vpMbKltTracker.cpp

/****************************************************************************
 *
 * 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 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:
 * Model based tracker using only KLT
 *
*****************************************************************************/
 
#include <visp3/core/vpImageConvert.h>
#include <visp3/core/vpTrackingException.h>
#include <visp3/core/vpVelocityTwistMatrix.h>
#include <visp3/mbt/vpMbKltTracker.h>
#include <visp3/mbt/vpMbtXmlGenericParser.h>
 
#if defined(VISP_HAVE_MODULE_KLT) && defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_VIDEO)
 
#if defined(__APPLE__) && defined(__MACH__) // Apple OSX and iOS (Darwin)
#include <TargetConditionals.h>             // To detect OSX or IOS using TARGET_OS_IPHONE or TARGET_OS_IOS macro
#endif
 
namespace
{
vpMatrix homography2collineation(const vpMatrix &H, const vpCameraParameters &cam)
{
  vpMatrix G(3, 3);
  double px = cam.get_px();
  double py = cam.get_py();
  double u0 = cam.get_u0();
  double v0 = cam.get_v0();
  double one_over_px = cam.get_px_inverse();
  double one_over_py = cam.get_py_inverse();
  double h00 = H[0][0], h01 = H[0][1], h02 = H[0][2];
  double h10 = H[1][0], h11 = H[1][1], h12 = H[1][2];
  double h20 = H[2][0], h21 = H[2][1], h22 = H[2][2];
 
  double A = h00 * px + u0 * h20;
  double B = h01 * px + u0 * h21;
  double C = h02 * px + u0 * h22;
  double D = h10 * py + v0 * h20;
  double E = h11 * py + v0 * h21;
  double F = h12 * py + v0 * h22;
 
  G[0][0] = A * one_over_px;
  G[1][0] = D * one_over_px;
  G[2][0] = h20 * one_over_px;
 
  G[0][1] = B * one_over_py;
  G[1][1] = E * one_over_py;
  G[2][1] = h21 * one_over_py;
 
  double u0_one_over_px = u0 * one_over_px;
  double v0_one_over_py = v0 * one_over_py;
 
  G[0][2] = -A * u0_one_over_px - B * v0_one_over_py + C;
  G[1][2] = -D * u0_one_over_px - E * v0_one_over_py + F;
  G[2][2] = -h20 * u0_one_over_px - h21 * v0_one_over_py + h22;
 
  return G;
}
} // namespace
 
vpMbKltTracker::vpMbKltTracker()
  :
  cur(), c0Mo(), firstInitialisation(true), maskBorder(5), threshold_outlier(0.5), percentGood(0.6), ctTc0(), tracker(),
  kltPolygons(), kltCylinders(), circles_disp(), m_nbInfos(0), m_nbFaceUsed(0), m_L_klt(), m_error_klt(), m_w_klt(),
  m_weightedError_klt(), m_robust_klt(), m_featuresToBeDisplayedKlt()
{
  tracker.setTrackerId(1);
  tracker.setUseHarris(1);
  tracker.setMaxFeatures(10000);
  tracker.setWindowSize(5);
  tracker.setQuality(0.01);
  tracker.setMinDistance(5);
  tracker.setHarrisFreeParameter(0.01);
  tracker.setBlockSize(3);
  tracker.setPyramidLevels(3);
 
#ifdef VISP_HAVE_OGRE
  faces.getOgreContext()->setWindowName("MBT Klt");
#endif
 
  m_lambda = 0.8;
  m_maxIter = 200;
}
 
vpMbKltTracker::~vpMbKltTracker()
{
  // delete the Klt Polygon features
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    if (kltpoly != nullptr) {
      delete kltpoly;
    }
    kltpoly = nullptr;
  }
  kltPolygons.clear();
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
    if (kltPolyCylinder != nullptr) {
      delete kltPolyCylinder;
    }
    kltPolyCylinder = nullptr;
  }
  kltCylinders.clear();
 
  // delete the structures used to display circles
  for (std::list<vpMbtDistanceCircle *>::const_iterator it = circles_disp.begin(); it != circles_disp.end(); ++it) {
    vpMbtDistanceCircle *ci = *it;
    if (ci != nullptr) {
      delete ci;
    }
    ci = nullptr;
  }
 
  circles_disp.clear();
}
 
void vpMbKltTracker::init(const vpImage<unsigned char> &I)
{
  if (!modelInitialised) {
    throw vpException(vpException::fatalError, "model not initialized");
  }
 
  bool reInitialisation = false;
  if (!useOgre)
    faces.setVisible(I.getWidth(), I.getHeight(), m_cam, m_cMo, angleAppears, angleDisappears, reInitialisation);
  else {
#ifdef VISP_HAVE_OGRE
    if (!faces.isOgreInitialised()) {
      faces.setBackgroundSizeOgre(I.getHeight(), I.getWidth());
      faces.setOgreShowConfigDialog(ogreShowConfigDialog);
      faces.initOgre(m_cam);
      // Turn off Ogre config dialog display for the next call to this
      // function since settings are saved in the ogre.cfg file and used
      // during the next call
      ogreShowConfigDialog = false;
    }
 
    faces.setVisibleOgre(I.getWidth(), I.getHeight(), m_cam, m_cMo, angleAppears, angleDisappears, reInitialisation);
 
#else
    faces.setVisible(I.getWidth(), I.getHeight(), m_cam, m_cMo, angleAppears, angleDisappears, reInitialisation);
#endif
  }
  reinit(I);
}
 
void vpMbKltTracker::reinit(const vpImage<unsigned char> &I)
{
  c0Mo = m_cMo;
  ctTc0.eye();
 
  vpImageConvert::convert(I, cur);
 
  m_cam.computeFov(I.getWidth(), I.getHeight());
 
  if (useScanLine) {
    faces.computeClippedPolygons(m_cMo, m_cam);
    faces.computeScanLineRender(m_cam, I.getWidth(), I.getHeight());
  }
 
