servoSimuSphere.cpp

/*
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2025 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 https://visp.inria.fr 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 visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * Demonstration of the wireframe simulator with a simple visual servoing
 */

 
#include <cmath>  // std::fabs
#include <limits> // numeric_limits
#include <stdlib.h>
 
#include <visp3/core/vpCameraParameters.h>
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpImage.h>
#include <visp3/core/vpIoTools.h>
#include <visp3/core/vpMath.h>
#include <visp3/core/vpSphere.h>
#include <visp3/core/vpTime.h>
#include <visp3/core/vpVelocityTwistMatrix.h>
#include <visp3/gui/vpDisplayFactory.h>
#include <visp3/gui/vpPlot.h>
#include <visp3/io/vpImageIo.h>
#include <visp3/io/vpParseArgv.h>
#include <visp3/robot/vpSimulatorCamera.h>
#include <visp3/robot/vpWireFrameSimulator.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/visual_features/vpGenericFeature.h>
#include <visp3/vs/vpServo.h>
 
#define GETOPTARGS "dhp"
 
#if defined(VISP_HAVE_DISPLAY) && (defined(VISP_HAVE_LAPACK) || defined(VISP_HAVE_EIGEN3) || defined(VISP_HAVE_OPENCV))
 
#if defined(ENABLE_VISP_NAMESPACE)
using namespace VISP_NAMESPACE_NAME;
#endif

void usage(const char *name, const char *badparam)
{
  fprintf(stdout, "\n\
Demonstration of the wireframe simulator with a simple visual servoing.\n\
          \n\
The visual servoing consists in bringing the camera at a desired position from the object.\n\
          \n\
The visual features used to compute the pose of the camera and thus the control law are special moments computed with the sphere's parameters.\n\
          \n\
SYNOPSIS\n\
  %s [-d]  [-p] [-h]\n",
          name);
 
  fprintf(stdout, "\n\
OPTIONS:                                               Default\n\
  -d \n\
     Turn off the display.\n\
            \n\
  -p \n\
     Turn off the plotter.\n\
                                    \n\
  -h\n\
     Print the help.\n");
 
  if (badparam)
    fprintf(stdout, "\nERROR: Bad parameter [%s]\n", badparam);
}

bool getOptions(int argc, const char **argv, bool &display, bool &plot)
{
  const char *optarg_;
  int c;
  while ((c = vpParseArgv::parse(argc, argv, GETOPTARGS, &optarg_)) > 1) {
 
    switch (c) {
    case 'd':
      display = false;
      break;
    case 'p':
      plot = false;
      break;
    case 'h':
      usage(argv[0], nullptr);
      return false;
 
    default:
      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;
}
 
/*
  Computes the virtual visual features corresponding to the sphere and stores
  it in the generic feature.
 
  The visual feature vector is computed thanks to the following formula : s =
  {sx, sy, sz} sx = gx*h2/(sqrt(h2+1) sx = gy*h2/(sqrt(h2+1) sz = sqrt(h2+1)
 
  with gx and gy the center of gravity of the ellipse,
  with h2 = (gx²+gy²)/(4*n20*gy²+4*n02*gx²-8n11gxgy)
  with n20,n02,n11 the second order centered moments of the sphere normalized by its area
  (i.e., such that \f$n_{ij} = \mu_{ij}/a\f$ where \f$\mu_{ij}\f$ are the centered moments and a the area)
*/
void computeVisualFeatures(const vpSphere &sphere, vpGenericFeature &s)
{
  double gx = sphere.get_x();
  double gy = sphere.get_y();
  double n02 = sphere.get_n02();
  double n20 = sphere.get_n20();
  double n11 = sphere.get_n11();
  double h2;
  // if (gx != 0 || gy != 0)
  if (std::fabs(gx) > std::numeric_limits<double>::epsilon() || std::fabs(gy) > std::numeric_limits<double>::epsilon())
    h2 = (vpMath::sqr(gx) + vpMath::sqr(gy)) /
    (4 * n20 * vpMath::sqr(gy) + 4 * n02 * vpMath::sqr(gx) - 8 * n11 * gx * gy);
  else
    h2 = 1 / (4 * n20);
 
  double sx = gx * h2 / (sqrt(h2 + 1));
  double sy = gy * h2 / (sqrt(h2 + 1));
  double sz = sqrt(h2 + 1); //(h2-(vpMath::sqr(sx)+vpMath::sqr(sy)-1))/(2*sqrt(h2));
 
