vpMbtDistanceKltCylinder.cpp

/****************************************************************************
 *
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2019 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 http://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:
 * Klt cylinder, containing points of interest.
 *
 * Authors:
 * Aurelien Yol
 *
 *****************************************************************************/

#include <visp3/core/vpPolygon.h>
#include <visp3/mbt/vpMbtDistanceKltCylinder.h>
#include <visp3/mbt/vpMbtDistanceKltPoints.h>

#if defined(VISP_HAVE_MODULE_KLT) && (defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100))

#if defined(VISP_HAVE_CLIPPER)
#include <clipper.hpp> // clipper private library
#endif

#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

vpMbtDistanceKltCylinder::vpMbtDistanceKltCylinder()
  : c0Mo(), p1Ext(), p2Ext(), cylinder(), circle1(), circle2(), initPoints(), initPoints3D(), curPoints(),
    curPointsInd(), nbPointsCur(0), nbPointsInit(0), minNbPoint(4), enoughPoints(false), cam(),
    isTrackedKltCylinder(true), listIndicesCylinderBBox(), hiddenface(NULL), useScanLine(false)
{
}

vpMbtDistanceKltCylinder::~vpMbtDistanceKltCylinder() {}

void vpMbtDistanceKltCylinder::buildFrom(const vpPoint &p1, const vpPoint &p2, const double &r)
{
  p1Ext = p1;
  p2Ext = p2;

  vpColVector ABC(3);
  vpColVector V1(3);
  vpColVector V2(3);

  V1[0] = p1.get_oX();
  V1[1] = p1.get_oY();
  V1[2] = p1.get_oZ();
  V2[0] = p2.get_oX();
  V2[1] = p2.get_oY();
  V2[2] = p2.get_oZ();

  // Get the axis of the cylinder
  ABC = V1 - V2;

  // Build our extremity circles
  circle1.setWorldCoordinates(ABC[0], ABC[1], ABC[2], p1.get_oX(), p1.get_oY(), p1.get_oZ(), r);
  circle2.setWorldCoordinates(ABC[0], ABC[1], ABC[2], p2.get_oX(), p2.get_oY(), p2.get_oZ(), r);

  // Build our cylinder
  cylinder.setWorldCoordinates(ABC[0], ABC[1], ABC[2], (p1.get_oX() + p2.get_oX()) / 2.0,
                               (p1.get_oY() + p2.get_oY()) / 2.0, (p1.get_oZ() + p2.get_oZ()) / 2.0, r);
}

void vpMbtDistanceKltCylinder::init(const vpKltOpencv &_tracker, const vpHomogeneousMatrix &cMo)
{
  c0Mo = cMo;
  cylinder.changeFrame(cMo);

  // extract ids of the points in the face
  nbPointsInit = 0;
  nbPointsCur = 0;
  initPoints = std::map<int, vpImagePoint>();
  initPoints3D = std::map<int, vpPoint>();
  curPoints = std::map<int, vpImagePoint>();
  curPointsInd = std::map<int, int>();

  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);

    bool add = false;

    if (useScanLine) {
      if ((unsigned int)y_tmp < hiddenface->getMbScanLineRenderer().getPrimitiveIDs().getHeight() &&
          (unsigned int)x_tmp < hiddenface->getMbScanLineRenderer().getPrimitiveIDs().getWidth()) {
        for (unsigned int kc = 0; kc < listIndicesCylinderBBox.size(); kc++)
          if (hiddenface->getMbScanLineRenderer().getPrimitiveIDs()[(unsigned int)y_tmp][(unsigned int)x_tmp] ==
              listIndicesCylinderBBox[kc]) {
            add = true;
            break;
          }
      }
    } else {
      std::vector<vpImagePoint> roi;
      for (unsigned int kc = 0; kc < listIndicesCylinderBBox.size(); kc++) {
        hiddenface->getPolygon()[(size_t)listIndicesCylinderBBox[kc]]->getRoiClipped(cam, roi);
        if (vpPolygon::isInside(roi, y_tmp, x_tmp)) {
          add = true;
          break;
        }
        roi.clear();
      }
    }

