vpPoseDementhon.cpp

/*
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2023 by Inria. All rights reserved.
 *
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 * 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.
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 * For using ViSP with software that can not be combined with the GNU
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 * 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
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 *
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 *
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 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * Pose computation.
 */
 
#include <visp3/core/vpMath.h>
#include <visp3/vision/vpPose.h>
 
#define DEBUG_LEVEL1 0
#define DEBUG_LEVEL2 0
#define DEBUG_LEVEL3 0
 
#define SEUIL_RESIDUAL 0.0001 /* avant 0.01 dans while du calculArbreDementhon */
#define EPS_DEM 0.001
 
#define ITER_MAX 30 /* max number of iterations for Demonthon's loop */
 
static void calculSolutionDementhon(vpColVector &I4, vpColVector &J4, vpHomogeneousMatrix &cMo)
{
 
#if (DEBUG_LEVEL1)
  std::cout << "begin (Dementhon.cc)CalculSolutionDementhon() " << std::endl;
#endif
 
  // norm of the 3 first components of I4 and J4
  double normI3 = sqrt((I4[0] * I4[0]) + (I4[1] * I4[1]) + (I4[2] * I4[2]));
  double normJ3 = sqrt((J4[0] * J4[0]) + (J4[1] * J4[1]) + (J4[2] * J4[2]));
 
  if ((normI3 < 1e-10) || (normJ3 < 1e-10)) {
    // vpERROR_TRACE(" normI+normJ = 0, division par zero " ) ;
    throw(vpException(vpException::divideByZeroError,
                      "Division by zero in Dementhon pose computation: normI or normJ = 0"));
  }
 
  double Z0 = 2.0 / (normI3 + normJ3);
 
  vpColVector I3(3), J3(3), K3(3);
  for (unsigned int i = 0; i < 3; ++i) {
    I3[i] = I4[i] / normI3;
    J3[i] = J4[i] / normJ3;
  }
 
  K3 = vpColVector::cross(I3, J3); // k = I x J
  K3.normalize();
 
  J3 = vpColVector::cross(K3, I3);
 
  // calcul de la matrice de passage
  cMo[0][0] = I3[0];
  cMo[0][1] = I3[1];
  cMo[0][2] = I3[2];
  cMo[0][3] = I4[3] * Z0;
 
  cMo[1][0] = J3[0];
  cMo[1][1] = J3[1];
  cMo[1][2] = J3[2];
  cMo[1][3] = J4[3] * Z0;
 
  cMo[2][0] = K3[0];
  cMo[2][1] = K3[1];
  cMo[2][2] = K3[2];
  cMo[2][3] = Z0;
 
#if (DEBUG_LEVEL1)
  std::cout << "end (Dementhon.cc)CalculSolutionDementhon() " << std::endl;
#endif
}
 
void vpPose::poseDementhonNonPlan(vpHomogeneousMatrix &cMo)
{
  vpPoint P;
  double cdg[3];
  /* compute the cog of the 3D points */
  cdg[0] = 0.0;
  cdg[1] = 0.0;
  cdg[2] = 0.0;
  for (std::list<vpPoint>::const_iterator it = listP.begin(); it != listP.end(); ++it) {
    P = (*it);
    cdg[0] += P.get_oX();
    cdg[1] += P.get_oY();
    cdg[2] += P.get_oZ();
  }
  for (unsigned int i = 0; i < 3; ++i) {
    cdg[i] /= npt;
  }
  // --comment: print cdg cdg of 0 cdg of 1 cdg of 2
 
  c3d.clear();
  /* translate the 3D points wrt cog */
  for (std::list<vpPoint>::const_iterator it = listP.begin(); it != listP.end(); ++it) {
    P = (*it);
    P.set_oX(P.get_oX() - cdg[0]);
    P.set_oY(P.get_oY() - cdg[1]);
    P.set_oZ(P.get_oZ() - cdg[2]);
    c3d.push_back(P);
  }
 
  vpMatrix A(npt, 4), Ap;
 
  for (unsigned int i = 0; i < npt; ++i) {
    A[i][0] = c3d[i].get_oX();
    A[i][1] = c3d[i].get_oY();
    A[i][2] = c3d[i].get_oZ();
    A[i][3] = 1.0;
  }
  Ap = A.pseudoInverse(m_dementhonSvThresh);
 