  // mask
  cv::Mat mask((int)I.getRows(), (int)I.getCols(), CV_8UC1, cv::Scalar(0));
 
  vpMbtDistanceKltPoints *kltpoly;
  vpMbtDistanceKltCylinder *kltPolyCylinder;
  if (useScanLine) {
    vpImageConvert::convert(faces.getMbScanLineRenderer().getMask(), mask);
  }
  else {
    unsigned char val = 255 /* - i*15*/;
    for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
      kltpoly = *it;
      if (kltpoly->polygon->isVisible() && kltpoly->isTracked() && kltpoly->polygon->getNbPoint() > 2) {
        // need to changeFrame when reinit() is called by postTracking
        // other solution is
        kltpoly->polygon->changeFrame(m_cMo);
        kltpoly->polygon->computePolygonClipped(m_cam); // Might not be necessary when scanline is activated
        kltpoly->updateMask(mask, val, maskBorder);
      }
    }
 
    for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
         ++it) {
      kltPolyCylinder = *it;
 
      if (kltPolyCylinder->isTracked()) {
        for (unsigned int k = 0; k < kltPolyCylinder->listIndicesCylinderBBox.size(); k++) {
          unsigned int indCylBBox = (unsigned int)kltPolyCylinder->listIndicesCylinderBBox[k];
          if (faces[indCylBBox]->isVisible() && faces[indCylBBox]->getNbPoint() > 2u) {
            faces[indCylBBox]->computePolygonClipped(m_cam); // Might not be necessary when scanline is activated
          }
        }
 
        kltPolyCylinder->updateMask(mask, val, maskBorder);
      }
    }
  }
 
  tracker.initTracking(cur, mask);
  //  tracker.track(cur); // AY: Not sure to be usefull but makes sure that
  //  the points are valid for tracking and avoid too fast reinitialisations.
  //  vpCTRACE << "init klt. detected " << tracker.getNbFeatures() << "
  //  points" << std::endl;
 
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    kltpoly = *it;
    if (kltpoly->polygon->isVisible() && kltpoly->isTracked() && kltpoly->polygon->getNbPoint() > 2) {
      kltpoly->init(tracker, m_mask);
    }
  }
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    kltPolyCylinder = *it;
 
    if (kltPolyCylinder->isTracked())
      kltPolyCylinder->init(tracker, m_cMo);
  }
}
 
void vpMbKltTracker::resetTracker()
{
  m_cMo.eye();
 
  // delete the Klt Polygon features
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    if (kltpoly != nullptr) {
      delete kltpoly;
    }
    kltpoly = nullptr;
  }
  kltPolygons.clear();
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
    if (kltPolyCylinder != nullptr) {
      delete kltPolyCylinder;
    }
    kltPolyCylinder = nullptr;
  }
  kltCylinders.clear();
 
  // delete the structures used to display circles
  for (std::list<vpMbtDistanceCircle *>::const_iterator it = circles_disp.begin(); it != circles_disp.end(); ++it) {
    vpMbtDistanceCircle *ci = *it;
    if (ci != nullptr) {
      delete ci;
    }
    ci = nullptr;
  }
 
  circles_disp.clear();
 
  m_computeInteraction = true;
  firstInitialisation = true;
  computeCovariance = false;
 
  tracker.setTrackerId(1);
  tracker.setUseHarris(1);
 
  tracker.setMaxFeatures(10000);
  tracker.setWindowSize(5);
  tracker.setQuality(0.01);
  tracker.setMinDistance(5);
  tracker.setHarrisFreeParameter(0.01);
  tracker.setBlockSize(3);
  tracker.setPyramidLevels(3);
 
  angleAppears = vpMath::rad(89);
  angleDisappears = vpMath::rad(89);
 
  clippingFlag = vpPolygon3D::NO_CLIPPING;
 
  maskBorder = 5;
  threshold_outlier = 0.5;
  percentGood = 0.6;
 
  m_lambda = 0.8;
  m_maxIter = 200;
 
  faces.reset();
 
  m_optimizationMethod = vpMbTracker::GAUSS_NEWTON_OPT;
 
  useScanLine = false;
 
#ifdef VISP_HAVE_OGRE
  useOgre = false;
#endif
}
 
std::vector<vpImagePoint> vpMbKltTracker::getKltImagePoints() const
{
  std::vector<vpImagePoint> kltPoints;
  for (unsigned int i = 0; i < static_cast<unsigned int>(tracker.getNbFeatures()); i++) {
    long id;
    float x_tmp, y_tmp;
    tracker.getFeature((int)i, id, x_tmp, y_tmp);
    kltPoints.push_back(vpImagePoint(y_tmp, x_tmp));
  }
 
  return kltPoints;
}
 
std::map<int, vpImagePoint> vpMbKltTracker::getKltImagePointsWithId() const
{
  std::map<int, vpImagePoint> kltPoints;
  for (unsigned int i = 0; i < static_cast<unsigned int>(tracker.getNbFeatures()); i++) {
    long id;
    float x_tmp, y_tmp;
    tracker.getFeature((int)i, id, x_tmp, y_tmp);
#ifdef TARGET_OS_IPHONE
    kltPoints[(int)id] = vpImagePoint(y_tmp, x_tmp);
#else
    kltPoints[id] = vpImagePoint(y_tmp, x_tmp);
#endif
  }
 
  return kltPoints;
}
 
void vpMbKltTracker::setKltOpencv(const vpKltOpencv &t)
{
  tracker.setMaxFeatures(t.getMaxFeatures());
  tracker.setWindowSize(t.getWindowSize());
  tracker.setQuality(t.getQuality());
  tracker.setMinDistance(t.getMinDistance());
  tracker.setHarrisFreeParameter(t.getHarrisFreeParameter());
  tracker.setBlockSize(t.getBlockSize());
  tracker.setPyramidLevels(t.getPyramidLevels());
}
 
void vpMbKltTracker::setCameraParameters(const vpCameraParameters &cam)
{
  //  for (unsigned int i = 0; i < faces.size(); i += 1){
  //    faces[i]->setCameraParameters(camera);
  //  }
 
