TMatchingPair.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#include "base-precomp.h"  // Precompiled headers

#include <mrpt/utils/TMatchingPair.h>
#include <mrpt/utils/CFileOutputStream.h>
#include <mrpt/utils/utils_defs.h>
#include <mrpt/poses/CPose2D.h>
#include <mrpt/system/os.h>
#include <mrpt/math/ops_containers.h>

using namespace mrpt;
using namespace mrpt::utils;
using namespace mrpt::math;
using namespace mrpt::poses;
using namespace mrpt::system;
using namespace std;

/*---------------------------------------------------------------
                                                dumpToFile
  ---------------------------------------------------------------*/
void TMatchingPairList::dumpToFile(const std::string& fileName) const
{
        CFileOutputStream f(fileName);
        ASSERT_(f.fileOpenCorrectly())

        for (const_iterator it = begin(); it != end(); ++it)
        {
                f.printf(
                        "%u %u %f %f %f %f %f %f %f\n", it->this_idx, it->other_idx,
                        it->this_x, it->this_y, it->this_z, it->other_x, it->other_y,
                        it->other_z, it->errorSquareAfterTransformation);
        }
}

/*---------------------------------------------------------------
                                                saveAsMATLABScript
  ---------------------------------------------------------------*/
void TMatchingPairList::saveAsMATLABScript(const std::string& filName) const
{
        FILE* f = os::fopen(filName.c_str(), "wt");

        fprintf(f, "%% ----------------------------------------------------\n");
        fprintf(f, "%%  File generated automatically by the MRPT method:\n");
        fprintf(f, "%%   saveAsMATLABScript  \n");
        fprintf(
                f, "%%  Before calling this script, define the color of lines, eg:\n");
        fprintf(f, "%%     colorLines=[1 1 1]");
        fprintf(f, "%%               J.L. Blanco (C) 2005-2012 \n");
        fprintf(f, "%% ----------------------------------------------------\n\n");

        fprintf(f, "axis equal; hold on;\n");
        for (const_iterator it = begin(); it != end(); ++it)
        {
                fprintf(
                        f, "line([%f %f],[%f %f],'Color',colorLines);\n", it->this_x,
                        it->other_x, it->this_y, it->other_y);
                fprintf(
                        f,
                        "set(plot([%f %f],[%f "
                        "%f],'.'),'Color',colorLines,'MarkerSize',15);\n",
                        it->this_x, it->other_x, it->this_y, it->other_y);
        }
        os::fclose(f);
}

/*---------------------------------------------------------------
                                                indexOtherMapHasCorrespondence
  ---------------------------------------------------------------*/
bool TMatchingPairList::indexOtherMapHasCorrespondence(size_t idx) const
{
        for (const_iterator it = begin(); it != end(); ++it)
        {
                if (it->other_idx == idx) return true;
        }
        return false;
}

bool mrpt::utils::operator<(const TMatchingPair& a, const TMatchingPair& b)
{
        if (a.this_idx == b.this_idx)
                return (a.this_idx < b.this_idx);
        else
                return (a.other_idx < b.other_idx);
}

bool mrpt::utils::operator==(const TMatchingPair& a, const TMatchingPair& b)
{
        return (a.this_idx == b.this_idx) && (a.other_idx == b.other_idx);
}

bool mrpt::utils::operator==(
        const TMatchingPairList& a, const TMatchingPairList& b)
{
        if (a.size() != b.size()) return false;
        for (TMatchingPairList::const_iterator it1 = a.begin(), it2 = b.begin();
                 it1 != a.end(); ++it1, ++it2)
                if (!((*it1) == (*it2))) return false;
        return true;
}

/*---------------------------------------------------------------
                                                overallSquareError
  ---------------------------------------------------------------*/
float TMatchingPairList::overallSquareError(const CPose2D& q) const
{
        vector<float> errs(size());
        squareErrorVector(q, errs);
        return math::sum(errs);
}