    if (add) {

      double xm = 0, ym = 0;
      vpPixelMeterConversion::convertPoint(cam, x_tmp, y_tmp, xm, ym);
      double Z = computeZ(xm, ym);
      if (!vpMath::isNaN(Z)) {
#if TARGET_OS_IPHONE
        initPoints[(int)id] = vpImagePoint(y_tmp, x_tmp);
        curPoints[(int)id] = vpImagePoint(y_tmp, x_tmp);
        curPointsInd[(int)id] = (int)i;
#else
        initPoints[id] = vpImagePoint(y_tmp, x_tmp);
        curPoints[id] = vpImagePoint(y_tmp, x_tmp);
        curPointsInd[id] = (int)i;
#endif
        nbPointsInit++;
        nbPointsCur++;

        vpPoint p;
        p.setWorldCoordinates(xm * Z, ym * Z, Z);
#if TARGET_OS_IPHONE
        initPoints3D[(int)id] = p;
#else
        initPoints3D[id] = p;
#endif
        // std::cout << "Computed Z for : " << xm << "," << ym << " : " <<
        // computeZ(xm,ym) << std::endl;
      }
    }
  }

  if (nbPointsCur >= minNbPoint)
    enoughPoints = true;
  else
    enoughPoints = false;

  // std::cout << "Nb detected points in cylinder : " << nbPointsCur <<
  // std::endl;
}

unsigned int vpMbtDistanceKltCylinder::computeNbDetectedCurrent(const vpKltOpencv &_tracker)
{
  long id;
  float x, y;
  nbPointsCur = 0;
  curPoints = std::map<int, vpImagePoint>();
  curPointsInd = std::map<int, int>();

  for (unsigned int i = 0; i < static_cast<unsigned int>(_tracker.getNbFeatures()); i++) {
    _tracker.getFeature((int)i, id, x, y);
    if (isTrackedFeature((int)id)) {
#if TARGET_OS_IPHONE
      curPoints[(int)id] = vpImagePoint(static_cast<double>(y), static_cast<double>(x));
      curPointsInd[(int)id] = (int)i;
#else
      curPoints[id] = vpImagePoint(static_cast<double>(y), static_cast<double>(x));
      curPointsInd[id] = (int)i;
#endif
      nbPointsCur++;
    }
  }

  if (nbPointsCur >= minNbPoint)
    enoughPoints = true;
  else
    enoughPoints = false;

  return nbPointsCur;
}

void vpMbtDistanceKltCylinder::removeOutliers(const vpColVector &_w, const double &threshold_outlier)
{
  std::map<int, vpImagePoint> tmp;
  std::map<int, int> tmp2;
  unsigned int nbSupp = 0;
  unsigned int k = 0;

  nbPointsCur = 0;
  std::map<int, vpImagePoint>::const_iterator iter = curPoints.begin();
  for (; iter != curPoints.end(); ++iter) {
    if (_w[k] > threshold_outlier && _w[k + 1] > threshold_outlier) {
      //     if(_w[k] > threshold_outlier || _w[k+1] > threshold_outlier){
      tmp[iter->first] = vpImagePoint(iter->second.get_i(), iter->second.get_j());
      tmp2[iter->first] = curPointsInd[iter->first];
      nbPointsCur++;
    } else {
      nbSupp++;
      initPoints.erase(iter->first);
    }

    k += 2;
  }

  if (nbSupp != 0) {
    curPoints = std::map<int, vpImagePoint>();
    curPointsInd = std::map<int, int>();

    curPoints = tmp;
    curPointsInd = tmp2;
    if (nbPointsCur >= minNbPoint)
      enoughPoints = true;
    else
      enoughPoints = false;
  }
}

void vpMbtDistanceKltCylinder::computeInteractionMatrixAndResidu(const vpHomogeneousMatrix &_cMc0, vpColVector &_R,
                                                                 vpMatrix &_J)
{
  unsigned int index_ = 0;

  cylinder.changeFrame(_cMc0 * c0Mo);

