core/vpCameraParameters.h>
 
int main()
{
#if defined(VISP_HAVE_NLOHMANN_JSON)
  std::string filename = "cam.json";
  {
    // Save camera parameters in a JSON file
    vpCameraParameters cam(801, 802, 325, 245);
    std::ofstream file(filename);
    const nlohmann::json j = cam;
    file << j;
    file.close();
  }
  {
    // Load camera parameters from a JSON file
    std::ifstream file(filename);
    const nlohmann::json j = nlohmann::json::parse(file);
    vpCameraParameters cam;
    cam = j;
    file.close();
    std::cout << "Read camera parameters from " << filename << ":\n" << cam << std::endl;
  }
#endif
}

If you build and execute the sample code, it will produce the following output:

Read camera parameters from cam.json:
Camera parameters for perspective projection without distortion:
  px = 801   py = 802
  u0 = 325   v0 = 245

The content of the cam.json file is the following:

$ cat cam.json

{"model":"perspectiveWithoutDistortion","px":801.0,"py":802.0,"u0":325.0,"v0":245.0}

Examples: AROgre.cpp, AROgreBasic.cpp, HelloWorldOgre.cpp, HelloWorldOgreAdvanced.cpp, grabRealSense2_T265.cpp, manGeometricFeatures.cpp, manServo4PointsDisplay.cpp, manSimu4Dots.cpp, manSimu4Points.cpp, mbot-apriltag-2D-half-vs.cpp, mbot-apriltag-ibvs.cpp, mbot-apriltag-pbvs.cpp, mbtEdgeKltTracking.cpp, mbtEdgeTracking.cpp, mbtGenericTracking.cpp, mbtGenericTracking2.cpp, mbtGenericTrackingDepth.cpp, mbtGenericTrackingDepthOnly.cpp, mbtKltTracking.cpp, photometricVisualServoing.cpp, photometricVisualServoingWithoutVpServo.cpp, poseVirtualVS.cpp, saveRealSenseData.cpp, servoAfma4Point2DArtVelocity.cpp, servoAfma4Point2DCamVelocity.cpp, servoAfma4Point2DCamVelocityKalman.cpp, servoAfma62DhalfCamVelocity.cpp, servoAfma6AprilTagIBVS.cpp, servoAfma6AprilTagPBVS.cpp, servoAfma6Cylinder2DCamVelocity.cpp, servoAfma6Cylinder2DCamVelocitySecondaryTask.cpp, servoAfma6Ellipse2DCamVelocity.cpp, servoAfma6FourPoints2DArtVelocity.cpp, servoAfma6FourPoints2DCamVelocityLs_cur.cpp, servoAfma6FourPoints2DCamVelocityLs_des.cpp, servoAfma6Line2DCamVelocity.cpp, servoAfma6MegaposePBVS.cpp, servoAfma6Point2DArtVelocity.cpp, servoAfma6Point2DCamVelocity.cpp, servoAfma6Points2DCamVelocityEyeToHand.cpp, servoAfma6Segment2DCamVelocity.cpp, servoAfma6SquareLines2DCamVelocity.cpp, servoAfma6TwoLines2DCamVelocity.cpp, servoBebop2.cpp, servoBiclopsPoint2DArtVelocity.cpp, servoFlirPtuIBVS.cpp, servoFrankaIBVS.cpp, servoFrankaPBVS.cpp, servoMomentImage.cpp, servoMomentPoints.cpp, servoMomentPolygon.cpp, servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, servoPioneerPoint2DDepthWithoutVpServo.cpp, servoPixhawkDroneIBVS.cpp, servoPtu46Point2DArtVelocity.cpp, servoSimu4Points.cpp, servoSimuAfma6FourPoints2DCamVelocity.cpp, servoSimuCircle2DCamVelocityDisplay.cpp, servoSimuCylinder.cpp, servoSimuCylinder2DCamVelocityDisplay.cpp, servoSimuCylinder2DCamVelocityDisplaySecondaryTask.cpp, servoSimuFourPoints2DCamVelocityDisplay.cpp, servoSimuFourPoints2DPolarCamVelocityDisplay.cpp, servoSimuLine2DCamVelocityDisplay.cpp, servoSimuSphere.cpp, servoSimuSphere2DCamVelocityDisplay.cpp, servoSimuSphere2DCamVelocityDisplaySecondaryTask.cpp, servoSimuSquareLine2DCamVelocityDisplay.cpp, servoSimuViper850FourPoints2DCamVelocity.cpp, servoUniversalRobotsIBVS.cpp, servoUniversalRobotsPBVS.cpp, servoViper650FourPoints2DArtVelocityLs_cur.cpp, servoViper650FourPoints2DCamVelocityLs_cur-SR300.cpp, servoViper650FourPoints2DCamVelocityLs_cur.cpp, servoViper650Point2DCamVelocity.cpp, servoViper850FourPoints2DArtVelocityLs_cur.cpp, servoViper850FourPoints2DArtVelocityLs_des.cpp, servoViper850FourPoints2DCamVelocityLs_cur.cpp, servoViper850FourPointsKinect.cpp, servoViper850Point2DArtVelocity-jointAvoidance-basic.cpp, servoViper850Point2DArtVelocity-jointAvoidance-gpa.cpp, servoViper850Point2DArtVelocity-jointAvoidance-large.cpp, servoViper850Point2DArtVelocity.cpp, servoViper850Point2DCamVelocity.cpp, servoViper850Point2DCamVelocityKalman.cpp, simulateCircle2DCamVelocity.cpp, simulateFourPoints2DCartesianCamVelocity.cpp, simulateFourPoints2DPolarCamVelocity.cpp, testAfma6.cpp, testAprilTag.cpp, testDisplays.cpp, testFeatureSegment.cpp, testGenericTracker.cpp, testGenericTrackerDepth.cpp, testImageDraw.cpp, testKeyPoint-2.cpp, testKeyPoint-4.cpp, testMomentAlpha.cpp, testPose.cpp, testRealSense2_D435_align.cpp, testRealSense2_D435_opencv.cpp, testRealSense2_T265_images_odometry.cpp, testRealSense2_T265_images_odometry_async.cpp, testRealSense2_T265_odometry.cpp, testRealSense2_T265_undistort.cpp, testRobotAfma6.cpp, testRobotAfma6Pose.cpp, testRobotViper850.cpp, testRobotViper850Pose.cpp, testTrackDot.cpp, testUndistortImage.cpp, testViper650.cpp, testViper850.cpp, testVirtuoseWithGlove.cpp, trackMeLine.cpp, tutorial-apriltag-detector-live-T265-realsense.cpp, tutorial-apriltag-detector-live-rgbd-realsense.cpp, tutorial-apriltag-detector-live-rgbd-structure-core.cpp, tutorial-apriltag-detector-live.cpp, tutorial-apriltag-detector.cpp, tutorial-bridge-opencv-camera-param.cpp, tutorial-chessboard-pose.cpp, tutorial-detection-object-mbt-deprecated.cpp, tutorial-detection-object-mbt.cpp, tutorial-detection-object-mbt2-deprecated.cpp, tutorial-detection-object-mbt2.cpp, tutorial-draw-frame.cpp, tutorial-flir-ptu-ibvs.cpp, tutorial-franka-acquire-calib-data.cpp, tutorial-homography-from-points.cpp, tutorial-ibvs-4pts-display.cpp, tutorial-ibvs-4pts-image-tracking.cpp, tutorial-ibvs-4pts-ogre-tracking.cpp, tutorial-ibvs-4pts-ogre.cpp, tutorial-ibvs-4pts-wireframe-camera.cpp, tutorial-ibvs-4pts-wireframe-robot-afma6.cpp, tutorial-ibvs-4pts-wireframe-robot-viper.cpp, tutorial-image-simulator.cpp, tutorial-matching-keypoint-homography.cpp, tutorial-mb-edge-tracker.cpp, tutorial-mb-generic-tracker-apriltag-rs2.cpp, tutorial-mb-generic-tracker-apriltag-webcam.cpp, tutorial-mb-generic-tracker-full.cpp, tutorial-mb-generic-tracker-live.cpp, tutorial-mb-generic-tracker-rgbd-blender.cpp, tutorial-mb-generic-tracker-rgbd-realsense-json-settings.cpp, tutorial-mb-generic-tracker-rgbd-realsense.cpp, tutorial-mb-generic-tracker-rgbd-structure-core.cpp, tutorial-mb-generic-tracker-rgbd.cpp, tutorial-mb-generic-tracker-stereo-mono.cpp, tutorial-mb-generic-tracker-stereo.cpp, tutorial-mb-generic-tracker.cpp, tutorial-mb-hybrid-tracker.cpp, tutorial-mb-klt-tracker.cpp, tutorial-mb-tracker-full.cpp, tutorial-mb-tracker.cpp, tutorial-megapose-live-single-object-tracking.cpp, tutorial-pose-from-planar-object.cpp, tutorial-pose-from-points-image.cpp, tutorial-pose-from-points-live.cpp, tutorial-pose-from-points-realsense-T265.cpp, tutorial-pose-from-qrcode-image.cpp, tutorial-undistort.cpp, tutorial-universal-robots-acquire-calib-data.cpp, and wireframeSimulator.cpp.

Definition at line 303 of file vpCameraParameters.h.