/*---------------------------------------------------------------
                                                overallSquareErrorAndPoints
  ---------------------------------------------------------------*/
float TMatchingPairList::overallSquareErrorAndPoints(
        const CPose2D& q, vector<float>& xs, vector<float>& ys) const
{
        vector<float> errs(size());
        squareErrorVector(q, errs, xs, ys);
        return math::sum(errs);
}

/*---------------------------------------------------------------
                                        TMatchingPairList::contains
  ---------------------------------------------------------------*/
bool TMatchingPairList::contains(const TMatchingPair& p) const
{
        for (const_iterator corresp = begin(); corresp != end(); ++corresp)
                if (*corresp == p) return true;
        return false;
}

/*---------------------------------------------------------------
                                                squareErrorVector
  ---------------------------------------------------------------*/
void TMatchingPairList::squareErrorVector(
        const CPose2D& q, vector<float>& out_sqErrs) const
{
        out_sqErrs.resize(size());
        // *    \f[ e_i = | x_{this} -  q \oplus x_{other}  |^2 \f]

        const float ccos = cos(q.phi());
        const float csin = sin(q.phi());
        const float qx = q.x();
        const float qy = q.y();

        const_iterator corresp;
        vector<float>::iterator e_i;
        for (corresp = begin(), e_i = out_sqErrs.begin(); corresp != end();
                 ++corresp, ++e_i)
        {
                float xx = qx + ccos * corresp->other_x - csin * corresp->other_y;
                float yy = qy + csin * corresp->other_x + ccos * corresp->other_y;
                *e_i = square(corresp->this_x - xx) + square(corresp->this_y - yy);
        }
}

/*---------------------------------------------------------------
                                                squareErrorVector
  ---------------------------------------------------------------*/
void TMatchingPairList::squareErrorVector(
        const CPose2D& q, vector<float>& out_sqErrs, vector<float>& xs,
        vector<float>& ys) const
{
        out_sqErrs.resize(size());
        xs.resize(size());
        ys.resize(size());

        // *    \f[ e_i = | x_{this} -  q \oplus x_{other}  |^2 \f]

        const float ccos = cos(q.phi());
        const float csin = sin(q.phi());
        const float qx = q.x();
        const float qy = q.y();

        const_iterator corresp;
        vector<float>::iterator e_i, xx, yy;
        for (corresp = begin(), e_i = out_sqErrs.begin(), xx = xs.begin(),
                yy = ys.begin();
                 corresp != end(); ++corresp, ++e_i, ++xx, ++yy)
        {
                *xx = qx + ccos * corresp->other_x - csin * corresp->other_y;
                *yy = qy + csin * corresp->other_x + ccos * corresp->other_y;
                *e_i = square(corresp->this_x - *xx) + square(corresp->this_y - *yy);
        }
}

void TMatchingPairList::filterUniqueRobustPairs(
        const size_t num_elements_this_map,
        TMatchingPairList& out_filtered_list) const
{
        std::vector<TMatchingPairConstPtr> bestMatchForThisMap(
                num_elements_this_map, TMatchingPairConstPtr(nullptr));
        out_filtered_list.clear();

        // 1) Go through all the correspondences and keep the best corresp.
        //    for each "global map" (this) point.
        for (auto& c : *this)
        {
                if (bestMatchForThisMap[c.this_idx] == nullptr ||  // first one
                        c.errorSquareAfterTransformation <
                                bestMatchForThisMap[c.this_idx]
                                        ->errorSquareAfterTransformation  // or better
                        )
                {
                        bestMatchForThisMap[c.this_idx] = &c;
                }
        }

        //   2) Go again through the list of correspondences and remove those
        //       who are not the best one for their corresponding global map.
        for (auto& c : *this)
        {
                if (bestMatchForThisMap[c.this_idx] == &c)
                        out_filtered_list.push_back(c);  // Add to the output
        }
}