#if (DEBUG_LEVEL2)
  {
    std::cout << "A" << std::endl << A << std::endl;
    std::cout << "A^+" << std::endl << Ap << std::endl;
  }
#endif
 
  vpColVector xprim(npt);
  vpColVector yprim(npt);
 
  for (unsigned int i = 0; i < npt; ++i) {
    xprim[i] = c3d[i].get_x();
    yprim[i] = c3d[i].get_y();
  }
  vpColVector I4(4), J4(4);
 
  I4 = Ap * xprim;
  J4 = Ap * yprim;
 
  calculSolutionDementhon(I4, J4, cMo);
 
  int erreur = 0;
  for (unsigned int i = 0; i < npt; ++i) {
    double z;
    z = (cMo[2][0] * c3d[i].get_oX()) + (cMo[2][1] * c3d[i].get_oY()) + (cMo[2][2] * c3d[i].get_oZ()) + cMo[2][3];
    if (z <= 0.0) {
      erreur = -1;
    }
  }
  if (erreur == -1) {
    throw(vpException(vpException::fatalError, "End of Dementhon since z < 0 for both solutions at the beginning"));
  }
  int cpt = 0;
  double res = sqrt(computeResidualDementhon(cMo) / npt);
  double res_old = 2.0 * res;
 
  // In his paper, Dementhon suggests to use the difference
  // between 2 successive norm of eps. We prefer to use the mean of the
  // residuals in the image
  while ((cpt < ITER_MAX) && (res > SEUIL_RESIDUAL) && (res < res_old)) {
 
    vpHomogeneousMatrix cMo_old;
    res_old = res;
    cMo_old = cMo;
 
    for (unsigned int i = 0; i < npt; ++i) {
      double eps =
        ((cMo[2][0] * c3d[i].get_oX()) + (cMo[2][1] * c3d[i].get_oY()) + (cMo[2][2] * c3d[i].get_oZ())) / cMo[2][3];
 
      xprim[i] = (1.0 + eps) * c3d[i].get_x();
      yprim[i] = (1.0 + eps) * c3d[i].get_y();
    }
    I4 = Ap * xprim;
    J4 = Ap * yprim;
 
    calculSolutionDementhon(I4, J4, cMo);
    res = sqrt(computeResidualDementhon(cMo) / npt);
    for (unsigned int i = 0; i < npt; ++i) {
      double z;
      z = (cMo[2][0] * c3d[i].get_oX()) + (cMo[2][1] * c3d[i].get_oY()) + (cMo[2][2] * c3d[i].get_oZ()) + cMo[2][3];
      if (z <= 0.0) {
        erreur = -1;
      }
    }
    if (erreur == -1) {
      cMo = cMo_old;
      res = res_old; // to leave the while loop
#if (DEBUG_LEVEL3)
      std::cout << "Pb z < 0 with cMo in Dementhon's loop" << std::endl;
#endif
    }
#if (DEBUG_LEVEL3)
    vpThetaUVector erc;
    cMo.extract(erc);
    std::cout << "it = " << cpt << " residu = " << res << " Theta U rotation: " << vpMath::deg(erc[0]) << " "
      << vpMath::deg(erc[1]) << " " << vpMath::deg(erc[2]) << std::endl;
#endif
    if (res > res_old) {
#if (DEBUG_LEVEL3)
      std::cout << "Divergence : res = " << res << " res_old = " << res_old << std::endl;
#endif
      cMo = cMo_old;
    }
    cpt++;
  }
  // go back to the initial frame
  cMo[0][3] -= ((cdg[0] * cMo[0][0]) + (cdg[1] * cMo[0][1]) + (cdg[2] * cMo[0][2]));
  cMo[1][3] -= ((cdg[0] * cMo[1][0]) + (cdg[1] * cMo[1][1]) + (cdg[2] * cMo[1][2]));
  cMo[2][3] -= ((cdg[0] * cMo[2][0]) + (cdg[1] * cMo[2][1]) + (cdg[2] * cMo[2][2]));
}
 