  std::map<int, vpImagePoint>::const_iterator iter = curPoints.begin();
  for (; iter != curPoints.end(); ++iter) {
    int id(iter->first);
    double i_cur(iter->second.get_i()), j_cur(iter->second.get_j());

    double x_cur(0), y_cur(0);
    vpPixelMeterConversion::convertPoint(cam, j_cur, i_cur, x_cur, y_cur);

    vpPoint p0 = initPoints3D[id];
    p0.changeFrame(_cMc0);
    p0.project();

    double x0_transform(p0.get_x()), y0_transform(p0.get_y());

    double Z = computeZ(x_cur, y_cur);

    if (vpMath::isNaN(Z) || Z < std::numeric_limits<double>::epsilon()) {
      //      std::cout << "Z is Nan : " << A << " , " << B << " , " << C << "
      //      | " << Z << " | " << x_cur << " , " << y_cur << std::endl;
      //      std::cout << std::sqrt(B*B - A*C) << " , " << B*B - A*C <<
      //      std::endl;

      _J[2 * index_][0] = 0;
      _J[2 * index_][1] = 0;
      _J[2 * index_][2] = 0;
      _J[2 * index_][3] = 0;
      _J[2 * index_][4] = 0;
      _J[2 * index_][5] = 0;

      _J[2 * index_ + 1][0] = 0;
      _J[2 * index_ + 1][1] = 0;
      _J[2 * index_ + 1][2] = 0;
      _J[2 * index_ + 1][3] = 0;
      _J[2 * index_ + 1][4] = 0;
      _J[2 * index_ + 1][5] = 0;

      _R[2 * index_] = (x0_transform - x_cur);
      _R[2 * index_ + 1] = (y0_transform - y_cur);
      index_++;
    } else {
      double invZ = 1.0 / Z;

      _J[2 * index_][0] = -invZ;
      _J[2 * index_][1] = 0;
      _J[2 * index_][2] = x_cur * invZ;
      _J[2 * index_][3] = x_cur * y_cur;
      _J[2 * index_][4] = -(1 + x_cur * x_cur);
      _J[2 * index_][5] = y_cur;

      _J[2 * index_ + 1][0] = 0;
      _J[2 * index_ + 1][1] = -invZ;
      _J[2 * index_ + 1][2] = y_cur * invZ;
      _J[2 * index_ + 1][3] = (1 + y_cur * y_cur);
      _J[2 * index_ + 1][4] = -y_cur * x_cur;
      _J[2 * index_ + 1][5] = -x_cur;

      _R[2 * index_] = (x0_transform - x_cur);
      _R[2 * index_ + 1] = (y0_transform - y_cur);
      index_++;
    }
  }
}

bool vpMbtDistanceKltCylinder::isTrackedFeature(int _id)
{
  std::map<int, vpImagePoint>::iterator iter = initPoints.find(_id);
  if (iter != initPoints.end())
    return true;

  return false;
}

void vpMbtDistanceKltCylinder::updateMask(
#if (VISP_HAVE_OPENCV_VERSION >= 0x020408)
    cv::Mat &mask,
#else
    IplImage *mask,
#endif
    unsigned char nb, unsigned int shiftBorder)
{
#if (VISP_HAVE_OPENCV_VERSION >= 0x020408)
  int width = mask.cols;
  int height = mask.rows;
#else
  int width = mask->width;
  int height = mask->height;
#endif

  for (unsigned int kc = 0; kc < listIndicesCylinderBBox.size(); kc++) {
    if ((*hiddenface)[(unsigned int)listIndicesCylinderBBox[kc]]->isVisible() &&
        (*hiddenface)[(unsigned int)listIndicesCylinderBBox[kc]]->getNbPoint() > 2) {
      int i_min, i_max, j_min, j_max;
      std::vector<vpImagePoint> roi;
      (*hiddenface)[(unsigned int)listIndicesCylinderBBox[kc]]->getRoiClipped(cam, roi);

      double shiftBorder_d = (double)shiftBorder;
#if defined(VISP_HAVE_CLIPPER)
      std::vector<vpImagePoint> roi_offset;

