vpMomentAlpha.cpp

/****************************************************************************
 *
 * $Id: vpMomentAlpha.cpp 4056 2013-01-05 13:04:42Z fspindle $
 *
 * This file is part of the ViSP software.
 * Copyright (C) 2005 - 2013 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
 * ("GPL") version 2 as published by the Free Software Foundation.
 * 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://www.irisa.fr/lagadic/visp/visp.html for more information.
 *
 * This software was developed at:
 * INRIA Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 * http://www.irisa.fr/lagadic
 *
 * 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:
 * Alpha moment descriptor for in-plane orientation.
 *
 * Authors:
 * Filip Novotny
 *
 *****************************************************************************/

#include <visp/vpMomentAlpha.h>
#include <visp/vpMomentGravityCenter.h>
#include <visp/vpMomentCentered.h>  
#include <cmath>

vpMomentAlpha::vpMomentAlpha() : vpMoment(),isRef(true), symmetric(false){
    values.resize(1);
}

vpMomentAlpha::vpMomentAlpha(std::vector<double>& ref,double alphaRef) : vpMoment(),isRef(false),symmetric(false),ref(ref),alphaRef(alphaRef){
    for (std::vector<double>::iterator it = ref.begin(); it!=ref.end(); it++)
        if (*it<=1e-4)
            symmetric = true;

    values.resize(1);
}

void vpMomentAlpha::compute(){
    //symmetric = symmetric | this->getObject().isSymmetric();
  bool found_moment_centered;

  vpMomentCentered& momentCentered = (static_cast<vpMomentCentered&> (getMoments().get("vpMomentCentered",
                                                                                       found_moment_centered)));

  if (!found_moment_centered)
    throw vpException(vpException::notInitialized, "vpMomentCentered not found");

  double alpha = 0.5 * atan2(2.0 * momentCentered.get(1, 1), (momentCentered.get(2, 0) - momentCentered.get(0, 2)));

  unsigned int order = 4;
  std::vector<double> rotMu(4);
  std::vector<double> realMu(4);

  if (isRef)
  {
    alphaRef = alpha;
  }
  else
  {
    if (!symmetric)
    {
      double r11 = cos(alpha - alphaRef);
      double r12 = sin(alpha - alphaRef);
      double r21 = -sin(alpha - alphaRef);
      double r22 = cos(alpha - alphaRef);
      unsigned int idx = 0;
      for (register unsigned int c = 0; c < (order) * (order); c++)
      {
        unsigned int i = c % order;
        unsigned int j = c / order;

        if (i + j == 3)
        {
          double r11_k = 1.;
          for (register unsigned int k = 0; k <= i; k++)
          {
            double r12_i_k = pow(r12, (int)(i - k));
            double comb_i_k = static_cast<double> (vpMath::comb(i, k));
            for (register unsigned int l = 0; l <= j; l++)
            {
              rotMu[idx] += static_cast<double> (comb_i_k * vpMath::comb(j, l) * r11_k * pow(r21, (int)l) * r12_i_k
                  * pow(r22, (int)(j - l)) * momentCentered.get(k + l, (unsigned int)(int)(i + j - k - l)));
            }
            r11_k *= r11;
          }
          realMu[idx] = momentCentered.get(i, j);
          idx++;
        }
      }

      double sum = 0.;
      bool signChange = true;
      for (register unsigned int i = 0; i < 4; i++)
      {
        if (std::abs(rotMu[i]) > 1e10 * std::numeric_limits<double>::epsilon() && std::abs(ref[i]) > 1e10
            * std::numeric_limits<double>::epsilon() && rotMu[i] * ref[i] > 0)
          signChange = false;
        sum += std::abs(rotMu[i] * ref[i]);
      }

      if (sum < 1e4 * std::numeric_limits<double>::epsilon())
        signChange = false;
      if (signChange)
        alpha = alpha + M_PI;
    }
  }
  values[0] = alpha; 
}

std::ostream & operator<<(std::ostream & os, const vpMomentAlpha& c){
    os << c.values[0] ;
    return os;    
}