static void calculRTheta(double s, double c, double &r, double &theta)
{
  if ((fabs(c) > EPS_DEM) || (fabs(s) > EPS_DEM)) {
    r = sqrt(sqrt((s * s) + (c * c)));
    theta = atan2(s, c) / 2.0;
  }
  else {
    if (fabs(c) > fabs(s)) {
      r = fabs(c);
      if (c >= 0.0) {
        theta = M_PI / 2;
      }
      else {
        theta = -M_PI / 2;
      }
    }
    else {
      r = fabs(s);
      if (s >= 0.0) {
        theta = M_PI / 4.0;
      }
      else {
        theta = -M_PI / 4.0;
      }
    }
  }
}
 
static void calculTwoSolutionsDementhonPlan(vpColVector &I04, vpColVector &J04, vpColVector &U,
                                            vpHomogeneousMatrix &cMo1, vpHomogeneousMatrix &cMo2)
{
  vpColVector I0(3), J0(3);
  for (unsigned int i = 0; i < 3; ++i) {
    I0[i] = I04[i];
    J0[i] = J04[i];
  }
  double s = -2.0 * vpColVector::dotProd(I0, J0);
  double c = J0.sumSquare() - I0.sumSquare();
 
  double r, theta;
  calculRTheta(s, c, r, theta);
  double co = cos(theta);
  double si = sin(theta);
 
  // calcul de la premiere solution
  vpColVector I(4), J(4);
  I = I04 + (U * r * co);
  J = J04 + (U * r * si);
 
#if (DEBUG_LEVEL2)
  {
    std::cout << "I0 " << I04.t() << std::endl;
    std::cout << "J0 " << J04.t() << std::endl;
    std::cout << "I1 " << I.t() << std::endl;
    std::cout << "J1 " << J.t() << std::endl;
  }
#endif
  calculSolutionDementhon(I, J, cMo1);
 
  // calcul de la deuxieme solution
  I = I04 - (U * r * co);
  J = J04 - (U * r * si);
#if (DEBUG_LEVEL2)
  {
    std::cout << "I2 " << I.t() << std::endl;
    std::cout << "J2 " << J.t() << std::endl;
  }
#endif
  calculSolutionDementhon(I, J, cMo2);
}
 
int vpPose::calculArbreDementhon(vpMatrix &Ap, vpColVector &U, vpHomogeneousMatrix &cMo)
{
#if (DEBUG_LEVEL1)
  std::cout << "begin vpPose::CalculArbreDementhon() " << std::endl;
#endif
 
  int erreur = 0;
 
  // test if all points are in front of the camera
  for (unsigned int i = 0; i < npt; ++i) {
    double z;
    z = (cMo[2][0] * c3d[i].get_oX()) + (cMo[2][1] * c3d[i].get_oY()) + (cMo[2][2] * c3d[i].get_oZ()) + cMo[2][3];
    if (z <= 0.0) {
      erreur = -1;
      return erreur;
    }
  }
 
  unsigned int cpt = 0;
  double res_min = sqrt(computeResidualDementhon(cMo) / npt);
  double res_old = 2.0 * res_min;
 
  /* FC modif SEUIL_RESIDUAL 0.01 a 0.001 */
  while ((cpt < ITER_MAX) && (res_min > SEUIL_RESIDUAL) && (res_min < res_old)) {
    vpHomogeneousMatrix cMo1, cMo2, cMo_old;
 
    res_old = res_min;
    cMo_old = cMo;
 
    vpColVector xprim(npt), yprim(npt);
    for (unsigned int i = 0; i < npt; ++i) {
      double eps =
        ((cMo[2][0] * c3d[i].get_oX()) + (cMo[2][1] * c3d[i].get_oY()) + (cMo[2][2] * c3d[i].get_oZ())) / cMo[2][3];
 
      xprim[i] = (1.0 + eps) * c3d[i].get_x();
      yprim[i] = (1.0 + eps) * c3d[i].get_y();
    }
 
    vpColVector I04(4), J04(4);
    I04 = Ap * xprim;
    J04 = Ap * yprim;
 
    calculTwoSolutionsDementhonPlan(I04, J04, U, cMo1, cMo2);
 