Member Enumeration Documentation

◆ vpCameraParametersProjType

enum vpCameraParameters::vpCameraParametersProjType

Enumerator
perspectiveProjWithoutDistortion	Perspective projection without distortion model.
perspectiveProjWithDistortion	Perspective projection with distortion model.
ProjWithKannalaBrandtDistortion	Projection with Kannala-Brandt distortion model.

Definition at line 309 of file vpCameraParameters.h.

Constructor & Destructor Documentation

◆ vpCameraParameters() [1/5]

vpCameraParameters::vpCameraParameters ( )

Default constructor. By default, a perspective projection without distortion model is set.

See also: init()

Definition at line 71 of file vpCameraParameters.cpp.

References init().

◆ vpCameraParameters() [2/5]

vpCameraParameters::vpCameraParameters ( const vpCameraParameters & c )

Copy constructor

Definition at line 83 of file vpCameraParameters.cpp.

References init().

◆ vpCameraParameters() [3/5]

vpCameraParameters::vpCameraParameters	(	double	cam_px,
		double	cam_py,
		double	cam_u0,
		double	cam_v0
	)

Constructor for perspective projection without distortion model

Parameters

cam_px,cam_py	: pixel size
cam_u0,cam_v0	: principal points

Definition at line 99 of file vpCameraParameters.cpp.

References initPersProjWithoutDistortion().

◆ vpCameraParameters() [4/5]

vpCameraParameters::vpCameraParameters	(	double	cam_px,
		double	cam_py,
		double	cam_u0,
		double	cam_v0,
		double	cam_kud,
		double	cam_kdu
	)

Constructor for perspective projection with distortion model

Parameters

cam_px,cam_py	: pixel size
cam_u0,cam_v0	: principal points
cam_kud	: undistorted to distorted radial distortion
cam_kdu	: distorted to undistorted radial distortion

Definition at line 117 of file vpCameraParameters.cpp.

References initPersProjWithDistortion().

◆ vpCameraParameters() [5/5]

vpCameraParameters::vpCameraParameters	(	double	cam_px,
		double	cam_py,
		double	cam_u0,
		double	cam_v0,
		const std::vector< double > &	coefficients
	)

Constructor for projection with Kannala-Brandt distortion model

Parameters

cam_px,cam_py	: pixel size
cam_u0,cam_v0	: principal points
coefficients	: distortion model coefficients

Definition at line 135 of file vpCameraParameters.cpp.

References initProjWithKannalaBrandtDistortion().

◆ ~vpCameraParameters()

vpCameraParameters::~vpCameraParameters ( )

virtual

destructor

nothing much to destroy...

Definition at line 321 of file vpCameraParameters.cpp.

Member Function Documentation

◆ computeFov()

void vpCameraParameters::computeFov	(	const unsigned int &	w,
		const unsigned int &	h
	)

Compute angles and normals of the FOV.

Parameters

w	: Width of the image
h	: Height of the image.

Definition at line 482 of file vpCameraParameters.cpp.

References vpColVector::normalize().

Referenced by vpMbTracker::computeProjectionErrorImpl(), vpMbtFaceDepthNormal::computeROI(), vpMbtFaceDepthDense::computeROI(), vpMbtFaceDepthNormal::displayFeature(), vpMbDepthDenseTracker::getModelForDisplay(), vpMbDepthNormalTracker::getModelForDisplay(), vpMbKltTracker::getModelForDisplay(), vpMbtDistanceLine::getModelForDisplay(), vpMbDepthDenseTracker::init(), vpMbDepthNormalTracker::init(), vpMbEdgeTracker::init(), initFromFov(), vpMbtDistanceLine::initMovingEdge(), vpMbtPolygon::isVisible(), vpMbEdgeKltTracker::postTracking(), vpMbKltTracker::reinit(), vpMbEdgeKltTracker::setPose(), vpMbKltTracker::setPose(), and vpMbtDistanceLine::updateMovingEdge().

◆ get_K()

vpMatrix vpCameraParameters::get_K ( ) const

Return the camera matrix given by:

$K = \left[\begin{array}{ccc} p_x & 0 & u_0 \\ 0 & p_y & v_0 \\ 0 & 0 & 1 \end{array} \right]$

See also: get_K_inverse()

Definition at line 542 of file vpCameraParameters.cpp.

Referenced by vpMbEdgeTracker::downScale(), vpPose::poseFromRectangle(), and vpMbEdgeTracker::upScale().

◆ get_K_inverse()

vpMatrix vpCameraParameters::get_K_inverse ( ) const

Return the inverted camera matrix $K^{-1}$ given by:

$K^{-1} = \left[\begin{array}{ccc} 1/p_x & 0 & -u_0/p_x \\ 0 & 1/p_y & -v_0/p_y \\ 0 & 0 & 1 \end{array} \right]$

See also: get_K()

Definition at line 564 of file vpCameraParameters.cpp.

