ransac_applications.cpp

Go to the documentation of this file.

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2019, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

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

//#include <mrpt/math/eigen_extensions.h>
#include <mrpt/math/ransac_applications.h>

using namespace mrpt;
using namespace mrpt::math;
using namespace std;

/*---------------------------------------------------------------
        Aux. functions needed by ransac_detect_3D_planes
 ---------------------------------------------------------------*/
namespace mrpt
{
namespace math
{
template <typename T>
void ransac3Dplane_fit(
    const CMatrixDynamic<T>& allData, const std::vector<size_t>& useIndices,
    vector<CMatrixDynamic<T>>& fitModels)
{
    ASSERT_(useIndices.size() == 3);

    TPoint3D p1(
        allData(0, useIndices[0]), allData(1, useIndices[0]),
        allData(2, useIndices[0]));
    TPoint3D p2(
        allData(0, useIndices[1]), allData(1, useIndices[1]),
        allData(2, useIndices[1]));
    TPoint3D p3(
        allData(0, useIndices[2]), allData(1, useIndices[2]),
        allData(2, useIndices[2]));

    try
    {
        TPlane plane(p1, p2, p3);
        fitModels.resize(1);
        CMatrixDynamic<T>& M = fitModels[0];

        M.setSize(1, 4);
        for (size_t i = 0; i < 4; i++) M(0, i) = T(plane.coefs[i]);
    }
    catch (exception&)
    {
        fitModels.clear();
        return;
    }
}

template <typename T>
void ransac3Dplane_distance(
    const CMatrixDynamic<T>& allData,
    const vector<CMatrixDynamic<T>>& testModels, const T distanceThreshold,
    unsigned int& out_bestModelIndex, std::vector<size_t>& out_inlierIndices)
{
    ASSERT_(testModels.size() == 1);
    out_bestModelIndex = 0;
    const CMatrixDynamic<T>& M = testModels[0];

    ASSERT_(M.rows() == 1 && M.cols() == 4);

    TPlane plane;
    plane.coefs[0] = M(0, 0);
    plane.coefs[1] = M(0, 1);
    plane.coefs[2] = M(0, 2);
    plane.coefs[3] = M(0, 3);

    const size_t N = allData.cols();
    out_inlierIndices.clear();
    out_inlierIndices.reserve(100);
    for (size_t i = 0; i < N; i++)
    {
        const double d = plane.distance(
            TPoint3D(allData(0, i), allData(1, i), allData(2, i)));
        if (d < distanceThreshold) out_inlierIndices.push_back(i);
    }
}

/** Return "true" if the selected points are a degenerate (invalid) case.
 */
template <typename T>
bool ransac3Dplane_degenerate(
    const CMatrixDynamic<T>& allData, const std::vector<size_t>& useIndices)
{
    MRPT_UNUSED_PARAM(allData);
    MRPT_UNUSED_PARAM(useIndices);
    return false;
}
}  // namespace math
}  // namespace mrpt

/*---------------------------------------------------------------
                ransac_detect_3D_planes
 ---------------------------------------------------------------*/
template <typename NUMTYPE>
void mrpt::math::ransac_detect_3D_planes(
    const CVectorDynamic<NUMTYPE>& x, const CVectorDynamic<NUMTYPE>& y,
    const CVectorDynamic<NUMTYPE>& z,
    vector<pair<size_t, TPlane>>& out_detected_planes, const double threshold,
    const size_t min_inliers_for_valid_plane)
{
    MRPT_START

    ASSERT_(x.size() == y.size() && x.size() == z.size());

    out_detected_planes.clear();

    if (x.empty()) return;

    // The running lists of remaining points after each plane, as a matrix:
    CMatrixDynamic<NUMTYPE> remainingPoints(3, x.size());
    remainingPoints.setRow(0, x);
    remainingPoints.setRow(1, y);
    remainingPoints.setRow(2, z);

    // ---------------------------------------------
    // For each plane:
    // ---------------------------------------------
    for (;;)
    {
        std::vector<size_t> this_best_inliers;
        CMatrixDynamic<NUMTYPE> this_best_model;

        math::RANSAC_Template<NUMTYPE> ransac;
        ransac.setVerbosityLevel(mrpt::system::LVL_INFO);
        ransac.execute(
            remainingPoints, mrpt::math::ransac3Dplane_fit<NUMTYPE>,
            mrpt::math::ransac3Dplane_distance<NUMTYPE>,
            mrpt::math::ransac3Dplane_degenerate<NUMTYPE>, threshold,
            3,  // Minimum set of points
            this_best_inliers, this_best_model,
            0.999  // Prob. of good result
        );