    // test if all points are in front of the camera for cMo1 and cMo2
    int erreur1 = 0;
    int erreur2 = 0;
    for (unsigned int i = 0; i < npt; ++i) {
      double z;
      z = (cMo1[2][0] * c3d[i].get_oX()) + (cMo1[2][1] * c3d[i].get_oY()) + (cMo1[2][2] * c3d[i].get_oZ()) + cMo1[2][3];
      if (z <= 0.0) {
        erreur1 = -1;
      }
      z = (cMo2[2][0] * c3d[i].get_oX()) + (cMo2[2][1] * c3d[i].get_oY()) + (cMo2[2][2] * c3d[i].get_oZ()) + cMo2[2][3];
      if (z <= 0.0) {
        erreur2 = -1;
      }
    }
 
    if ((erreur1 == -1) && (erreur2 == -1)) {
      cMo = cMo_old;
#if (DEBUG_LEVEL3)
      std::cout << " End of loop since z < 0 for both solutions" << std::endl;
#endif
      break; // outside of while due to z < 0
    }
    if ((erreur1 == 0) && (erreur2 == -1)) {
      cMo = cMo1;
      res_min = sqrt(computeResidualDementhon(cMo) / npt);
    }
    if ((erreur1 == -1) && (erreur2 == 0)) {
      cMo = cMo2;
      res_min = sqrt(computeResidualDementhon(cMo) / npt);
    }
    if ((erreur1 == 0) && (erreur2 == 0)) {
      double res1 = sqrt(computeResidualDementhon(cMo1) / npt);
      double res2 = sqrt(computeResidualDementhon(cMo2) / npt);
      if (res1 <= res2) {
        res_min = res1;
        cMo = cMo1;
      }
      else {
        res_min = res2;
        cMo = cMo2;
      }
    }
 
#if (DEBUG_LEVEL3)
    if (erreur1 == 0) {
      double s = sqrt(computeResidualDementhon(cMo1) / npt);
      vpThetaUVector erc;
      cMo1.extract(erc);
      std::cout << "it = " << cpt << " cMo1 : residu: " << s << " Theta U rotation: " << vpMath::deg(erc[0]) << " "
        << vpMath::deg(erc[1]) << " " << vpMath::deg(erc[2]) << std::endl;
    }
    else
      std::cout << "Pb z < 0 with cMo1" << std::endl;
 
    if (erreur2 == 0) {
      double s = sqrt(computeResidualDementhon(cMo2) / npt);
      vpThetaUVector erc;
      cMo2.extract(erc);
      std::cout << "it = " << cpt << " cMo2 : residu: " << s << " Theta U rotation: " << vpMath::deg(erc[0]) << " "
        << vpMath::deg(erc[1]) << " " << vpMath::deg(erc[2]) << std::endl;
    }
    else
      std::cout << "Pb z < 0 with cMo2" << std::endl;
#endif
 
    if (res_min > res_old) {
#if (DEBUG_LEVEL3)
      std::cout << "Divergence : res_min = " << res_min << " res_old = " << res_old << std::endl;
#endif
      cMo = cMo_old;
    }
    cpt++;
  } /* end of while */
 
#if (DEBUG_LEVEL1)
  std::cout << "end vpPose::CalculArbreDementhon() return " << erreur << std::endl;
#endif
 
