Visual Servoing Platform  version 3.6.1 under development (2024-05-26)

Servo a sphere:

* ViSP, open source Visual Servoing Platform software.
* Copyright (C) 2005 - 2023 by Inria. All rights reserved.
* This software is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* See the file LICENSE.txt at the root directory of this source
* distribution for additional information about the GNU GPL.
* For using ViSP with software that can not be combined with the GNU
* GPL, please contact Inria about acquiring a ViSP Professional
* Edition License.
* See for more information.
* This software was developed at:
* Inria Rennes - Bretagne Atlantique
* Campus Universitaire de Beaulieu
* 35042 Rennes Cedex
* France
* If you have questions regarding the use of this file, please contact
* Inria at
* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* Description:
* Simulation of a 2D visual servoing on a sphere.
#include <stdio.h>
#include <stdlib.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpMath.h>
#include <visp3/core/vpSphere.h>
#include <visp3/gui/vpDisplayD3D.h>
#include <visp3/gui/vpDisplayGDI.h>
#include <visp3/gui/vpDisplayGTK.h>
#include <visp3/gui/vpDisplayOpenCV.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/gui/vpProjectionDisplay.h>
#include <visp3/io/vpParseArgv.h>
#include <visp3/robot/vpSimulatorCamera.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/visual_features/vpFeatureEllipse.h>
#include <visp3/vs/vpServo.h>
#include <visp3/vs/vpServoDisplay.h>
// List of allowed command line options
#define GETOPTARGS "cdho"
void usage(const char *name, const char *badparam);
bool getOptions(int argc, const char **argv, bool &click_allowed, bool &display);
void usage(const char *name, const char *badparam)
fprintf(stdout, "\n\
Simulation of a 2D visual servoing on a sphere:\n\
- eye-in-hand control law,\n\
- velocity computed in the camera frame,\n\
- display the camera view,\n\
- a secondary task is the added.\n\
%s [-c] [-d] [-o] [-h]\n",
fprintf(stdout, "\n\
OPTIONS: Default\n\
Disable the mouse click. Useful to automate the \n\
execution of this program without human intervention.\n\
-d \n\
Turn off the display.\n\
-o \n\
Disable new projection operator usage for secondary task.\n\
Print the help.\n");
if (badparam)
fprintf(stdout, "\nERROR: Bad parameter [%s]\n", badparam);
bool getOptions(int argc, const char **argv, bool &click_allowed, bool &display, bool &new_proj_operator)
const char *optarg_;
int c;
while ((c = vpParseArgv::parse(argc, argv, GETOPTARGS, &optarg_)) > 1) {
switch (c) {
case 'c':
click_allowed = false;
case 'd':
display = false;
case 'o':
new_proj_operator = false;
case 'h':
usage(argv[0], nullptr);
return false;
usage(argv[0], optarg_);
return false;
if ((c == 1) || (c == -1)) {
// standalone param or error
usage(argv[0], nullptr);
std::cerr << "ERROR: " << std::endl;
std::cerr << " Bad argument " << optarg_ << std::endl << std::endl;
return false;
return true;
int main(int argc, const char **argv)
#if (defined(VISP_HAVE_LAPACK) || defined(VISP_HAVE_EIGEN3) || defined(VISP_HAVE_OPENCV))
try {
bool opt_display = true;
bool opt_click_allowed = true;
bool opt_new_proj_operator = true;
// Read the command line options
if (getOptions(argc, argv, opt_click_allowed, opt_display, opt_new_proj_operator) == false) {
return (EXIT_FAILURE);
vpImage<unsigned char> I(512, 512, 0);
vpImage<unsigned char> Iext(512, 512, 0);
// We open a window if a display is available
#if defined(VISP_HAVE_X11)
vpDisplayX displayI;
vpDisplayX displayExt;
#elif defined(VISP_HAVE_GTK)
vpDisplayGTK displayI;
vpDisplayGTK displayExt;
#elif defined(VISP_HAVE_GDI)
vpDisplayGDI displayI;
vpDisplayGDI displayExt;
#elif defined(HAVE_OPENCV_HIGHGUI)
vpDisplayOpenCV displayI;
vpDisplayOpenCV displayExt;
#elif defined(VISP_HAVE_D3D9)
vpDisplayD3D displayI;
vpDisplayD3D displayExt;
if (opt_display) {
#if defined(VISP_HAVE_X11) || defined(VISP_HAVE_GTK) || defined(VISP_HAVE_GDI) || defined(VISP_HAVE_OPENCV)
// Display size is automatically defined by the image (I) size
displayI.init(I, 100, 100, "Camera view...");
displayExt.init(Iext, 130 + static_cast<int>(I.getWidth()), 100, "External view");
// Display the image
// The image class has a member that specify a pointer toward
// the display that has been initialized in the display declaration
// therefore is is no longer necessary to make a reference to the
// display variable.