◆ get_kdu()

double vpCameraParameters::get_kdu ( ) const

inline

Definition at line 408 of file vpCameraParameters.h.

Referenced by vpCalibration::computeStdDeviation_dist().

◆ get_kud()

double vpCameraParameters::get_kud ( ) const

inline

Examples: tutorial-bridge-opencv-camera-param.cpp.

Definition at line 407 of file vpCameraParameters.h.

Referenced by vpCalibration::computeStdDeviation_dist(), vpCalibration::displayGrid(), vpImageTools::initUndistortMap(), and vpImageTools::undistort().

◆ get_projModel()

vpCameraParametersProjType vpCameraParameters::get_projModel ( ) const

inline

Examples: tutorial-megapose-live-single-object-tracking.cpp.

Definition at line 411 of file vpCameraParameters.h.

Referenced by vpImageTools::initUndistortMap().

◆ get_px()

double vpCameraParameters::get_px ( ) const

inline

Examples: mbot-apriltag-2D-half-vs.cpp, servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, servoPioneerPoint2DDepthWithoutVpServo.cpp, testKeyPoint-2.cpp, tutorial-apriltag-detector-live-T265-realsense.cpp, tutorial-bridge-opencv-camera-param.cpp, tutorial-detection-object-mbt2-deprecated.cpp, tutorial-detection-object-mbt2.cpp, and tutorial-matching-keypoint-homography.cpp.

Definition at line 401 of file vpCameraParameters.h.

Referenced by vpFeatureLuminance::buildFrom(), vpHomography::collineation2homography(), vpCalibration::computeCalibration(), vpCalibration::computeCalibrationMulti(), vpMbtDistanceLine::computeInteractionMatrixError(), vpMbtDistanceCylinder::computeInteractionMatrixError(), vpCircle::computeIntersectionPoint(), vpKeyPoint::computePose(), vpCalibration::computeStdDeviation(), vpCalibration::computeStdDeviation_dist(), vpMbEdgeKltTracker::computeVVS(), vpMbEdgeTracker::computeVVSFirstPhase(), vpMbEdgeTracker::computeVVSInit(), vpMbKltTracker::computeVVSInit(), vpMeterPixelConversion::convertEllipse(), vpPixelMeterConversion::convertEllipse(), vpCalibration::displayGrid(), vpMomentObject::fromImage(), vpHomography::homography2collineation(), vpSimulatorAfma6::initDisplay(), vpSimulatorViper850::initDisplay(), vpImageTools::initUndistortMap(), vpSimulatorAfma6::setCameraParameters(), vpSimulatorViper850::setCameraParameters(), vpWireFrameSimulator::setExternalCameraParameters(), vpSimulator::setExternalCameraParameters(), vpWireFrameSimulator::setInternalCameraParameters(), vpSimulator::setInternalCameraParameters(), vpMegaPose::setIntrinsics(), vpImageTools::undistort(), and vpAROgre::updateCameraProjection().

◆ get_px_inverse()

double vpCameraParameters::get_px_inverse ( ) const

inline

Definition at line 402 of file vpCameraParameters.h.

Referenced by vpHomography::collineation2homography(), and vpHomography::homography2collineation().

◆ get_py()

double vpCameraParameters::get_py ( ) const

inline

Examples: servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, servoPioneerPoint2DDepthWithoutVpServo.cpp, testKeyPoint-2.cpp, tutorial-apriltag-detector-live-T265-realsense.cpp, tutorial-bridge-opencv-camera-param.cpp, tutorial-detection-object-mbt2-deprecated.cpp, and tutorial-detection-object-mbt2.cpp.

Definition at line 404 of file vpCameraParameters.h.

Referenced by vpFeatureLuminance::buildFrom(), vpHomography::collineation2homography(), vpCalibration::computeCalibration(), vpCalibration::computeCalibrationMulti(), vpMbtDistanceLine::computeInteractionMatrixError(), vpMbtDistanceCylinder::computeInteractionMatrixError(), vpCircle::computeIntersectionPoint(), vpKeyPoint::computePose(), vpCalibration::computeStdDeviation(), vpCalibration::computeStdDeviation_dist(), vpMeterPixelConversion::convertEllipse(), vpPixelMeterConversion::convertEllipse(), vpCalibration::displayGrid(), vpMomentObject::fromImage(), vpHomography::homography2collineation(), vpSimulatorAfma6::initDisplay(), vpSimulatorViper850::initDisplay(), vpImageTools::initUndistortMap(), vpSimulatorAfma6::setCameraParameters(), vpSimulatorViper850::setCameraParameters(), vpWireFrameSimulator::setExternalCameraParameters(), vpSimulator::setExternalCameraParameters(), vpWireFrameSimulator::setInternalCameraParameters(), vpSimulator::setInternalCameraParameters(), vpMegaPose::setIntrinsics(), vpImageTools::undistort(), and vpAROgre::updateCameraProjection().