  return erreur;
}
 
void vpPose::poseDementhonPlan(vpHomogeneousMatrix &cMo)
{
#if (DEBUG_LEVEL1)
  std::cout << "begin CCalculPose::PoseDementhonPlan()" << std::endl;
#endif
  const double svdFactorUsedWhenFailure = 10.; // Factor by which is multipled m_dementhonSvThresh each time the svdDecomposition fails
  const double svdThresholdLimit = 1e-2; // The svd decomposition will be tested with a threshold up to this value. If with this threshold, the rank of A is still !=3, an exception is thrown
  const double lnOfSvdFactorUsed = std::log(svdFactorUsedWhenFailure);
  const double logNOfSvdThresholdLimit = std::log(svdThresholdLimit)/lnOfSvdFactorUsed;
  vpPoint P;
  double cdg[3];
  /* compute the cog of the 3D points */
  cdg[0] = 0.0;
  cdg[1] = 0.0;
  cdg[2] = 0.0;
  for (std::list<vpPoint>::const_iterator it = listP.begin(); it != listP.end(); ++it) {
    P = (*it);
    cdg[0] += P.get_oX();
    cdg[1] += P.get_oY();
    cdg[2] += P.get_oZ();
  }
  for (unsigned int i = 0; i < 3; ++i) {
    cdg[i] /= npt;
  }
  // --comment: print cdg  cdg of 0 of 1 and of 2
 
  c3d.clear();
  /* translate the 3D points wrt cog */
  for (std::list<vpPoint>::const_iterator it = listP.begin(); it != listP.end(); ++it) {
    P = (*it);
    P.set_oX(P.get_oX() - cdg[0]);
    P.set_oY(P.get_oY() - cdg[1]);
    P.set_oZ(P.get_oZ() - cdg[2]);
    c3d.push_back(P);
  }
 
  vpMatrix A(npt, 4);
 
  for (unsigned int i = 0; i < npt; ++i) {
    A[i][0] = c3d[i].get_oX();
    A[i][1] = c3d[i].get_oY();
    A[i][2] = c3d[i].get_oZ();
    A[i][3] = 1.0;
  }
  vpColVector sv;
  vpMatrix Ap, imA, imAt, kAt;
  bool isRankEqualTo3 = false; // Indicates if the rank of A is the expected one
  // Get the log_n(m_dementhonSvThresh), where n is the factor by which we will multiply it if the svd decomposition fails.
  double logNofSvdThresh = std::log(m_dementhonSvThresh)/lnOfSvdFactorUsed;
  // Ensure that if the user chose a threshold > svdThresholdLimit, at least 1 iteration of svd decomposition is performed
  int nbMaxIter = static_cast<int>(std::max<double>(std::ceil(logNOfSvdThresholdLimit - logNofSvdThresh), 1.));
  double svdThreshold = m_dementhonSvThresh;
  int irank = 0;
  for (int i = 0; (i < nbMaxIter) && (!isRankEqualTo3); ++i) {
    irank = A.pseudoInverse(Ap, sv, svdThreshold, imA, imAt, kAt);
    if (irank == 3) {
      isRankEqualTo3 = true;
    }
    else {
      isRankEqualTo3 = false;
      svdThreshold *= svdFactorUsedWhenFailure;
    }
  }
 
  if (!isRankEqualTo3) {
    std::stringstream errorMsg;
    errorMsg << "In Dementhon planar, after ";
    errorMsg << nbMaxIter;
    errorMsg << " trials multiplying the svd threshold by ";
    errorMsg << svdFactorUsedWhenFailure;
    errorMsg << ", rank (";
    errorMsg << irank;
    errorMsg << ") is still not 3";
    throw(vpException(vpException::fatalError, errorMsg.str()));
  }
  // calcul de U
  vpColVector U(4);
  for (unsigned int i = 0; i < 4; ++i) {
    U[i] = kAt[0][i];
  }
#if (DEBUG_LEVEL2)
  {
    std::cout << "A" << std::endl << A << std::endl;
    std::cout << "A^+" << std::endl << Ap << std::endl;
    std::cout << "U^T = " << U.t() << std::endl;
  }
#endif
 
  vpColVector xi(npt);
  vpColVector yi(npt);
 
  for (unsigned int i = 0; i < npt; ++i) {
    xi[i] = c3d[i].get_x();
    yi[i] = c3d[i].get_y();
  }
 
  vpColVector I04(4), J04(4);
  I04 = Ap * xi;
  J04 = Ap * yi;
 
  vpHomogeneousMatrix cMo1, cMo2;
  calculTwoSolutionsDementhonPlan(I04, J04, U, cMo1, cMo2);
 