  s.set_s(sx, sy, sz);
}
 
/*
  Computes the interaction matrix such as L = [-1/R*I3 [s]x]
 
  with R the radius of the sphere
  with I3 the 3x3 identity matrix
  with [s]x the skew matrix related to s
*/
void computeInteractionMatrix(const vpGenericFeature &s, const vpSphere &sphere, vpMatrix &L)
{
  L = 0;
  L[0][0] = -1 / sphere.getR();
  L[1][1] = -1 / sphere.getR();
  L[2][2] = -1 / sphere.getR();
 
  double s0, s1, s2;
  s.get_s(s0, s1, s2);
 
  vpTranslationVector c(s0, s1, s2);
  vpMatrix sk;
  sk = c.skew();
 
  for (unsigned int i = 0; i < 3; i++)
    for (unsigned int j = 0; j < 3; j++)
      L[i][j + 3] = sk[i][j];
}
 
int main(int argc, const char **argv)
{
  const unsigned int NB_DISPLAYS = 3;
#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
  std::shared_ptr<vpDisplay> display[NB_DISPLAYS];
  for (unsigned int i = 0; i < NB_DISPLAYS; ++i) {
    display[i] = vpDisplayFactory::createDisplay();
  }
#else
  vpDisplay *display[NB_DISPLAYS];
  for (unsigned int i = 0; i < NB_DISPLAYS; ++i) {
    display[i] = vpDisplayFactory::allocateDisplay();
  }
#endif
  unsigned int exit_status = EXIT_SUCCESS;
  try {
    bool opt_display = true;
    bool opt_plot = true;
 
    // Read the command line options
    if (getOptions(argc, argv, opt_display, opt_plot) == false) {
      return EXIT_FAILURE;
    }
 
    vpImage<vpRGBa> Iint(480, 640, vpRGBa(255));
    vpImage<vpRGBa> Iext1(480, 640, vpRGBa(255));
    vpImage<vpRGBa> Iext2(480, 640, vpRGBa(255));
 
    if (opt_display) {
      // Display size is automatically defined by the image (I) size
      display[0]->init(Iint, 100, 100, "The internal view");
      display[1]->init(Iext1, 100, 100, "The first external view");
      display[2]->init(Iext2, 100, 100, "The second external view");
      vpDisplay::setWindowPosition(Iint, 0, 0);
      vpDisplay::setWindowPosition(Iext1, 750, 0);
      vpDisplay::setWindowPosition(Iext2, 0, 550);
      vpDisplay::display(Iint);
      vpDisplay::flush(Iint);
      vpDisplay::display(Iext1);
      vpDisplay::flush(Iext1);
      vpDisplay::display(Iext2);
      vpDisplay::flush(Iext2);
    }
 
    vpPlot *plotter = nullptr;
 
    vpServo task;
    vpSimulatorCamera robot;
    float sampling_time = 0.020f; // Sampling period in second
    robot.setSamplingTime(sampling_time);
 
    // Since the task gain lambda is very high, we need to increase default
    // max velocities
    robot.setMaxTranslationVelocity(10);
    robot.setMaxRotationVelocity(vpMath::rad(180));
 
    // Set initial position of the object in the camera frame
    vpHomogeneousMatrix cMo(0, 0.1, 2.0, vpMath::rad(35), vpMath::rad(25), 0);
    // Set desired position of the object in the camera frame
    vpHomogeneousMatrix cdMo(0.0, 0.0, 0.8, vpMath::rad(0), vpMath::rad(0), vpMath::rad(0));
    // Set initial position of the object in the world frame
    vpHomogeneousMatrix wMo(0.0, 0.0, 0, 0, 0, 0);
    // Position of the camera in the world frame
    vpHomogeneousMatrix wMc;
    wMc = wMo * cMo.inverse();
 
    robot.setPosition(wMc);
 
    // The sphere
    vpSphere sphere(0, 0, 0, 0.15);
 
    // Projection of the sphere
    sphere.track(cMo);
 
    // Set the current visual feature
    vpGenericFeature s(3);
    computeVisualFeatures(sphere, s);
 