◆ get_py_inverse()

double vpCameraParameters::get_py_inverse ( ) const

inline

Definition at line 403 of file vpCameraParameters.h.

Referenced by vpHomography::collineation2homography(), and vpHomography::homography2collineation().

◆ get_u0()

double vpCameraParameters::get_u0 ( ) const

inline

Examples: mbot-apriltag-2D-half-vs.cpp, mbot-apriltag-ibvs.cpp, servoBebop2.cpp, servoPioneerPanSegment3D.cpp, servoPixhawkDroneIBVS.cpp, testKeyPoint-2.cpp, tutorial-apriltag-detector-live-T265-realsense.cpp, tutorial-bridge-opencv-camera-param.cpp, tutorial-detection-object-mbt2-deprecated.cpp, and tutorial-detection-object-mbt2.cpp.

Definition at line 405 of file vpCameraParameters.h.

Referenced by vpHomography::collineation2homography(), vpCalibration::computeCalibration(), vpCalibration::computeCalibrationMulti(), vpMbtDistanceLine::computeInteractionMatrixError(), vpMbtDistanceCylinder::computeInteractionMatrixError(), vpCircle::computeIntersectionPoint(), vpKeyPoint::computePose(), vpCalibration::computeStdDeviation(), vpCalibration::computeStdDeviation_dist(), vpCalibration::displayGrid(), vpHomography::homography2collineation(), vpImageTools::initUndistortMap(), vpMegaPose::setIntrinsics(), vpImageTools::undistort(), and vpAROgre::updateCameraProjection().

◆ get_v0()

double vpCameraParameters::get_v0 ( ) const

inline

Examples: servoBebop2.cpp, servoPixhawkDroneIBVS.cpp, testKeyPoint-2.cpp, tutorial-apriltag-detector-live-T265-realsense.cpp, tutorial-bridge-opencv-camera-param.cpp, tutorial-detection-object-mbt2-deprecated.cpp, and tutorial-detection-object-mbt2.cpp.

Definition at line 406 of file vpCameraParameters.h.

Referenced by vpHomography::collineation2homography(), vpCalibration::computeCalibration(), vpCalibration::computeCalibrationMulti(), vpMbtDistanceLine::computeInteractionMatrixError(), vpMbtDistanceCylinder::computeInteractionMatrixError(), vpCircle::computeIntersectionPoint(), vpKeyPoint::computePose(), vpCalibration::computeStdDeviation(), vpCalibration::computeStdDeviation_dist(), vpCalibration::displayGrid(), vpHomography::homography2collineation(), vpImageTools::initUndistortMap(), vpMegaPose::setIntrinsics(), vpImageTools::undistort(), and vpAROgre::updateCameraProjection().

◆ getFovNormals()

std::vector<vpColVector> vpCameraParameters::getFovNormals ( ) const

inline

Get the list of the normals corresponding to planes describing the field of view.

vector[0] : Left Normal.
vector[1] : Right Normal.
vector[2] : Up Normal.
vector[3] : Down Normal.

See also: computeFov()

Returns: List of the normals.

Definition at line 392 of file vpCameraParameters.h.

References vpTRACE.

Referenced by vpPolygon3D::computePolygonClipped().

◆ getHorizontalFovAngle()

double vpCameraParameters::getHorizontalFovAngle ( ) const

inline

Get the horizontal angle in radian of the field of view.

Returns: FOV horizontal angle computed with px and width.

See also: computeFov(), getVerticalFovAngle()

Definition at line 355 of file vpCameraParameters.h.

References vpTRACE.

◆ getKannalaBrandtDistortionCoefficients()

std::vector<double> vpCameraParameters::getKannalaBrandtDistortionCoefficients ( ) const

inline

Definition at line 409 of file vpCameraParameters.h.

Referenced by vpImageTools::initUndistortMap().

◆ getVerticalFovAngle()

double vpCameraParameters::getVerticalFovAngle ( ) const

inline

Get the vertical angle in radian of the field of view.

Returns: FOV vertical angle computed with py and height.

See also: computeFov(), getHorizontalFovAngle()

Definition at line 371 of file vpCameraParameters.h.

References vpTRACE.

◆ init() [1/2]

void vpCameraParameters::init ( )

basic initialization with the default parameters

Examples: AROgre.cpp, and AROgreBasic.cpp.

Definition at line 148 of file vpCameraParameters.cpp.

References vpException::divideByZeroError.

Referenced by vpCameraParameters().

