Visual Servoing Platform version 3.7.0
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vpCameraParameters Class Reference
core: Core module » Camera model

#include <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 [36], 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:

  • $(X_c,Y_c,Z_c)$ are the coordinates of a 3D point in the camera frame
  • $(x,y)$ are the coordinates of the projection of the 3D point in the image plane
  • $(u,v)$ are the coordinates in pixels of the projected 3D point
  • $(u_0,v_0)$ are the coordinates of the principal point (the intersection of the optical axes with the image plane) that is usually near the image center
  • $p_x$ (resp $p_y$) is the ratio between the focal length of the lens $f$ in meters and the size of the pixel $l_x$ in meters: $p_x=f/l_x$ (resp, $l_y$ being the height of a pixel, $p_y=f/l_y$).

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 correspondence between ViSP and OpenCV camera modelization.
The conversion from pixel coordinates $(u,v)$ in the normalized space $(x,y)$ 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:

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:

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 [23] 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.
  • $r$ 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>
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
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
}
vpCameraParameters
Generic class defining intrinsic camera parameters.
Definition vpCameraParameters.h:311
VISP_NAMESPACE_NAME
Definition vpEigenConversion.h:44

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, catchAprilTag.cpp, catchArUco.cpp, catchGenericTrackerDeterminist.cpp, catchJsonCamera.cpp, catchPanda.cpp, catchRBT.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, perfApriltagDetection.cpp, perfGenericTracker.cpp, photometricMappingVisualServoing.cpp, photometricVisualServoing.cpp, photometricVisualServoingWithoutVpServo.cpp, poseVirtualVS.cpp, servoAfma62DhalfCamVelocity.cpp, servoAfma6AprilTagIBVS.cpp, servoAfma6AprilTagPBVS.cpp, servoAfma6Cylinder2DCamVelocity.cpp, servoAfma6Cylinder2DCamVelocitySecondaryTask.cpp, servoAfma6Ellipse2DCamVelocity.cpp, servoAfma6FourPoints2DArtVelocity.cpp, servoAfma6FourPoints2DCamVelocityLs_cur.cpp, servoAfma6FourPoints2DCamVelocityLs_cur_integrator.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-EyeToHand-Lcur_cVe_eJe.cpp, servoFrankaIBVS-EyeToHand-Lcur_cVf_fVe_eJe.cpp, servoFrankaIBVS-EyeToHand-Ldes_cVf_fVe_eJe.cpp, servoFrankaIBVS.cpp, servoFrankaPBVS.cpp, servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, servoPioneerPoint2DDepthWithoutVpServo.cpp, servoPixhawkDroneIBVS.cpp, servoPololuPtuPoint2DJointVelocity.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, testCameraParametersConversion.cpp, testDisplays.cpp, testFeatureSegment.cpp, testGenericTracker.cpp, testGenericTrackerDepth.cpp, testImageDraw.cpp, testKeyPoint-2.cpp, testKeyPoint-4.cpp, testMbtXmlGenericParser.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, testXmlParserCamera.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-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-grabber-realsense.cpp, tutorial-homography-from-points.cpp, tutorial-hsv-segmentation-pcl-viewer.cpp, tutorial-hsv-segmentation-pcl.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-read.cpp, tutorial-mb-generic-tracker-rgbd-blender.cpp, tutorial-mb-generic-tracker-rgbd-realsense-json.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-save.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-panda3d-renderer.cpp, tutorial-pf.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-rbt-realsense.cpp, tutorial-rbt-sequence.cpp, tutorial-ukf.cpp, tutorial-undistort.cpp, visp-acquire-franka-calib-data.cpp, visp-acquire-universal-robots-calib-data.cpp, visp-calibrate-camera.cpp, visp-compute-apriltag-poses.cpp, visp-compute-chessboard-poses.cpp, visp-save-rs-dataset.cpp, and wireframeSimulator.cpp.

Definition at line 310 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.