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    kltpoly->setCameraParameters(cam);
  }
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
    kltPolyCylinder->setCameraParameters(cam);
  }
 
  m_cam = cam;
}
 
void vpMbKltTracker::setPose(const vpImage<unsigned char> *const I, const vpImage<vpRGBa> *const I_color,
                             const vpHomogeneousMatrix &cdMo)
{
  if (I_color) {
    vpImageConvert::convert(*I_color, m_I);
  }
 
  if (!kltCylinders.empty()) {
    std::cout << "WARNING: Cannot set pose when model contains cylinder(s). "
      "This feature is not implemented yet."
      << std::endl;
    std::cout << "Tracker will be reinitialized with the given pose." << std::endl;
    m_cMo = cdMo;
    if (I) {
      init(*I);
    }
    else {
      init(m_I);
    }
  }
  else {
    vpMbtDistanceKltPoints *kltpoly;
 
    std::vector<cv::Point2f> init_pts;
    std::vector<long> init_ids;
    std::vector<cv::Point2f> guess_pts;
 
    vpHomogeneousMatrix cdMc = cdMo * m_cMo.inverse();
    vpHomogeneousMatrix cMcd = cdMc.inverse();
 
    vpRotationMatrix cdRc;
    vpTranslationVector cdtc;
 
    cdMc.extract(cdRc);
    cdMc.extract(cdtc);
 
    // unsigned int nbCur = 0;
 
    for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
      kltpoly = *it;
 
      if (kltpoly->polygon->isVisible() && kltpoly->polygon->getNbPoint() > 2) {
        kltpoly->polygon->changeFrame(cdMo);
 
        // Get the normal to the face at the current state cMo
        vpPlane plan(kltpoly->polygon->p[0], kltpoly->polygon->p[1], kltpoly->polygon->p[2]);
        plan.changeFrame(cMcd);
 
        vpColVector Nc = plan.getNormal();
        Nc.normalize();
 
        double invDc = 1.0 / plan.getD();
 
        // Create the homography
        vpMatrix cdHc;
        vpGEMM(cdtc, Nc, -invDc, cdRc, 1.0, cdHc, VP_GEMM_B_T);
        cdHc /= cdHc[2][2];
 
        // Compute homography in the pixel space cdGc = K * cdHc * K^{-1}
        vpMatrix cdGc = homography2collineation(cdHc, m_cam);
 
        // Points displacement
        std::map<int, vpImagePoint>::const_iterator iter = kltpoly->getCurrentPoints().begin();
        // nbCur+= (unsigned int)kltpoly->getCurrentPoints().size();
        for (; iter != kltpoly->getCurrentPoints().end(); ++iter) {
#ifdef TARGET_OS_IPHONE
          if (std::find(init_ids.begin(), init_ids.end(), (long)(kltpoly->getCurrentPointsInd())[(int)iter->first]) !=
              init_ids.end())
#else
          if (std::find(init_ids.begin(), init_ids.end(),
                        (long)(kltpoly->getCurrentPointsInd())[(size_t)iter->first]) != init_ids.end())
#endif
          {
            // KLT point already processed (a KLT point can exist in another
            // vpMbtDistanceKltPoints due to possible overlapping faces)
            continue;
          }
 
          vpColVector cdp(3);
          cdp[0] = iter->second.get_j();
          cdp[1] = iter->second.get_i();
          cdp[2] = 1.0;
 
          cv::Point2f p((float)cdp[0], (float)cdp[1]);
          init_pts.push_back(p);
#ifdef TARGET_OS_IPHONE
          init_ids.push_back((size_t)(kltpoly->getCurrentPointsInd())[(int)iter->first]);
#else
          init_ids.push_back((size_t)(kltpoly->getCurrentPointsInd())[(size_t)iter->first]);
#endif
 
          double p_mu_t_2 = cdp[0] * cdGc[2][0] + cdp[1] * cdGc[2][1] + cdGc[2][2];
 
          if (fabs(p_mu_t_2) < std::numeric_limits<double>::epsilon()) {
            cdp[0] = 0.0;
            cdp[1] = 0.0;
            throw vpException(vpException::divideByZeroError, "the depth of the point is calculated to zero");
          }
 
          cdp[0] = (cdp[0] * cdGc[0][0] + cdp[1] * cdGc[0][1] + cdGc[0][2]) / p_mu_t_2;
          cdp[1] = (cdp[0] * cdGc[1][0] + cdp[1] * cdGc[1][1] + cdGc[1][2]) / p_mu_t_2;
 