    // Projection of the points
    sphere.track(cdMo);
 
    vpGenericFeature sd(3);
    computeVisualFeatures(sphere, sd);
 
    vpMatrix L(3, 6);
    computeInteractionMatrix(sd, sphere, L);
    sd.setInteractionMatrix(L);
 
    task.setServo(vpServo::EYEINHAND_L_cVe_eJe);
    task.setInteractionMatrixType(vpServo::DESIRED);
 
    vpHomogeneousMatrix cMe;
    vpVelocityTwistMatrix cVe(cMe);
    task.set_cVe(cVe);
 
    vpMatrix eJe;
    robot.get_eJe(eJe);
    task.set_eJe(eJe);
 
    task.addFeature(s, sd);
 
    task.setLambda(7);
 
    if (opt_plot) {
      plotter = new vpPlot(2, 480, 640, 750, 550, "Real time curves plotter");
      plotter->setTitle(0, "Visual features error");
      plotter->setTitle(1, "Camera velocities");
      plotter->initGraph(0, task.getDimension());
      plotter->initGraph(1, 6);
      plotter->setLegend(0, 0, "error_feat_sx");
      plotter->setLegend(0, 1, "error_feat_sy");
      plotter->setLegend(0, 2, "error_feat_sz");
      plotter->setLegend(1, 0, "vc_x");
      plotter->setLegend(1, 1, "vc_y");
      plotter->setLegend(1, 2, "vc_z");
      plotter->setLegend(1, 3, "wc_x");
      plotter->setLegend(1, 4, "wc_y");
      plotter->setLegend(1, 5, "wc_z");
    }
 
    vpWireFrameSimulator sim;
 
    // Set the scene
    sim.initScene(vpWireFrameSimulator::SPHERE, vpWireFrameSimulator::D_STANDARD);
 
    // Initialize simulator frames
    sim.set_fMo(wMo);                   // Position of the object in the world reference frame
    sim.setCameraPositionRelObj(cMo);   // Initial position of the object in the camera frame
    sim.setDesiredCameraPosition(cdMo); // Desired position of the object in the camera frame
 
    // Set the External camera position
    vpHomogeneousMatrix camMf(0.0, 0, 3.5, vpMath::rad(0), vpMath::rad(30), 0);
    sim.setExternalCameraPosition(camMf);
 
    // Computes the position of a camera which is fixed in the object frame
    vpHomogeneousMatrix camoMf(0, 0.0, 2.5, 0, vpMath::rad(140), 0);
    camoMf = camoMf * (sim.get_fMo().inverse());
 
    // Set the parameters of the cameras (internal and external)
    vpCameraParameters camera(1000, 1000, 320, 240);
    sim.setInternalCameraParameters(camera);
    sim.setExternalCameraParameters(camera);
 
    int max_iter = 10;
 
    if (opt_display) {
      max_iter = 1000;
      // Get the internal and external views
      sim.getInternalImage(Iint);
      sim.getExternalImage(Iext1);
      sim.getExternalImage(Iext2, camoMf);
 
      // Display the object frame (current and desired position)
      vpDisplay::displayFrame(Iint, cMo, camera, 0.2, vpColor::none);
      vpDisplay::displayFrame(Iint, cdMo, camera, 0.2, vpColor::none);
 
      // Display the object frame the world reference frame and the camera
      // frame
      vpDisplay::displayFrame(Iext1, camMf * sim.get_fMo() * cMo.inverse(), camera, 0.2, vpColor::none);
      vpDisplay::displayFrame(Iext1, camMf * sim.get_fMo(), camera, 0.2, vpColor::none);
      vpDisplay::displayFrame(Iext1, camMf, camera, 0.2, vpColor::none);
 
      // Display the world reference frame and the object frame
      vpDisplay::displayFrame(Iext2, camoMf, camera, 0.2, vpColor::none);
      vpDisplay::displayFrame(Iext2, camoMf * sim.get_fMo(), camera, 0.05, vpColor::none);
 
      vpDisplay::displayText(Iint, 20, 20, "Click to start visual servo", vpColor::red);
 
      vpDisplay::flush(Iint);
      vpDisplay::flush(Iext1);
      vpDisplay::flush(Iext2);
 
      std::cout << "Click on a display" << std::endl;
      while (!vpDisplay::getClick(Iint, false) && !vpDisplay::getClick(Iext1, false) &&
             !vpDisplay::getClick(Iext2, false)) {
      }
    }
 
    // Print the task
    task.print();
 
    int iter = 0;
    bool stop = false;
    vpColVector v;
 
    double t_prev, t = vpTime::measureTimeMs();
 
    while (iter++ < max_iter && !stop) {
      t_prev = t;
      t = vpTime::measureTimeMs();
 
      if (opt_display) {
        vpDisplay::display(Iint);
        vpDisplay::display(Iext1);
        vpDisplay::display(Iext2);
      }
 
      robot.get_eJe(eJe);
      task.set_eJe(eJe);
 
      wMc = robot.getPosition();
      cMo = wMc.inverse() * wMo;
 
      sphere.track(cMo);
 