Examples
servoAfma62DhalfCamVelocity.cpp, servoAfma6AprilTagIBVS.cpp, servoAfma6AprilTagPBVS.cpp, servoAfma6Cylinder2DCamVelocity.cpp, servoAfma6Cylinder2DCamVelocitySecondaryTask.cpp, servoAfma6FourPoints2DArtVelocity.cpp, servoAfma6FourPoints2DCamVelocityLs_cur.cpp, servoAfma6FourPoints2DCamVelocityLs_cur_integrator.cpp, servoAfma6FourPoints2DCamVelocityLs_des.cpp, servoAfma6Line2DCamVelocity.cpp, servoBebop2.cpp, servoViper650FourPoints2DArtVelocityLs_cur.cpp, servoViper650FourPoints2DCamVelocityLs_cur.cpp, servoViper850FourPoints2DArtVelocityLs_cur.cpp, servoViper850FourPoints2DArtVelocityLs_des.cpp, servoViper850FourPoints2DCamVelocityLs_cur.cpp, servoViper850FourPointsKinect.cpp, and tutorial-undistort.cpp.

Definition at line 316 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 67 of file vpCameraParameters.cpp.

References init().

Referenced by from_json, init(), operator!=(), operator<<, operator=(), operator==(), to_json, and vpCameraParameters().

◆ vpCameraParameters() [2/5]

vpCameraParameters::vpCameraParameters ( const vpCameraParameters & c)

Copy constructor

Definition at line 79 of file vpCameraParameters.cpp.

References init(), and vpCameraParameters().

◆ 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: Pixel size along x axis (horizontal).
cam_py: Pixel size along y axis (vertical)
cam_u0: Principal point coordinate in pixel along x.
cam_v0: Principal point coordinate in pixel along y.

Definition at line 96 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: Pixel size along x axis (horizontal).
cam_py: Pixel size along y axis (vertical)
cam_u0: Principal point coordinate in pixel along x.
cam_v0: Principal point coordinate in pixel along y.
cam_kud: Undistorted to distorted radial distortion.
cam_kdu: Distorted to undistorted radial distortion.

Definition at line 115 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: Pixel size along x axis (horizontal).
cam_py: Pixel size along y axis (vertical)
cam_u0: Principal point coordinate in pixel along x.
cam_v0: Principal point coordinate in pixel along y.
coefficients: distortion model coefficients

Definition at line 134 of file vpCameraParameters.cpp.

References initProjWithKannalaBrandtDistortion().

◆ ~vpCameraParameters()

vpCameraParameters::~vpCameraParameters ( )
virtual

Destructor that does nothing.

Definition at line 334 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.
Examples
testCameraParametersConversion.cpp.

Definition at line 524 of file vpCameraParameters.cpp.

References vpColVector::normalize().

Referenced by vpMbtFaceDepthNormal::displayFeature(), vpMbtFaceDepthNormal::displayFeature(), vpMbDepthDenseTracker::getModelForDisplay(), vpMbDepthNormalTracker::getModelForDisplay(), vpMbKltTracker::getModelForDisplay(), vpMbtDistanceLine::getModelForDisplay(), initFromFov(), and vpMbtPolygon::isVisible().

◆ get_K()

vpMatrix vpCameraParameters::get_K ( ) const

Return the camera matrix $K$ 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 591 of file vpCameraParameters.cpp.

◆ 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 616 of file vpCameraParameters.cpp.

◆ get_kdu()

double vpCameraParameters::get_kdu ( ) const
inline

Definition at line 412 of file vpCameraParameters.h.

Referenced by vpCalibration::computeStdDeviation_dist().

◆ get_kud()

double vpCameraParameters::get_kud ( ) const
inline

Definition at line 411 of file vpCameraParameters.h.

Referenced by vpCalibration::computeStdDeviation_dist().

◆ get_projModel()

vpCameraParametersProjType vpCameraParameters::get_projModel ( ) const
inline

Definition at line 415 of file vpCameraParameters.h.