vpProjectionDisplay externalview;
double px = 600, py = 600;
double u0 = I.getWidth() / 2., v0 = I.getHeight() / 2.;
vpCameraParameters cam(px, py, u0, v0);
vpServo task;
// sets the initial camera location
cMo[0][3] = 0.1;
cMo[1][3] = 0.2;
cMo[2][3] = 2;
// Compute the position of the object in the world frame
wMo = wMc * cMo;
cMod[0][3] = 0;
cMod[1][3] = 0;
cMod[2][3] = 1;
// sets the sphere coordinates in the world frame
vpSphere sphere;
sphere.setWorldCoordinates(0, 0, 0, 0.1);
// sets the desired position of the visual feature
// computes the sphere coordinates in the camera frame and its 2D
// coordinates sets the current position of the visual feature
// define the task
// - we want an eye-in-hand control law
// - robot is controlled in the camera frame
// we want to see a sphere on a sphere
std::cout << std::endl;
task.addFeature(p, pd);
// set the gain
// Set the point of view of the external view
vpHomogeneousMatrix cextMo(0, 0, 4, vpMath::rad(40), vpMath::rad(10), vpMath::rad(60));
// Display the initial scene
vpServoDisplay::display(task, cam, I);
externalview.display(Iext, cextMo, cMo, cam, vpColor::red);
// Display task information
if (opt_display && opt_click_allowed) {
vpDisplay::displayText(I, 20, 20, "Click to start visual servo...", vpColor::white);
unsigned int iter = 0;
bool stop = false;
bool start_secondary_task = false;
// loop
while (iter++ < 2000 && !stop) {
std::cout << "---------------------------------------------" << iter << std::endl;
// get the robot position
// Compute the position of the object frame in the camera frame
cMo = wMc.inverse() * wMo;
// new sphere position: retrieve x,y and Z of the vpSphere structure
if (opt_display) {
vpServoDisplay::display(task, cam, I);
externalview.display(Iext, cextMo, cMo, cam, vpColor::red);
// compute the control law
// Wait primary task convergence before considering secondary task
if (task.getError().sumSquare() < 1e-6) {
start_secondary_task = true;
if (start_secondary_task) {
// Only 3 dof are required to achieve primary task: vz, wx, wy
// It remains 3 free dof (vx, vy, wz) that could be used in a secondary task for example to move around the
// sphere
vpColVector de2dt(6);
de2dt[0] = 0.50; // vx = 0.50 m/s should also generate a motion on wy = (I-WpW)de2dt[4]
de2dt[1] = 0.25; // vy = 0.25 m/s should generate a motion on wx = (I-WpW)de2dt[3]
de2dt[2] = 1; // vz = 1 m/s should be zero in vz = (I-WpW)de2dt[2]
de2dt[5] = vpMath::rad(10); // wz = 10 rad/s should generate a motion on (I-WpW)de2dt[5]
std::cout << "de2dt :" << de2dt.t() << std::endl;
vpColVector sec = task.secondaryTask(de2dt, opt_new_proj_operator);
std::cout << "(I-WpW)de2dt :" << sec.t() << std::endl;
v += sec;
if (opt_display && opt_click_allowed) {
std::stringstream ss;
ss << std::string("New projection operator: ") +
(opt_new_proj_operator ? std::string("yes (use option -o to use old one)") : std::string("no"));
vpDisplay::displayText(I, 20, 20, "Secondary task enabled: yes", vpColor::white);
vpDisplay::displayText(I, 40, 20, ss.str(), vpColor::white);
} else {
if (opt_display && opt_click_allowed) {
vpDisplay::displayText(I, 20, 20, "Secondary task enabled: no", vpColor::white);
// send the camera velocity to the controller
std::cout << "|| s - s* || = " << (task.getError()).sumSquare() << std::endl;
if (opt_display) {
vpDisplay::displayText(I, 60, 20, "Click to stop visual servo...", vpColor::white);
if (vpDisplay::getClick(I, false)) {
stop = true;
if (opt_display && opt_click_allowed) {
vpServoDisplay::display(task, cam, I);
vpDisplay::displayText(I, 20, 20, "Click to quit...", vpColor::white);
// Display task information
} catch (const vpException &e) {
std::cout << "Catch a ViSP exception: " << e << std::endl;
std::cout << "Cannot run this example: install Lapack, Eigen3 or OpenCV" << std::endl;
Generic class defining intrinsic camera parameters.