      ClipperLib::Path path;
      for (std::vector<vpImagePoint>::const_iterator it = roi.begin(); it != roi.end(); ++it) {
        path.push_back(ClipperLib::IntPoint((ClipperLib::cInt)it->get_u(), (ClipperLib::cInt)it->get_v()));
      }

      ClipperLib::Paths solution;
      ClipperLib::ClipperOffset co;
      co.AddPath(path, ClipperLib::jtRound, ClipperLib::etClosedPolygon);
      co.Execute(solution, -shiftBorder_d);

      // Keep biggest polygon by area
      if (!solution.empty()) {
        size_t index_max = 0;

        if (solution.size() > 1) {
          double max_area = 0;
          vpPolygon polygon_area;

          for (size_t i = 0; i < solution.size(); i++) {
            std::vector<vpImagePoint> corners;

            for (size_t j = 0; j < solution[i].size(); j++) {
              corners.push_back(vpImagePoint((double)(solution[i][j].Y), (double)(solution[i][j].X)));
            }

            polygon_area.buildFrom(corners);
            if (polygon_area.getArea() > max_area) {
              max_area = polygon_area.getArea();
              index_max = i;
            }
          }
        }

        for (size_t i = 0; i < solution[index_max].size(); i++) {
          roi_offset.push_back(vpImagePoint((double)(solution[index_max][i].Y), (double)(solution[index_max][i].X)));
        }
      } else {
        roi_offset = roi;
      }

      vpPolygon polygon_test(roi_offset);
      vpImagePoint imPt;
#endif

#if defined(VISP_HAVE_CLIPPER)
      vpPolygon3D::getMinMaxRoi(roi_offset, i_min, i_max, j_min, j_max);
#else
      vpPolygon3D::getMinMaxRoi(roi, i_min, i_max, j_min, j_max);
#endif

      /* check image boundaries */
      if (i_min > height) { // underflow
        i_min = 0;
      }
      if (i_max > height) {
        i_max = height;
      }
      if (j_min > width) { // underflow
        j_min = 0;
      }
      if (j_max > width) {
        j_max = width;
      }

#if (VISP_HAVE_OPENCV_VERSION >= 0x020408)
      for (int i = i_min; i < i_max; i++) {
        double i_d = (double)i;

        for (int j = j_min; j < j_max; j++) {
          double j_d = (double)j;

#if defined(VISP_HAVE_CLIPPER)
          imPt.set_ij(i_d, j_d);
          if (polygon_test.isInside(imPt)) {
            mask.ptr<uchar>(i)[j] = nb;
          }
#else
          if (shiftBorder != 0) {
            if (vpPolygon::isInside(roi, i_d, j_d) &&
                vpPolygon::isInside(roi, i_d + shiftBorder_d, j_d + shiftBorder_d) &&
                vpPolygon::isInside(roi, i_d - shiftBorder_d, j_d + shiftBorder_d) &&
                vpPolygon::isInside(roi, i_d + shiftBorder_d, j_d - shiftBorder_d) &&
                vpPolygon::isInside(roi, i_d - shiftBorder_d, j_d - shiftBorder_d)) {
              mask.at<unsigned char>(i, j) = nb;
            }
          } else {
            if (vpPolygon::isInside(roi, i, j)) {
              mask.at<unsigned char>(i, j) = nb;
            }
          }
#endif
        }
      }
#else
      unsigned char *ptrData = (unsigned char *)mask->imageData + i_min * mask->widthStep + j_min;
      for (int i = i_min; i < i_max; i++) {
        double i_d = (double)i;
        for (int j = j_min; j < j_max; j++) {
          double j_d = (double)j;
          if (shiftBorder != 0) {
            if (vpPolygon::isInside(roi, i_d, j_d) &&
                vpPolygon::isInside(roi, i_d + shiftBorder_d, j_d + shiftBorder_d) &&
                vpPolygon::isInside(roi, i_d - shiftBorder_d, j_d + shiftBorder_d) &&
                vpPolygon::isInside(roi, i_d + shiftBorder_d, j_d - shiftBorder_d) &&
                vpPolygon::isInside(roi, i_d - shiftBorder_d, j_d - shiftBorder_d)) {
              *(ptrData++) = nb;
            } else {
              ptrData++;
            }
          } else {
            if (vpPolygon::isInside(roi, i, j)) {
              *(ptrData++) = nb;
            } else {
              ptrData++;
            }
          }
        }
        ptrData += mask->widthStep - j_max + j_min;
      }
#endif
    }
  }
}