          // Set value to the KLT tracker
          cv::Point2f p_guess((float)cdp[0], (float)cdp[1]);
          guess_pts.push_back(p_guess);
        }
      }
    }
 
    if (I) {
      vpImageConvert::convert(*I, cur);
    }
    else {
      vpImageConvert::convert(m_I, cur);
    }
 
    tracker.setInitialGuess(init_pts, guess_pts, init_ids);
 
    bool reInitialisation = false;
    if (!useOgre) {
      if (I) {
        faces.setVisible(I->getWidth(), I->getHeight(), m_cam, cdMo, angleAppears, angleDisappears, reInitialisation);
      }
      else {
        faces.setVisible(m_I.getWidth(), m_I.getHeight(), m_cam, cdMo, angleAppears, angleDisappears, reInitialisation);
      }
    }
    else {
#ifdef VISP_HAVE_OGRE
      if (I) {
        faces.setVisibleOgre(I->getWidth(), I->getHeight(), m_cam, cdMo, angleAppears, angleDisappears,
                             reInitialisation);
      }
      else {
        faces.setVisibleOgre(m_I.getWidth(), m_I.getHeight(), m_cam, cdMo, angleAppears, angleDisappears,
                             reInitialisation);
      }
#else
      if (I) {
        faces.setVisible(I->getWidth(), I->getHeight(), m_cam, cdMo, angleAppears, angleDisappears, reInitialisation);
      }
      else {
        faces.setVisible(m_I.getWidth(), m_I.getHeight(), m_cam, cdMo, angleAppears, angleDisappears, reInitialisation);
      }
#endif
    }
 
    m_cam.computeFov(I ? I->getWidth() : m_I.getWidth(), I ? I->getHeight() : m_I.getHeight());
 
    if (useScanLine) {
      faces.computeClippedPolygons(cdMo, m_cam);
      faces.computeScanLineRender(m_cam, I ? I->getWidth() : m_I.getWidth(), I ? I->getHeight() : m_I.getHeight());
    }
 
    for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
      kltpoly = *it;
      if (kltpoly->polygon->isVisible() && kltpoly->polygon->getNbPoint() > 2) {
        kltpoly->polygon->computePolygonClipped(m_cam);
        kltpoly->init(tracker, m_mask);
      }
    }
 
    m_cMo = cdMo;
    c0Mo = m_cMo;
    ctTc0.eye();
  }
}
 
void vpMbKltTracker::setPose(const vpImage<unsigned char> &I, const vpHomogeneousMatrix &cdMo)
{
  vpMbKltTracker::setPose(&I, nullptr, cdMo);
}
 
void vpMbKltTracker::setPose(const vpImage<vpRGBa> &I_color, const vpHomogeneousMatrix &cdMo)
{
  vpMbKltTracker::setPose(nullptr, &I_color, cdMo);
}
 
void vpMbKltTracker::initFaceFromCorners(vpMbtPolygon &polygon)
{
  vpMbtDistanceKltPoints *kltPoly = new vpMbtDistanceKltPoints();
  kltPoly->setCameraParameters(m_cam);
  kltPoly->polygon = &polygon;
  kltPoly->hiddenface = &faces;
  kltPoly->useScanLine = useScanLine;
  kltPolygons.push_back(kltPoly);
}
void vpMbKltTracker::initFaceFromLines(vpMbtPolygon &polygon)
{
  vpMbtDistanceKltPoints *kltPoly = new vpMbtDistanceKltPoints();
  kltPoly->setCameraParameters(m_cam);
  kltPoly->polygon = &polygon;
  kltPoly->hiddenface = &faces;
  kltPoly->useScanLine = useScanLine;
  kltPolygons.push_back(kltPoly);
}
 
void vpMbKltTracker::preTracking(const vpImage<unsigned char> &I)
{
  vpImageConvert::convert(I, cur);
  tracker.track(cur);
 
  m_nbInfos = 0;
  m_nbFaceUsed = 0;
  //  for (unsigned int i = 0; i < faces.size(); i += 1){
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    if (kltpoly->polygon->isVisible() && kltpoly->isTracked() && kltpoly->polygon->getNbPoint() > 2) {
      kltpoly->computeNbDetectedCurrent(tracker, m_mask);
      //       faces[i]->ransac();
      if (kltpoly->hasEnoughPoints()) {
        m_nbInfos += kltpoly->getCurrentNumberPoints();
        m_nbFaceUsed++;
      }
    }
  }
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
 
    if (kltPolyCylinder->isTracked()) {
      kltPolyCylinder->computeNbDetectedCurrent(tracker);
      if (kltPolyCylinder->hasEnoughPoints()) {
        m_nbInfos += kltPolyCylinder->getCurrentNumberPoints();
        m_nbFaceUsed++;
      }
    }
  }
}
 
bool vpMbKltTracker::postTracking(const vpImage<unsigned char> &I, vpColVector &w)
{
  // # For a better Post Tracking, tracker should reinitialize if so faces
  // don't have enough points but are visible. # Here we are not doing it for
  // more speed performance.
  bool reInitialisation = false;
 
  unsigned int initialNumber = 0;
  unsigned int currentNumber = 0;
  unsigned int shift = 0;
  //  for (unsigned int i = 0; i < faces.size(); i += 1){
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    if (kltpoly->polygon->isVisible() && kltpoly->isTracked() && kltpoly->polygon->getNbPoint() > 2) {
      initialNumber += kltpoly->getInitialNumberPoint();
      if (kltpoly->hasEnoughPoints()) {
        vpSubColVector sub_w(w, shift, 2 * kltpoly->getCurrentNumberPoints());
        shift += 2 * kltpoly->getCurrentNumberPoints();
        kltpoly->removeOutliers(sub_w, threshold_outlier);
 
        currentNumber += kltpoly->getCurrentNumberPoints();
      }
      //       else{
      //         reInitialisation = true;
      //         break;
      //       }
    }
  }
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
 
    if (kltPolyCylinder->isTracked()) {
      initialNumber += kltPolyCylinder->getInitialNumberPoint();
      if (kltPolyCylinder->hasEnoughPoints()) {
        vpSubColVector sub_w(w, shift, 2 * kltPolyCylinder->getCurrentNumberPoints());
        shift += 2 * kltPolyCylinder->getCurrentNumberPoints();
        kltPolyCylinder->removeOutliers(sub_w, threshold_outlier);
 