#if DEBUG_LEVEL3
  double res = sqrt(computeResidualDementhon(cMo1) / npt);
  vpThetaUVector erc;
  cMo1.extract(erc);
  std::cout << "cMo Start Tree 1 : res " << res << " Theta U rotation: " << vpMath::deg(erc[0]) << " "
    << vpMath::deg(erc[1]) << " " << vpMath::deg(erc[2]) << std::endl;
  res = sqrt(computeResidualDementhon(cMo2) / npt);
  cMo2.extract(erc);
  std::cout << "cMo Start Tree 2 : res " << res << " Theta U rotation: " << vpMath::deg(erc[0]) << " "
    << vpMath::deg(erc[1]) << " " << vpMath::deg(erc[2]) << std::endl;
#endif
 
  int erreur1 = calculArbreDementhon(Ap, U, cMo1);
  int erreur2 = calculArbreDementhon(Ap, U, cMo2);
 
  if ((erreur1 == -1) && (erreur2 == -1)) {
    throw(
        vpException(vpException::fatalError, "Error in Dementhon planar: z < 0 with Start Tree 1 and Start Tree 2..."));
  }
  if ((erreur1 == 0) && (erreur2 == -1)) {
    cMo = cMo1;
  }
  if ((erreur1 == -1) && (erreur2 == 0)) {
    cMo = cMo2;
  }
  if ((erreur1 == 0) && (erreur2 == 0)) {
    double s1 = computeResidualDementhon(cMo1);
    double s2 = computeResidualDementhon(cMo2);
 
    if (s1 <= s2) {
      cMo = cMo1;
    }
    else {
      cMo = cMo2;
    }
 
#if DEBUG_LEVEL3
    if (erreur1 == -1)
      std::cout << "Pb z < 0 with Start Tree 1" << std::endl;
    if (erreur2 == -1)
      std::cout << "Pb z < 0 with Start Tree 2" << std::endl;
    if (s1 <= s2)
      std::cout << " Tree 1 chosen  " << std::endl;
    else
      std::cout << " Tree 2 chosen  " << std::endl;
#endif
  }
 
  cMo[0][3] -= ((cdg[0] * cMo[0][0]) + (cdg[1] * cMo[0][1]) + (cdg[2] * cMo[0][2]));
  cMo[1][3] -= ((cdg[0] * cMo[1][0]) + (cdg[1] * cMo[1][1]) + (cdg[2] * cMo[1][2]));
  cMo[2][3] -= ((cdg[0] * cMo[2][0]) + (cdg[1] * cMo[2][1]) + (cdg[2] * cMo[2][2]));
 
#if (DEBUG_LEVEL1)
  std::cout << "end CCalculPose::PoseDementhonPlan()" << std::endl;
#endif
}
 
double vpPose::computeResidualDementhon(const vpHomogeneousMatrix &cMo)
{
  double squared_error = 0;
 
  // Be careful: since c3d has been translated so that point0 is at the cdg,
  // cMo here corresponds to object frame at that point, i.e, only the one used
  // internally to Dementhon's method
 
  for (unsigned int i = 0; i < npt; ++i) {
 
    double X = (c3d[i].get_oX() * cMo[0][0]) + (c3d[i].get_oY() * cMo[0][1]) + (c3d[i].get_oZ() * cMo[0][2]) + cMo[0][3];
    double Y = (c3d[i].get_oX() * cMo[1][0]) + (c3d[i].get_oY() * cMo[1][1]) + (c3d[i].get_oZ() * cMo[1][2]) + cMo[1][3];
    double Z = (c3d[i].get_oX() * cMo[2][0]) + (c3d[i].get_oY() * cMo[2][1]) + (c3d[i].get_oZ() * cMo[2][2]) + cMo[2][3];
 
    double x = X / Z;
    double y = Y / Z;
 
    squared_error += vpMath::sqr(x - c3d[i].get_x()) + vpMath::sqr(y - c3d[i].get_y());
  }
  return squared_error;
}
 
#undef EPS_DEM
#undef SEUIL_RESIDUAL
#undef ITER_MAX
#undef DEBUG_LEVEL1
#undef DEBUG_LEVEL2
#undef DEBUG_LEVEL3