◆ init() [2/2]

void vpCameraParameters::init ( const vpCameraParameters & c )

initialization from another vpCameraParameters object

Definition at line 326 of file vpCameraParameters.cpp.

◆ initFromCalibrationMatrix()

void vpCameraParameters::initFromCalibrationMatrix ( const vpMatrix & _K )

initialise the camera from a calibration matrix. Using a calibration matrix leads to a camera without distortion

The K matrix in parameters must be like:

$K = \left(\begin{array}{ccc} p_x & 0 & u_0 \\ 0 & p_y & v_0 \\ 0 & 0 & 1 \end{array} \right)$

Parameters

_K	: the 3by3 calibration matrix

Definition at line 342 of file vpCameraParameters.cpp.

References vpException::badValue, vpException::dimensionError, vpArray2D< Type >::getCols(), vpArray2D< Type >::getRows(), and initPersProjWithoutDistortion().

Referenced by vpMbEdgeTracker::downScale(), and vpMbEdgeTracker::upScale().

◆ initFromFov()

void vpCameraParameters::initFromFov	(	const unsigned int &	w,
		const unsigned int &	h,
		const double &	hfov,
		const double &	vfov
	)

Initialize the camera model without distortion from the image dimension and the camera field of view.

Parameters

w	: Image width.
h	: Image height.
hfov	: Camera horizontal field of view angle expressed in radians.
vfov	: Camera vertical field of view angle expressed in radians.

The following sample code shows how to use this function:

#include <visp3/core/vpCameraParameters.h>
#include <visp3/core/vpImage.h>
 
int main()
{
  vpImage<unsigned char> I(480, 640);
  vpCameraParameters cam;
  double hfov = vpMath::rad(56);
  double vfov = vpMath::rad(43);
  cam.initFromFov(I.getWidth(), I.getHeight(), hfov, vfov);
 
  std::cout << cam << std::endl;
  std::cout << "Field of view (horizontal: " << vpMath::deg(cam.getHorizontalFovAngle())
            << " and vertical: " << vpMath::deg(cam.getVerticalFovAngle()) << " degrees)" << std::endl;
}

It produces the following output:

Camera parameters for perspective projection without distortion:
  px = 601.832   py = 609.275
  u0 = 320   v0 = 240
 
Field of view (horizontal: 56 and vertical: 43 degrees)

Definition at line 386 of file vpCameraParameters.cpp.

References computeFov(), and perspectiveProjWithoutDistortion.

◆ initPersProjWithDistortion()

void vpCameraParameters::initPersProjWithDistortion	(	double	cam_px,
		double	cam_py,
		double	cam_u0,
		double	cam_v0,
		double	cam_kud,
		double	cam_kdu
	)

Initialization with specific parameters using perpective projection with distortion model.

Parameters

cam_px,cam_py	: the ratio between the focal length and the size of a pixel.
cam_u0,cam_v0	: principal points coordinates in pixels.
cam_kud	: undistorted to distorted radial distortion.
cam_kdu	: distorted to undistorted radial distortion.

The following sample code shows how to use this function:

#include <visp3/core/vpCameraParameters.h>
#include <visp3/core/vpImage.h>
 
int main()
{
  vpImage<unsigned char> I(480, 640);
  double u0 = I.getWidth()  / 2.;
  double v0 = I.getHeight() / 2.;
  double px = 600;
  double py = 600;
  double kud = -0.19;
  double kdu = 0.20;
  vpCameraParameters cam;
  cam.initPersProjWithDistortion(px, py, u0, v0, kud, kdu);
  cam.computeFov(I.getWidth(), I.getHeight());
  std::cout << cam << std::endl;
  std::cout << "Field of view (horizontal: " << vpMath::deg(cam.getHorizontalFovAngle())
            << " and vertical: " << vpMath::deg(cam.getVerticalFovAngle())
            << " degrees)" << std::endl;
}

It produces the following output:

Camera parameters for perspective projection with distortion:
  px = 600   py = 600
  u0 = 320   v0 = 240
  kud = -0.19
  kdu = 0.2
 
Field of view (horizontal: 56.14497387 and vertical: 43.60281897 degrees)

Examples: testUndistortImage.cpp, and tutorial-undistort.cpp.

Definition at line 262 of file vpCameraParameters.cpp.

References vpException::divideByZeroError, and perspectiveProjWithDistortion.

Referenced by vpRealSense2::getCameraParameters(), vpRealSense::getCameraParameters(), vpAfma6::getCameraParameters(), vpViper650::getCameraParameters(), vpViper850::getCameraParameters(), vpKinect::start(), and vpCameraParameters().

◆ initPersProjWithoutDistortion()

void vpCameraParameters::initPersProjWithoutDistortion	(	double	cam_px,
		double	cam_py,
		double	cam_u0,
		double	cam_v0
	)

Initialization with specific parameters using perpective projection without distortion model.