        currentNumber += kltPolyCylinder->getCurrentNumberPoints();
      }
    }
  }
 
  //   if(!reInitialisation){
  double value = percentGood * (double)initialNumber;
  if ((double)currentNumber < value) {
    //     std::cout << "Too many point disappear : " << initialNumber << "/"
    //     << currentNumber << std::endl;
    reInitialisation = true;
  }
  else {
    if (!useOgre)
      faces.setVisible(I.getWidth(), I.getHeight(), m_cam, m_cMo, angleAppears, angleDisappears, reInitialisation);
    else {
#ifdef VISP_HAVE_OGRE
      faces.setVisibleOgre(I.getWidth(), I.getHeight(), m_cam, m_cMo, angleAppears, angleDisappears, reInitialisation);
#else
      faces.setVisible(I.getWidth(), I.getHeight(), m_cam, m_cMo, angleAppears, angleDisappears, reInitialisation);
#endif
    }
  }
  //   }
 
  if (reInitialisation)
    return true;
 
  return false;
}
 
void vpMbKltTracker::computeVVS()
{
  vpMatrix L_true; // interaction matrix without weighting
  vpMatrix LVJ_true;
  vpColVector v; // "speed" for VVS
 
  vpMatrix LTL;
  vpColVector LTR;
  vpHomogeneousMatrix cMoPrev;
  vpHomogeneousMatrix ctTc0_Prev;
  vpColVector error_prev;
  double mu = m_initialMu;
 
  double normRes = 0;
  double normRes_1 = -1;
  unsigned int iter = 0;
 
  bool isoJoIdentity = m_isoJoIdentity; // Backup since it can be modified if L is not full rank
  if (isoJoIdentity)
    oJo.eye();
 
  vpMbKltTracker::computeVVSInit();
 
  while (((int)((normRes - normRes_1) * 1e8) != 0) && (iter < m_maxIter)) {
    vpMbKltTracker::computeVVSInteractionMatrixAndResidu();
 
    bool reStartFromLastIncrement = false;
    computeVVSCheckLevenbergMarquardt(iter, m_error_klt, error_prev, cMoPrev, mu, reStartFromLastIncrement);
    if (reStartFromLastIncrement) {
      ctTc0 = ctTc0_Prev;
    }
 
    if (!reStartFromLastIncrement) {
      vpMbTracker::computeVVSWeights(m_robust_klt, m_error_klt, m_w_klt);
 
      if (computeCovariance) {
        L_true = m_L_klt;
        if (!isoJoIdentity) {
          vpVelocityTwistMatrix cVo;
          cVo.buildFrom(m_cMo);
          LVJ_true = (m_L_klt * cVo * oJo);
        }
      }
 
      normRes_1 = normRes;
      normRes = 0.0;
 
      for (unsigned int i = 0; i < m_error_klt.getRows(); i++) {
        m_weightedError_klt[i] = m_error_klt[i] * m_w_klt[i];
        normRes += m_weightedError_klt[i];
      }
 
      if ((iter == 0) || m_computeInteraction) {
        for (unsigned int i = 0; i < m_error_klt.getRows(); i++) {
          for (unsigned int j = 0; j < 6; j++) {
            m_L_klt[i][j] *= m_w_klt[i];
          }
        }
      }
 
      computeVVSPoseEstimation(m_isoJoIdentity, iter, m_L_klt, LTL, m_weightedError_klt, m_error_klt, error_prev, LTR, mu, v);
 
      cMoPrev = m_cMo;
      ctTc0_Prev = ctTc0;
      ctTc0 = vpExponentialMap::direct(v).inverse() * ctTc0;
      m_cMo = ctTc0 * c0Mo;
    } // endif(!reStartFromLastIncrement)
 
    iter++;
  }
 
  computeCovarianceMatrixVVS(m_isoJoIdentity, m_w_klt, cMoPrev, L_true, LVJ_true, m_error_klt);
}
 
void vpMbKltTracker::computeVVSInit()
{
  unsigned int nbFeatures = 2 * m_nbInfos;
 
  m_L_klt.resize(nbFeatures, 6, false, false);
  m_error_klt.resize(nbFeatures, false);
 
  m_weightedError_klt.resize(nbFeatures, false);
  m_w_klt.resize(nbFeatures, false);
  m_w_klt = 1;
 
  m_robust_klt.setMinMedianAbsoluteDeviation(2 / m_cam.get_px());
}
 
void vpMbKltTracker::computeVVSInteractionMatrixAndResidu()
{
  unsigned int shift = 0;
  vpHomography H;
 
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    if (kltpoly->polygon->isVisible() && kltpoly->isTracked() && kltpoly->polygon->getNbPoint() > 2 &&
        kltpoly->hasEnoughPoints()) {
      vpSubColVector subR(m_error_klt, shift, 2 * kltpoly->getCurrentNumberPoints());
      vpSubMatrix subL(m_L_klt, shift, 0, 2 * kltpoly->getCurrentNumberPoints(), 6);
 
      try {
        kltpoly->computeHomography(ctTc0, H);
        kltpoly->computeInteractionMatrixAndResidu(subR, subL);
      }
      catch (...) {
        throw vpTrackingException(vpTrackingException::fatalError, "Cannot compute interaction matrix");
      }
 
      shift += 2 * kltpoly->getCurrentNumberPoints();
    }
  }
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
 