Implementation of column vector and the associated operations.
Definition: vpColVector.h:163
double sumSquare() const
vpRowVector t() const
static const vpColor white
Definition: vpColor.h:206
static const vpColor red
Definition: vpColor.h:211
Display for windows using Direct3D 3rd party. Thus to enable this class Direct3D should be installed....
Definition: vpDisplayD3D.h:101
Display for windows using GDI (available on any windows 32 platform).
Definition: vpDisplayGDI.h:128
The vpDisplayGTK allows to display image using the GTK 3rd party library. Thus to enable this class G...
Definition: vpDisplayGTK.h:128
The vpDisplayOpenCV allows to display image using the OpenCV library. Thus to enable this class OpenC...
Use the X11 console to display images on unix-like OS. Thus to enable this class X11 should be instal...
Definition: vpDisplayX.h:128
void init(vpImage< unsigned char > &I, int win_x=-1, int win_y=-1, const std::string &win_title="") vp_override
static bool getClick(const vpImage< unsigned char > &I, bool blocking=true)
static void display(const vpImage< unsigned char > &I)
static void flush(const vpImage< unsigned char > &I)
static void displayText(const vpImage< unsigned char > &I, const vpImagePoint &ip, const std::string &s, const vpColor &color)
error that can be emitted by ViSP classes.
Definition: vpException.h:59
static void create(vpFeaturePoint &s, const vpCameraParameters &cam, const vpDot &d)
Class that defines 2D ellipse visual feature.
void track(const vpHomogeneousMatrix &cMo)
Implementation of an homogeneous matrix and operations on such kind of matrices.
vpHomogeneousMatrix inverse() const
unsigned int getWidth() const
Definition: vpImage.h:245
unsigned int getHeight() const
Definition: vpImage.h:184
static double rad(double deg)
Definition: vpMath.h:127
static bool parse(int *argcPtr, const char **argv, vpArgvInfo *argTable, int flags)
Definition: vpParseArgv.cpp:69
interface with the image for feature display
void display(vpImage< unsigned char > &I, const vpHomogeneousMatrix &cextMo, const vpHomogeneousMatrix &cMo, const vpCameraParameters &cam, const vpColor &color, const bool &displayTraj=false, unsigned int thickness=1)
void insert(vpForwardProjection &fp)
void setVelocity(const vpRobot::vpControlFrameType frame, const vpColVector &vel) vp_override
Definition: vpRobot.h:82
static void display(const vpServo &s, const vpCameraParameters &cam, const vpImage< unsigned char > &I, vpColor currentColor=vpColor::green, vpColor desiredColor=vpColor::red, unsigned int thickness=1)
Definition: vpServo.h:155
void addFeature(vpBasicFeature &s_cur, vpBasicFeature &s_star, unsigned int select=vpBasicFeature::FEATURE_ALL)
Definition: vpServo.cpp:329
void print(const vpServo::vpServoPrintType display_level=ALL, std::ostream &os=std::cout)
Definition: vpServo.cpp:169
void setLambda(double c)
Definition: vpServo.h:976
vpColVector secondaryTask(const vpColVector &de2dt, const bool &useLargeProjectionOperator=false)
Definition: vpServo.cpp:1087
void setServo(const vpServoType &servo_type)
Definition: vpServo.cpp:132
vpColVector getError() const
Definition: vpServo.h:504
vpColVector computeControlLaw()
Definition: vpServo.cpp:703
Class that defines the simplest robot: a free flying camera.
Class that defines a 3D sphere in the object frame and allows forward projection of a 3D sphere in th...
Definition: vpSphere.h:78
void setWorldCoordinates(const vpColVector &oP) vp_override
Definition: vpSphere.cpp:59
void display(vpImage< unsigned char > &I, const std::string &title)
Display a gray-scale image.