Parameters

cam_px,cam_py	: the ratio between the focal length and the size of a pixel.
cam_u0,cam_v0	: principal point coordinates in pixels.

The following sample code shows how to use this function:

#include <visp3/core/vpCameraParameters.h>
#include <visp3/core/vpImage.h>
 
int main()
{
  vpImage<unsigned char> I(480, 640);
  double u0 = I.getWidth()  / 2.;
  double v0 = I.getHeight() / 2.;
  double px = 600;
  double py = 600;
  vpCameraParameters cam;
  cam.initPersProjWithoutDistortion(px, py, u0, v0);
  cam.computeFov(I.getWidth(), I.getHeight());
  std::cout << cam << std::endl;
  std::cout << "Field of view (horizontal: " << vpMath::deg(cam.getHorizontalFovAngle())
            << " and vertical: " << vpMath::deg(cam.getVerticalFovAngle())
            << " degrees)" << std::endl;
}

It produces the following output:

Camera parameters for perspective projection without distortion:
  px = 600   py = 600
  u0 = 320   v0 = 240
 
Field of view (horizontal: 56.145 and vertical: 43.6028 degrees)

Examples: mbot-apriltag-2D-half-vs.cpp, mbot-apriltag-ibvs.cpp, mbot-apriltag-pbvs.cpp, mbtEdgeKltTracking.cpp, mbtEdgeTracking.cpp, mbtGenericTracking.cpp, mbtGenericTracking2.cpp, mbtGenericTrackingDepth.cpp, mbtGenericTrackingDepthOnly.cpp, mbtKltTracking.cpp, servoBebop2.cpp, servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, servoPioneerPoint2DDepthWithoutVpServo.cpp, testAprilTag.cpp, testGenericTracker.cpp, testGenericTrackerDepth.cpp, testKeyPoint-2.cpp, testKeyPoint-4.cpp, tutorial-apriltag-detector-live-T265-realsense.cpp, tutorial-apriltag-detector-live.cpp, tutorial-apriltag-detector.cpp, tutorial-detection-object-mbt-deprecated.cpp, tutorial-detection-object-mbt.cpp, tutorial-detection-object-mbt2-deprecated.cpp, tutorial-detection-object-mbt2.cpp, tutorial-draw-frame.cpp, tutorial-mb-edge-tracker.cpp, tutorial-mb-generic-tracker-apriltag-webcam.cpp, tutorial-mb-generic-tracker-full.cpp, tutorial-mb-generic-tracker-live.cpp, tutorial-mb-generic-tracker-stereo-mono.cpp, tutorial-mb-generic-tracker.cpp, tutorial-mb-hybrid-tracker.cpp, tutorial-mb-klt-tracker.cpp, tutorial-mb-tracker-full.cpp, and tutorial-mb-tracker.cpp.

Definition at line 197 of file vpCameraParameters.cpp.

References vpException::divideByZeroError, and perspectiveProjWithoutDistortion.

Referenced by vpRealSense2::getCameraParameters(), vpRealSense::getCameraParameters(), vpSimulatorAfma6::getCameraParameters(), vpSimulatorViper850::getCameraParameters(), vpAfma6::getCameraParameters(), vpViper650::getCameraParameters(), vpViper850::getCameraParameters(), vpServolens::getCameraParameters(), vpSimulatorAfma6::initDisplay(), vpSimulatorViper850::initDisplay(), initFromCalibrationMatrix(), and vpCameraParameters().

◆ initProjWithKannalaBrandtDistortion()

void vpCameraParameters::initProjWithKannalaBrandtDistortion	(	double	cam_px,
		double	cam_py,
		double	cam_u0,
		double	cam_v0,
		const std::vector< double > &	coefficients
	)

Initialization with specific parameters using Kannala-Brandt distortion model

Parameters

cam_px,cam_py	: The ratio between the focal length and the size of a pixel.
cam_u0,cam_v0	: Principal points coordinates in pixels.
coefficients	: Distortion coefficients.

Definition at line 291 of file vpCameraParameters.cpp.

References vpException::divideByZeroError, and ProjWithKannalaBrandtDistortion.

Referenced by vpRealSense2::getCameraParameters(), and vpCameraParameters().

◆ isFovComputed()

bool vpCameraParameters::isFovComputed ( ) const

inline

Specify if the fov has been computed.

See also: computeFov()

Returns: True if the fov has been computed, False otherwise.

Definition at line 344 of file vpCameraParameters.h.

Referenced by vpPolygon3D::computePolygonClipped().

◆ operator!=()

bool vpCameraParameters::operator!= ( const vpCameraParameters & c ) const

False if the two objects are absolutely identical.