      // Set the current visual feature
      computeVisualFeatures(sphere, s);
 
      v = task.computeControlLaw();
      robot.setVelocity(vpRobot::CAMERA_FRAME, v);
      sim.setCameraPositionRelObj(cMo);
 
      // Compute the position of the external view which is fixed in the object frame
      camoMf.buildFrom(0, 0.0, 2.5, 0, vpMath::rad(150), 0);
      camoMf = camoMf * (sim.get_fMo().inverse());
 
      if (opt_plot) {
        plotter->plot(0, iter, task.getError());
        plotter->plot(1, iter, v);
      }
 
      if (opt_display) {
        // Get the internal and external views
        sim.getInternalImage(Iint);
        sim.getExternalImage(Iext1);
        sim.getExternalImage(Iext2, camoMf);
 
        // Display the object frame (current and desired position)
        vpDisplay::displayFrame(Iint, cMo, camera, 0.2, vpColor::none);
        vpDisplay::displayFrame(Iint, cdMo, camera, 0.2, vpColor::none);
 
        // Display the camera frame, the object frame the world reference
        // frame
        vpDisplay::displayFrame(Iext1, sim.getExternalCameraPosition() * sim.get_fMo() * cMo.inverse(), camera, 0.2,
                                vpColor::none);
        vpDisplay::displayFrame(Iext1, sim.getExternalCameraPosition() * sim.get_fMo(), camera, 0.2, vpColor::none);
        vpDisplay::displayFrame(Iext1, sim.getExternalCameraPosition(), camera, 0.2, vpColor::none);
 
        // Display the world reference frame and the object frame
        vpDisplay::displayFrame(Iext2, camoMf, camera, 0.2, vpColor::none);
        vpDisplay::displayFrame(Iext2, camoMf * sim.get_fMo(), camera, 0.05, vpColor::none);
 
        vpDisplay::displayText(Iint, 20, 20, "Click to stop visual servo", vpColor::red);
 
        std::stringstream ss;
        ss << "Loop time: " << t - t_prev << " ms";
        vpDisplay::displayText(Iint, 40, 20, ss.str(), vpColor::red);
 
        if (vpDisplay::getClick(Iint, false)) {
          stop = true;
        }
 
        vpDisplay::flush(Iint);
        vpDisplay::flush(Iext1);
        vpDisplay::flush(Iext2);
 
        vpTime::wait(t, sampling_time * 1000); // Wait ms
      }
 
      std::cout << "|| s - s* || = " << (task.getError()).sumSquare() << std::endl;
    }
 
    if (opt_plot && plotter != nullptr) {
      vpDisplay::display(Iint);
      sim.getInternalImage(Iint);
      vpDisplay::displayFrame(Iint, cMo, camera, 0.2, vpColor::none);
      vpDisplay::displayFrame(Iint, cdMo, camera, 0.2, vpColor::none);
      vpDisplay::displayText(Iint, 20, 20, "Click to quit", vpColor::red);
      if (vpDisplay::getClick(Iint)) {
        stop = true;
      }
      vpDisplay::flush(Iint);
 
      delete plotter;
    }
 
    task.print();
    exit_status = EXIT_SUCCESS;
  }
  catch (const vpException &e) {
    std::cout << "Catch an exception: " << e << std::endl;
    exit_status = EXIT_FAILURE;
  }
 
#if (VISP_CXX_STANDARD < VISP_CXX_STANDARD_11)
  for (unsigned int i = 0; i < NB_DISPLAYS; ++i) {
    delete display[i];
  }
#endif
 
  return exit_status;
}
#elif !(defined(VISP_HAVE_LAPACK) || defined(VISP_HAVE_EIGEN3) || defined(VISP_HAVE_OPENCV))
int main()
{
  std::cout << "Cannot run this example: install Lapack, Eigen3 or OpenCV" << std::endl;
  return EXIT_SUCCESS;
}
#else
int main()
{
  std::cout << "You do not have X11, or GDI (Graphical Device Interface), or GTK functionalities to display images..."
    << std::endl;
  std::cout << "Tip if you are on a unix-like system:" << std::endl;
  std::cout << "- Install X11, configure again ViSP using cmake and build again this example" << std::endl;
  std::cout << "Tip if you are on a windows-like system:" << std::endl;
  std::cout << "- Install GDI, configure again ViSP using cmake and build again this example" << std::endl;
  return EXIT_SUCCESS;
}
#endif