◆ get_px()

double vpCameraParameters::get_px ( ) const
inline
Examples
tutorial-apriltag-detector-live-T265-realsense.cpp, and visp-calibrate-camera.cpp.

Definition at line 405 of file vpCameraParameters.h.

Referenced by vpCalibration::computeCalibration(), vpCalibration::computeCalibrationMulti(), vpCalibration::computeStdDeviation(), vpCalibration::computeStdDeviation_dist(), vpRBSilhouetteMeTracker::computeVVSIter(), vpRBSilhouetteMeTracker::extractFeatures(), vpSimulatorAfma6::initDisplay(), vpSimulatorViper850::initDisplay(), vpSimulator::setExternalCameraParameters(), and vpSimulator::setInternalCameraParameters().

◆ get_px_inverse()

double vpCameraParameters::get_px_inverse ( ) const
inline

Definition at line 406 of file vpCameraParameters.h.

◆ get_py()

double vpCameraParameters::get_py ( ) const
inline
Examples
tutorial-apriltag-detector-live-T265-realsense.cpp, and visp-calibrate-camera.cpp.

Definition at line 408 of file vpCameraParameters.h.

Referenced by vpCalibration::computeCalibration(), vpCalibration::computeCalibrationMulti(), vpCalibration::computeStdDeviation(), vpCalibration::computeStdDeviation_dist(), vpSimulatorAfma6::initDisplay(), vpSimulatorViper850::initDisplay(), vpSimulator::setExternalCameraParameters(), and vpSimulator::setInternalCameraParameters().

◆ get_py_inverse()

double vpCameraParameters::get_py_inverse ( ) const
inline

Definition at line 407 of file vpCameraParameters.h.

◆ get_u0()

double vpCameraParameters::get_u0 ( ) const
inline
Examples
tutorial-apriltag-detector-live-T265-realsense.cpp.

Definition at line 409 of file vpCameraParameters.h.

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

◆ get_v0()

double vpCameraParameters::get_v0 ( ) const
inline
Examples
tutorial-apriltag-detector-live-T265-realsense.cpp.

Definition at line 410 of file vpCameraParameters.h.

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

◆ 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 397 of file vpCameraParameters.h.

◆ 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 362 of file vpCameraParameters.h.

◆ getKannalaBrandtDistortionCoefficients()

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

Definition at line 413 of file vpCameraParameters.h.

◆ 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 377 of file vpCameraParameters.h.

◆ init() [1/2]

void vpCameraParameters::init ( )

Basic initialization with the default parameters.

Examples
AROgre.cpp, and AROgreBasic.cpp.

Definition at line 147 of file vpCameraParameters.cpp.

References vpException::divideByZeroError.

Referenced by vpCameraParameters(), and vpCameraParameters().

◆ init() [2/2]

void vpCameraParameters::init ( const vpCameraParameters & c)

Initialization from another vpCameraParameters object.

Definition at line 339 of file vpCameraParameters.cpp.

References vpCameraParameters().

◆ 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 3-by-3 calibration matrix

Definition at line 355 of file vpCameraParameters.cpp.

References vpException::badValue, vpException::dimensionError, and initPersProjWithoutDistortion().

◆ 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>
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
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;
}
vpImage
Definition of the vpImage class member functions.
Definition vpImage.h:131
vpMath::rad
static double rad(double deg)
Definition vpMath.h:129
vpMath::deg
static double deg(double rad)
Definition vpMath.h:119

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 409 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 perspective projection with distortion model.

Parameters
cam_px: Pixel size along x axis (horizontal).
cam_py: Pixel size along y axis (vertical)
cam_u0: Principal point coordinate in pixel along x.
cam_v0: Principal point coordinate in pixel along y.
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>
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
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
catchJsonCamera.cpp, testCameraParametersConversion.cpp, and testXmlParserCamera.cpp.

Definition at line 274 of file vpCameraParameters.cpp.

References vpException::divideByZeroError, and perspectiveProjWithDistortion.

Referenced by vpCameraParameters().