Definition at line 474 of file vpCameraParameters.cpp.

◆ operator=()

vpCameraParameters & vpCameraParameters::operator= ( const vpCameraParameters & cam )

copy operator

Definition at line 404 of file vpCameraParameters.cpp.

◆ operator==()

bool vpCameraParameters::operator== ( const vpCameraParameters & c ) const

True if the two objects are absolutely identical.

Definition at line 431 of file vpCameraParameters.cpp.

References vpMath::equal().

◆ printParameters()

void vpCameraParameters::printParameters ( )

Print the camera parameters on the standard output

See also: operator<<(std::ostream &, const vpCameraParameters &)

Examples: servoBebop2.cpp, servoPixhawkDroneIBVS.cpp, servoViper850FourPoints2DArtVelocityLs_cur.cpp, servoViper850FourPoints2DArtVelocityLs_des.cpp, servoViper850FourPoints2DCamVelocityLs_cur.cpp, and servoViper850FourPointsKinect.cpp.

Definition at line 581 of file vpCameraParameters.cpp.

References perspectiveProjWithDistortion, perspectiveProjWithoutDistortion, and ProjWithKannalaBrandtDistortion.

Referenced by vpCalibration::computeCalibration(), and vpCalibration::computeCalibrationMulti().

Friends And Related Function Documentation

◆ from_json

void from_json	(	const nlohmann::json &	j,
		vpCameraParameters &	cam
	)

friend

Deserialize a JSON object into camera parameters. The minimal required properties are:

Pixel size: px, py
Principal point: u0, v0

If a projection model (vpCameraParameters::vpCameraParametersProjType) is supplied, then other parameters may be expected:

In the case of perspective projection with distortion, ku, and kud must be supplied.
In the case of Kannala-Brandt distortion, the list of coefficients must be supplied.

An example of a JSON object representing a camera is:

{
  "px": 300.0,
  "py": 300.0,
  "u0": 120.5,
  "v0": 115.0,
  "model": "perspectiveWithDistortion", // one of ["perspectiveWithoutDistortion", "perspectiveWithDistortion", "kannalaBrandtDistortion"]. If ommitted, camera is assumed to have no distortion
  "kud": 0.5, // required since "model" == perspectiveWithDistortion
  "kdu": 0.5
}

Parameters

j	The json object to deserialize.
cam	The modified camera.

Definition at line 517 of file vpCameraParameters.h.

◆ operator<<

VISP_EXPORT std::ostream& operator<<	(	std::ostream &	os,
		const vpCameraParameters &	cam
	)

friend

Print on the output stream os the camera parameters.

Parameters

os	: Output stream.
cam	: Camera parameters.

Definition at line 616 of file vpCameraParameters.cpp.

◆ to_json

void to_json	(	nlohmann::json &	j,
		const vpCameraParameters &	cam
	)

friend

Converts camera parameters into a JSON representation.

See also: from_json for more information on the content

Parameters

j	the resulting JSON object
cam	the camera to serialize

Definition at line 464 of file vpCameraParameters.h.

◆ vpMeterPixelConversion

friend class vpMeterPixelConversion

friend

Definition at line 305 of file vpCameraParameters.h.

◆ vpPixelMeterConversion

friend class vpPixelMeterConversion

friend

Definition at line 306 of file vpCameraParameters.h.

Public Types

Public Member Functions

Friends

Detailed Description

Member Enumeration Documentation

◆ vpCameraParametersProjType

Constructor & Destructor Documentation

◆ vpCameraParameters() [1/5]

◆ vpCameraParameters() [2/5]

◆ vpCameraParameters() [3/5]

◆ vpCameraParameters() [4/5]

◆ vpCameraParameters() [5/5]

◆ ~vpCameraParameters()

Member Function Documentation

◆ computeFov()

◆ get_K()

◆ get_K_inverse()

◆ get_kdu()

◆ get_kud()

◆ get_projModel()

◆ get_px()

◆ get_px_inverse()

◆ get_py()

◆ get_py_inverse()

◆ get_u0()

◆ get_v0()

◆ getFovNormals()

◆ getHorizontalFovAngle()

◆ getKannalaBrandtDistortionCoefficients()

◆ getVerticalFovAngle()

◆ init() [1/2]

◆ init() [2/2]

◆ initFromCalibrationMatrix()

◆ initFromFov()

◆ initPersProjWithDistortion()

◆ initPersProjWithoutDistortion()

◆ initProjWithKannalaBrandtDistortion()

◆ isFovComputed()

◆ operator!=()

◆ operator=()

◆ operator==()

◆ printParameters()

Friends And Related Function Documentation

◆ from_json

◆ operator<<

◆ to_json

◆ vpMeterPixelConversion

◆ vpPixelMeterConversion