    if (kltPolyCylinder->isTracked() && kltPolyCylinder->hasEnoughPoints()) {
      vpSubColVector subR(m_error_klt, shift, 2 * kltPolyCylinder->getCurrentNumberPoints());
      vpSubMatrix subL(m_L_klt, shift, 0, 2 * kltPolyCylinder->getCurrentNumberPoints(), 6);
 
      try {
        kltPolyCylinder->computeInteractionMatrixAndResidu(ctTc0, subR, subL);
      }
      catch (...) {
        throw vpTrackingException(vpTrackingException::fatalError, "Cannot compute interaction matrix");
      }
 
      shift += 2 * kltPolyCylinder->getCurrentNumberPoints();
    }
  }
}
 
void vpMbKltTracker::track(const vpImage<unsigned char> &I)
{
  preTracking(I);
 
  if (m_nbInfos < 4 || m_nbFaceUsed == 0) {
    throw vpTrackingException(vpTrackingException::notEnoughPointError, "Error: not enough features");
  }
 
  computeVVS();
 
  if (postTracking(I, m_w_klt))
    reinit(I);
 
  if (displayFeatures) {
    m_featuresToBeDisplayedKlt = getFeaturesForDisplayKlt();
  }
}
 
void vpMbKltTracker::track(const vpImage<vpRGBa> &I_color)
{
  vpImageConvert::convert(I_color, m_I);
  preTracking(m_I);
 
  if (m_nbInfos < 4 || m_nbFaceUsed == 0) {
    throw vpTrackingException(vpTrackingException::notEnoughPointError, "Error: not enough features");
  }
 
  computeVVS();
 
  if (postTracking(m_I, m_w_klt))
    reinit(m_I);
}
 
void vpMbKltTracker::loadConfigFile(const std::string &configFile, bool verbose)
{
#if defined(VISP_HAVE_PUGIXML)
// Load projection error config
  vpMbTracker::loadConfigFile(configFile, verbose);
 
  vpMbtXmlGenericParser xmlp(vpMbtXmlGenericParser::KLT_PARSER);
  xmlp.setVerbose(verbose);
  xmlp.setKltMaxFeatures(10000);
  xmlp.setKltWindowSize(5);
  xmlp.setKltQuality(0.01);
  xmlp.setKltMinDistance(5);
  xmlp.setKltHarrisParam(0.01);
  xmlp.setKltBlockSize(3);
  xmlp.setKltPyramidLevels(3);
  xmlp.setKltMaskBorder(maskBorder);
  xmlp.setAngleAppear(vpMath::deg(angleAppears));
  xmlp.setAngleDisappear(vpMath::deg(angleDisappears));
 
  try {
    if (verbose) {
      std::cout << " *********** Parsing XML for MBT KLT Tracker ************ " << std::endl;
    }
    xmlp.parse(configFile.c_str());
  }
  catch (...) {
    vpERROR_TRACE("Can't open XML file \"%s\"\n ", configFile.c_str());
    throw vpException(vpException::ioError, "problem to parse configuration file.");
  }
 
  vpCameraParameters camera;
  xmlp.getCameraParameters(camera);
  setCameraParameters(camera);
 
  tracker.setMaxFeatures((int)xmlp.getKltMaxFeatures());
  tracker.setWindowSize((int)xmlp.getKltWindowSize());
  tracker.setQuality(xmlp.getKltQuality());
  tracker.setMinDistance(xmlp.getKltMinDistance());
  tracker.setHarrisFreeParameter(xmlp.getKltHarrisParam());
  tracker.setBlockSize((int)xmlp.getKltBlockSize());
  tracker.setPyramidLevels((int)xmlp.getKltPyramidLevels());
  maskBorder = xmlp.getKltMaskBorder();
  angleAppears = vpMath::rad(xmlp.getAngleAppear());
  angleDisappears = vpMath::rad(xmlp.getAngleDisappear());
 
  // if(useScanLine)
  faces.getMbScanLineRenderer().setMaskBorder(maskBorder);
 
  if (xmlp.hasNearClippingDistance())
    setNearClippingDistance(xmlp.getNearClippingDistance());
 
  if (xmlp.hasFarClippingDistance())
    setFarClippingDistance(xmlp.getFarClippingDistance());
 
  if (xmlp.getFovClipping())
    setClipping(clippingFlag = clippingFlag | vpPolygon3D::FOV_CLIPPING);
 
  useLodGeneral = xmlp.getLodState();
  minLineLengthThresholdGeneral = xmlp.getLodMinLineLengthThreshold();
  minPolygonAreaThresholdGeneral = xmlp.getLodMinPolygonAreaThreshold();
 
  applyLodSettingInConfig = false;
  if (this->getNbPolygon() > 0) {
    applyLodSettingInConfig = true;
    setLod(useLodGeneral);
    setMinLineLengthThresh(minLineLengthThresholdGeneral);
    setMinPolygonAreaThresh(minPolygonAreaThresholdGeneral);
  }
#else
  (void)configFile;
  (void)verbose;
  throw(vpException(vpException::ioError, "vpMbKltTracker::loadConfigFile() needs pugixml built-in 3rdparty"));
#endif
}
 
void vpMbKltTracker::display(const vpImage<unsigned char> &I, const vpHomogeneousMatrix &cMo,
                             const vpCameraParameters &cam, const vpColor &col, unsigned int thickness,
                             bool displayFullModel)
{
  std::vector<std::vector<double> > models =
    vpMbKltTracker::getModelForDisplay(I.getWidth(), I.getHeight(), cMo, cam, displayFullModel);
 