◆ initPersProjWithoutDistortion()

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

Initialization with specific parameters using perspective projection without distortion model.

Parameters
cam_px: Pixel size along x axis (horizontal).
cam_py: Pixel size along y axis (vertical)
cam_u0: Principal point coordinate in pixel along x.
cam_v0: Principal point coordinate in pixel along y.

The following sample code shows how to use this function:

#include <visp3/core/vpCameraParameters.h>
#include <visp3/core/vpImage.h>
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
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
catchJsonCamera.cpp, mbtGenericTracking.cpp, mbtGenericTrackingDepth.cpp, testCameraParametersConversion.cpp, testKeyPoint-2.cpp, testMbtXmlGenericParser.cpp, testXmlParserCamera.cpp, tutorial-apriltag-detector-live-T265-realsense.cpp, tutorial-detection-object-mbt2-deprecated.cpp, tutorial-detection-object-mbt2.cpp, and visp-calibrate-camera.cpp.

Definition at line 202 of file vpCameraParameters.cpp.

References vpException::divideByZeroError, and perspectiveProjWithoutDistortion.

Referenced by 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: Pixel size along x axis (horizontal).
cam_py: Pixel size along y axis (vertical)
cam_u0: Principal point coordinate in pixel along x.
cam_v0: Principal point coordinate in pixel along y.
coefficients: Distortion coefficients.
Examples
catchJsonCamera.cpp, and testXmlParserCamera.cpp.

Definition at line 306 of file vpCameraParameters.cpp.

References vpException::divideByZeroError, and ProjWithKannalaBrandtDistortion.

Referenced by 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 351 of file vpCameraParameters.h.

◆ operator!=()

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

False if the two objects are absolutely identical.

Definition at line 516 of file vpCameraParameters.cpp.

References vpCameraParameters().

◆ operator=()

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

Copy operator.

Definition at line 427 of file vpCameraParameters.cpp.

References vpCameraParameters().

◆ operator==()

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

True if the two objects are absolutely identical.

Definition at line 454 of file vpCameraParameters.cpp.

References vpMath::equal(), and vpCameraParameters().

◆ printParameters()

void vpCameraParameters::printParameters ( )

Print the camera parameters on the standard output.

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

Definition at line 637 of file vpCameraParameters.cpp.

References vpException::fatalError, perspectiveProjWithDistortion, perspectiveProjWithoutDistortion, ProjWithKannalaBrandtDistortion, and vpArray2D< Type >::size().

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

◆ 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 omitted, camera is assumed to have no distortion
"kud": 0.5, // required since "model" == perspectiveWithDistortion
"kdu": 0.5
}
Parameters
jThe json object to deserialize.
camThe modified camera.

Definition at line 534 of file vpCameraParameters.h.

References vpException::fatalError, from_json, perspectiveProjWithDistortion, perspectiveProjWithoutDistortion, ProjWithKannalaBrandtDistortion, and vpCameraParameters().

Referenced by from_json.

◆ 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 682 of file vpCameraParameters.cpp.

References vpException::fatalError, operator<<, perspectiveProjWithDistortion, perspectiveProjWithoutDistortion, ProjWithKannalaBrandtDistortion, and vpCameraParameters().

Referenced by operator<<.

◆ 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
jThe resulting JSON object.
camThe camera to serialize.

Definition at line 480 of file vpCameraParameters.h.

References vpException::fatalError, perspectiveProjWithDistortion, perspectiveProjWithoutDistortion, ProjWithKannalaBrandtDistortion, to_json, and vpCameraParameters().

Referenced by to_json.

◆ vpMeterPixelConversion

friend class vpMeterPixelConversion
friend

Definition at line 312 of file vpCameraParameters.h.

References vpMeterPixelConversion.

Referenced by vpMeterPixelConversion.

◆ vpPixelMeterConversion

friend class vpPixelMeterConversion
friend

Definition at line 313 of file vpCameraParameters.h.

References vpPixelMeterConversion.

Referenced by vpPixelMeterConversion.