void vpMbtDistanceKltCylinder::displayPrimitive(const vpImage<unsigned char> &_I)
{
  std::map<int, vpImagePoint>::const_iterator iter = curPoints.begin();
  for (; iter != curPoints.end(); ++iter) {
    int id(iter->first);
    vpImagePoint iP;
    iP.set_i(static_cast<double>(iter->second.get_i()));
    iP.set_j(static_cast<double>(iter->second.get_j()));

    vpDisplay::displayCross(_I, iP, 10, vpColor::red);

    iP.set_i(vpMath::round(iP.get_i() + 7));
    iP.set_j(vpMath::round(iP.get_j() + 7));
    std::stringstream ss;
    ss << id;
    vpDisplay::displayText(_I, iP, ss.str(), vpColor::red);
  }
}

void vpMbtDistanceKltCylinder::displayPrimitive(const vpImage<vpRGBa> &_I)
{
  std::map<int, vpImagePoint>::const_iterator iter = curPoints.begin();
  for (; iter != curPoints.end(); ++iter) {
    int id(iter->first);
    vpImagePoint iP;
    iP.set_i(static_cast<double>(iter->second.get_i()));
    iP.set_j(static_cast<double>(iter->second.get_j()));

    vpDisplay::displayCross(_I, iP, 10, vpColor::red);

    iP.set_i(vpMath::round(iP.get_i() + 7));
    iP.set_j(vpMath::round(iP.get_j() + 7));
    std::stringstream ss;
    ss << id;
    vpDisplay::displayText(_I, iP, ss.str(), vpColor::red);
  }
}

void vpMbtDistanceKltCylinder::display(const vpImage<unsigned char> &I, const vpHomogeneousMatrix &cMo,
                                       const vpCameraParameters &camera, const vpColor &col,
                                       unsigned int thickness, const bool /*displayFullModel*/)
{
  std::vector<std::vector<double> > models = getModelForDisplay(cMo, camera);

  for (size_t i = 0; i < models.size(); i++) {
    vpImagePoint ip1(models[i][1], models[i][2]);
    vpImagePoint ip2(models[i][3], models[i][4]);
    vpDisplay::displayLine(I, ip1, ip2, col, thickness);
  }
}

void vpMbtDistanceKltCylinder::display(const vpImage<vpRGBa> &I, const vpHomogeneousMatrix &cMo,
                                       const vpCameraParameters &camera, const vpColor &col,
                                       unsigned int thickness, const bool /*displayFullModel*/)
{
  std::vector<std::vector<double> > models = getModelForDisplay(cMo, camera);

  for (size_t i = 0; i < models.size(); i++) {
    vpImagePoint ip1(models[i][1], models[i][2]);
    vpImagePoint ip2(models[i][3], models[i][4]);

    vpDisplay::displayLine(I, ip1, ip2, col, thickness);
  }
}

std::vector<std::vector<double> > vpMbtDistanceKltCylinder::getFeaturesForDisplay()
{
  std::vector<std::vector<double> > features;

  std::map<int, vpImagePoint>::const_iterator iter = curPoints.begin();
  for (; iter != curPoints.end(); ++iter) {
    int id(iter->first);
    vpImagePoint iP;
    iP.set_i(static_cast<double>(iter->second.get_i()));
    iP.set_j(static_cast<double>(iter->second.get_j()));

    vpImagePoint iP2;
    iP2.set_i(vpMath::round(iP.get_i() + 7));
    iP2.set_j(vpMath::round(iP.get_j() + 7));