  for (size_t i = 0; i < models.size(); i++) {
    if (vpMath::equal(models[i][0], 0)) {
      vpImagePoint ip1(models[i][1], models[i][2]);
      vpImagePoint ip2(models[i][3], models[i][4]);
      vpDisplay::displayLine(I, ip1, ip2, col, thickness);
    }
    else if (vpMath::equal(models[i][0], 1)) {
      vpImagePoint center(models[i][1], models[i][2]);
      double n20 = models[i][3];
      double n11 = models[i][4];
      double n02 = models[i][5];
      vpDisplay::displayEllipse(I, center, n20, n11, n02, true, col, thickness);
    }
  }
 
  if (displayFeatures) {
    for (size_t i = 0; i < m_featuresToBeDisplayedKlt.size(); i++) {
      if (vpMath::equal(m_featuresToBeDisplayedKlt[i][0], 1)) {
        vpImagePoint ip1(m_featuresToBeDisplayedKlt[i][1], m_featuresToBeDisplayedKlt[i][2]);
        vpDisplay::displayCross(I, ip1, 10, vpColor::red);
 
        vpImagePoint ip2(m_featuresToBeDisplayedKlt[i][3], m_featuresToBeDisplayedKlt[i][4]);
        double id = m_featuresToBeDisplayedKlt[i][5];
        std::stringstream ss;
        ss << id;
        vpDisplay::displayText(I, ip2, ss.str(), vpColor::red);
      }
    }
  }
 
#ifdef VISP_HAVE_OGRE
  if (useOgre)
    faces.displayOgre(cMo);
#endif
}
 
void vpMbKltTracker::display(const vpImage<vpRGBa> &I, const vpHomogeneousMatrix &cMo, const vpCameraParameters &cam,
                             const vpColor &col, unsigned int thickness, bool displayFullModel)
{
  std::vector<std::vector<double> > models =
    vpMbKltTracker::getModelForDisplay(I.getWidth(), I.getHeight(), cMo, cam, displayFullModel);
 
  for (size_t i = 0; i < models.size(); i++) {
    if (vpMath::equal(models[i][0], 0)) {
      vpImagePoint ip1(models[i][1], models[i][2]);
      vpImagePoint ip2(models[i][3], models[i][4]);
      vpDisplay::displayLine(I, ip1, ip2, col, thickness);
    }
    else if (vpMath::equal(models[i][0], 1)) {
      vpImagePoint center(models[i][1], models[i][2]);
      double n20 = models[i][3];
      double n11 = models[i][4];
      double n02 = models[i][5];
      vpDisplay::displayEllipse(I, center, n20, n11, n02, true, col, thickness);
    }
  }
 
  if (displayFeatures) {
    for (size_t i = 0; i < m_featuresToBeDisplayedKlt.size(); i++) {
      if (vpMath::equal(m_featuresToBeDisplayedKlt[i][0], 1)) {
        vpImagePoint ip1(m_featuresToBeDisplayedKlt[i][1], m_featuresToBeDisplayedKlt[i][2]);
        vpDisplay::displayCross(I, ip1, 10, vpColor::red);
 
        vpImagePoint ip2(m_featuresToBeDisplayedKlt[i][3], m_featuresToBeDisplayedKlt[i][4]);
        double id = m_featuresToBeDisplayedKlt[i][5];
        std::stringstream ss;
        ss << id;
        vpDisplay::displayText(I, ip2, ss.str(), vpColor::red);
      }
    }
  }
 
#ifdef VISP_HAVE_OGRE
  if (useOgre)
    faces.displayOgre(cMo);
#endif
}
 
std::vector<std::vector<double> > vpMbKltTracker::getFeaturesForDisplayKlt()
{
  std::vector<std::vector<double> > features;
 
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
 
    if (kltpoly->hasEnoughPoints() && kltpoly->polygon->isVisible() && kltpoly->isTracked()) {
      std::vector<std::vector<double> > currentFeatures = kltpoly->getFeaturesForDisplay();
      features.insert(features.end(), currentFeatures.begin(), currentFeatures.end());
    }
  }
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
 
    if (kltPolyCylinder->isTracked() && kltPolyCylinder->hasEnoughPoints()) {
      std::vector<std::vector<double> > currentFeatures = kltPolyCylinder->getFeaturesForDisplay();
      features.insert(features.end(), currentFeatures.begin(), currentFeatures.end());
    }
  }
 
  return features;
}
 
std::vector<std::vector<double> > vpMbKltTracker::getModelForDisplay(unsigned int width, unsigned int height,
                                                                     const vpHomogeneousMatrix &cMo,
                                                                     const vpCameraParameters &cam,
                                                                     bool displayFullModel)
{
  std::vector<std::vector<double> > models;
 
  vpCameraParameters c = cam;
 
  if (clippingFlag > 3) // Contains at least one FOV constraint
    c.computeFov(width, height);
 
  //  vpMbtDistanceKltPoints *kltpoly;
  //  vpMbtDistanceKltCylinder *kltPolyCylinder;
 
  // Previous version 12/08/2015
  //  for(std::list<vpMbtDistanceKltPoints*>::const_iterator
  //  it=kltPolygons.begin(); it!=kltPolygons.end(); ++it){
  //    kltpoly = *it;
  //    kltpoly->polygon->changeFrame(cMo_);
  //    kltpoly->polygon->computePolygonClipped(c);
  //  }
  faces.computeClippedPolygons(cMo, c);
 
  if (useScanLine && !displayFullModel)
    faces.computeScanLineRender(m_cam, width, height);
 
