vpMomentAlpha.cpp

/****************************************************************************
 *
 * $Id: vpMomentAlpha.cpp 4649 2014-02-07 14:57:11Z fspindle $
 *
 * This file is part of the ViSP software.
 * Copyright (C) 2005 - 2014 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() : isRef(true), symmetric(false), ref(), alphaRef(0.) {
    values.resize(1);
}

vpMomentAlpha::vpMomentAlpha(std::vector<double>& ref_, double alpha_ref)
  : vpMoment(),isRef(false),symmetric(false),ref(ref_),alphaRef(alpha_ref)
{
  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;

    const vpMomentCentered& momentCentered = (static_cast<const 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;
}

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