#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
    std::vector<double> params = {1, //KLT
                                  iP.get_i(),
                                  iP.get_j(),
                                  iP2.get_i(),
                                  iP2.get_j(),
                                  static_cast<double>(id)};
#else
    std::vector<double> params;
    params.push_back(1); //KLT
    params.push_back(iP.get_i());
    params.push_back(iP.get_j());
    params.push_back(iP2.get_i());
    params.push_back(iP2.get_j());
    params.push_back(static_cast<double>(id));
#endif
    features.push_back(params);
  }

  return features;
}

std::vector<std::vector<double> > vpMbtDistanceKltCylinder::getModelForDisplay(const vpHomogeneousMatrix &cMo,
                                                                               const vpCameraParameters &camera)
{
  std::vector<std::vector<double> > models;

  // if(isvisible || displayFullModel)
  {
    // Perspective projection
    circle1.changeFrame(cMo);
    circle2.changeFrame(cMo);
    cylinder.changeFrame(cMo);

    try {
      circle1.projection();
    } catch (...) {
      std::cout << "Problem projection circle 1";
    }
    try {
      circle2.projection();
    } catch (...) {
      std::cout << "Problem projection circle 2";
    }

    cylinder.projection();

    double rho1, theta1;
    double rho2, theta2;

    // Meters to pixels conversion
    vpMeterPixelConversion::convertLine(camera, cylinder.getRho1(), cylinder.getTheta1(), rho1, theta1);
    vpMeterPixelConversion::convertLine(camera, cylinder.getRho2(), cylinder.getTheta2(), rho2, theta2);

    // Determine intersections between circles and limbos
    double i11, i12, i21, i22, j11, j12, j21, j22;

    vpCircle::computeIntersectionPoint(circle1, camera, rho1, theta1, i11, j11);
    vpCircle::computeIntersectionPoint(circle2, camera, rho1, theta1, i12, j12);

    vpCircle::computeIntersectionPoint(circle1, camera, rho2, theta2, i21, j21);
    vpCircle::computeIntersectionPoint(circle2, camera, rho2, theta2, i22, j22);

    // Create the image points
    vpImagePoint ip11, ip12, ip21, ip22;
    ip11.set_ij(i11, j11);
    ip12.set_ij(i12, j12);
    ip21.set_ij(i21, j21);
    ip22.set_ij(i22, j22);

#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
    std::vector<double> params1 = {0, //line parameters
                                   ip11.get_i(),
                                   ip11.get_j(),
                                   ip12.get_i(),
                                   ip12.get_j()};
    models.push_back(params1);

    std::vector<double> params2 = {0, //line parameters
                                   ip21.get_i(),
                                   ip21.get_j(),
                                   ip22.get_i(),
                                   ip22.get_j()};
#else
    std::vector<double> params1, params2;
    params1.push_back(0); //line parameters
    params1.push_back(ip11.get_i());
    params1.push_back(ip11.get_j());
    params1.push_back(ip12.get_i());
    params1.push_back(ip12.get_j());

    params2.push_back(0); //line parameters
    params2.push_back(ip21.get_i());
    params2.push_back(ip21.get_j());
    params2.push_back(ip22.get_i());
    params2.push_back(ip22.get_j());
#endif
    models.push_back(params1);
    models.push_back(params2);
  }

  return models;
}

// ######################
//   Private Functions
// ######################

double vpMbtDistanceKltCylinder::computeZ(const double &x, const double &y)
{
  //  double A = x*x + y*y + 1 -
  //  ((cylinder.getA()*x+cylinder.getB()*y+cylinder.getC()) *
  //  (cylinder.getA()*x+cylinder.getB()*y+cylinder.getC())); double B = (x *
  //  cylinder.getX() + y * cylinder.getY() + cylinder.getZ()); double C =
  //  cylinder.getX() * cylinder.getX() + cylinder.getY() * cylinder.getY() +
  //  cylinder.getZ() * cylinder.getZ() - cylinder.getR() * cylinder.getR();
  //
  //  return (B - std::sqrt(B*B - A*C))/A;

  return cylinder.computeZ(x, y);
}
#elif !defined(VISP_BUILD_SHARED_LIBS)
// Work arround to avoid warning:
// libvisp_mbt.a(vpMbtDistanceKltCylinder.cpp.o) has no symbols
void dummy_vpMbtDistanceKltCylinder(){};
#endif