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    std::vector<std::vector<double> > modelLines = kltpoly->getModelForDisplay(cam, displayFullModel);
    models.insert(models.end(), modelLines.begin(), modelLines.end());
  }
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
    std::vector<std::vector<double> > modelLines = kltPolyCylinder->getModelForDisplay(cMo, cam);
    models.insert(models.end(), modelLines.begin(), modelLines.end());
  }
 
  for (std::list<vpMbtDistanceCircle *>::const_iterator it = circles_disp.begin(); it != circles_disp.end(); ++it) {
    vpMbtDistanceCircle *displayCircle = *it;
    std::vector<double> paramsCircle = displayCircle->getModelForDisplay(cMo, cam, displayFullModel);
    if (!paramsCircle.empty()) {
      models.push_back(paramsCircle);
    }
  }
 
  return models;
}
 
void vpMbKltTracker::testTracking()
{
  unsigned int nbTotalPoints = 0;
  //  for (unsigned int i = 0; i < faces.size(); i += 1){
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    if (kltpoly->polygon->isVisible() && kltpoly->isTracked() && kltpoly->polygon->getNbPoint() > 2 &&
        kltpoly->hasEnoughPoints()) {
      nbTotalPoints += kltpoly->getCurrentNumberPoints();
    }
  }
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
    if (kltPolyCylinder->isTracked() && kltPolyCylinder->hasEnoughPoints())
      nbTotalPoints += kltPolyCylinder->getCurrentNumberPoints();
  }
 
  if (nbTotalPoints < 10) {
    std::cerr << "test tracking failed (too few points to realize a good tracking)." << std::endl;
    throw vpTrackingException(vpTrackingException::fatalError,
                              "test tracking failed (too few points to realize a good tracking).");
  }
}
 
void vpMbKltTracker::initCylinder(const vpPoint &p1, const vpPoint &p2, double radius, int idFace,
                                  const std::string & /*name*/)
{
  vpMbtDistanceKltCylinder *kltPoly = new vpMbtDistanceKltCylinder();
  kltPoly->setCameraParameters(m_cam);
 
  kltPoly->buildFrom(p1, p2, radius);
 
  // Add the Cylinder BBox to the list of polygons
  kltPoly->listIndicesCylinderBBox.push_back(idFace + 1);
  kltPoly->listIndicesCylinderBBox.push_back(idFace + 2);
  kltPoly->listIndicesCylinderBBox.push_back(idFace + 3);
  kltPoly->listIndicesCylinderBBox.push_back(idFace + 4);
 
  kltPoly->hiddenface = &faces;
  kltPoly->useScanLine = useScanLine;
  kltCylinders.push_back(kltPoly);
}
 
void vpMbKltTracker::initCircle(const vpPoint &p1, const vpPoint &p2, const vpPoint &p3, double radius, int /*idFace*/,
                                const std::string &name)
{
  addCircle(p1, p2, p3, radius, name);
}
 
void vpMbKltTracker::addCircle(const vpPoint &P1, const vpPoint &P2, const vpPoint &P3, double r,
                               const std::string &name)
{
  bool already_here = false;
 
  //  for(std::list<vpMbtDistanceCircle*>::const_iterator
  //  it=circles_disp.begin(); it!=circles_disp[i].end(); ++it){
  //    ci = *it;
  //    if((samePoint(*(ci->p1),P1) && samePoint(*(ci->p2),P2) &&
  //    samePoint(*(ci->p3),P3)) ||
  //       (samePoint(*(ci->p1),P1) && samePoint(*(ci->p2),P3) &&
  //       samePoint(*(ci->p3),P2)) ){
  //      already_here = (std::fabs(ci->radius - r) <
  //      std::numeric_limits<double>::epsilon() * vpMath::maximum(ci->radius,
  //      r));
  //    }
  //  }
 
  if (!already_here) {
    vpMbtDistanceCircle *ci = new vpMbtDistanceCircle;
 
    ci->setCameraParameters(m_cam);
    ci->setName(name);
    ci->buildFrom(P1, P2, P3, r);
    circles_disp.push_back(ci);
  }
}
 
void vpMbKltTracker::reInitModel(const vpImage<unsigned char> &I, const std::string &cad_name,
                                 const vpHomogeneousMatrix &cMo, bool verbose, const vpHomogeneousMatrix &T)
{
  m_cMo.eye();
 
  firstInitialisation = true;
 
  // delete the Klt Polygon features
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    if (kltpoly != nullptr) {
      delete kltpoly;
    }
    kltpoly = nullptr;
  }
  kltPolygons.clear();
 
  for (std::list<vpMbtDistanceKltCylinder *>::const_iterator it = kltCylinders.begin(); it != kltCylinders.end();
       ++it) {
    vpMbtDistanceKltCylinder *kltPolyCylinder = *it;
    if (kltPolyCylinder != nullptr) {
      delete kltPolyCylinder;
    }
    kltPolyCylinder = nullptr;
  }
  kltCylinders.clear();
 
  // delete the structures used to display circles
  for (std::list<vpMbtDistanceCircle *>::const_iterator it = circles_disp.begin(); it != circles_disp.end(); ++it) {
    vpMbtDistanceCircle *ci = *it;
    if (ci != nullptr) {
      delete ci;
    }
    ci = nullptr;
  }
 
  faces.reset();
 
  loadModel(cad_name, verbose, T);
  initFromPose(I, cMo);
}
 
void vpMbKltTracker::setUseKltTracking(const std::string &name, const bool &useKltTracking)
{
  for (std::list<vpMbtDistanceKltPoints *>::const_iterator it = kltPolygons.begin(); it != kltPolygons.end(); ++it) {
    vpMbtDistanceKltPoints *kltpoly = *it;
    if (kltpoly->polygon->getName() == name) {
      kltpoly->setTracked(useKltTracking);
    }
  }
}
 
#elif !defined(VISP_BUILD_SHARED_LIBS)
// Work around to avoid warning: libvisp_mbt.a(vpMbKltTracker.cpp.o) has no symbols
void dummy_vpMbKltTracker() { };
#endif // VISP_HAVE_OPENCV