        // Is this plane good enough?
        if (this_best_inliers.size() >= min_inliers_for_valid_plane)
        {
            // Add this plane to the output list:
            out_detected_planes.emplace_back(
                this_best_inliers.size(), TPlane(
                                              double(this_best_model(0, 0)),
                                              double(this_best_model(0, 1)),
                                              double(this_best_model(0, 2)),
                                              double(this_best_model(0, 3))));

            out_detected_planes.rbegin()->second.unitarize();

            // Discard the selected points so they are not used again for
            // finding subsequent planes:
            remainingPoints.removeColumns(this_best_inliers);
        }
        else
        {
            break;  // Do not search for more planes.
        }
    }

    MRPT_END
}

// Template explicit instantiations:
#define EXPLICIT_INST_ransac_detect_3D_planes(_TYPE_)                     \
    template void mrpt::math::ransac_detect_3D_planes<_TYPE_>(            \
        const CVectorDynamic<_TYPE_>& x, const CVectorDynamic<_TYPE_>& y, \
        const CVectorDynamic<_TYPE_>& z,                                  \
        vector<pair<size_t, TPlane>>& out_detected_planes,                \
        const double threshold, const size_t min_inliers_for_valid_plane)

EXPLICIT_INST_ransac_detect_3D_planes(float);
EXPLICIT_INST_ransac_detect_3D_planes(double);

/*---------------------------------------------------------------
        Aux. functions needed by ransac_detect_2D_lines
 ---------------------------------------------------------------*/
namespace mrpt
{
namespace math
{
template <typename T>
void ransac2Dline_fit(
    const CMatrixDynamic<T>& allData, const std::vector<size_t>& useIndices,
    vector<CMatrixDynamic<T>>& fitModels)
{
    ASSERT_(useIndices.size() == 2);

    TPoint2D p1(allData(0, useIndices[0]), allData(1, useIndices[0]));
    TPoint2D p2(allData(0, useIndices[1]), allData(1, useIndices[1]));

    try
    {
        TLine2D line(p1, p2);
        fitModels.resize(1);
        CMatrixDynamic<T>& M = fitModels[0];

        M.setSize(1, 3);
        for (size_t i = 0; i < 3; i++) M(0, i) = line.coefs[i];
    }
    catch (exception&)
    {
        fitModels.clear();
        return;
    }
}

template <typename T>
void ransac2Dline_distance(
    const CMatrixDynamic<T>& allData,
    const vector<CMatrixDynamic<T>>& testModels, const T distanceThreshold,
    unsigned int& out_bestModelIndex, std::vector<size_t>& out_inlierIndices)
{
    out_inlierIndices.clear();
    out_bestModelIndex = 0;

    if (testModels.empty()) return;  // No model, no inliers.

    ASSERTMSG_(
        testModels.size() == 1,
        format(
            "Expected testModels.size()=1, but it's = %u",
            static_cast<unsigned int>(testModels.size())));
    const CMatrixDynamic<T>& M = testModels[0];

    ASSERT_(M.rows() == 1 && M.cols() == 3);

    TLine2D line;
    line.coefs[0] = M(0, 0);
    line.coefs[1] = M(0, 1);
    line.coefs[2] = M(0, 2);

    const size_t N = allData.cols();
    out_inlierIndices.reserve(100);
    for (size_t i = 0; i < N; i++)
    {
        const double d = line.distance(TPoint2D(allData(0, i), allData(1, i)));
        if (d < distanceThreshold) out_inlierIndices.push_back(i);
    }
}

/** Return "true" if the selected points are a degenerate (invalid) case.
 */
template <typename T>
bool ransac2Dline_degenerate(
    const CMatrixDynamic<T>& allData, const std::vector<size_t>& useIndices)
{
    MRPT_UNUSED_PARAM(allData);
    MRPT_UNUSED_PARAM(useIndices);
    return false;
}
}  // namespace math
}  // namespace mrpt

/*---------------------------------------------------------------
                ransac_detect_2D_lines
 ---------------------------------------------------------------*/
template <typename NUMTYPE>
void mrpt::math::ransac_detect_2D_lines(
    const CVectorDynamic<NUMTYPE>& x, const CVectorDynamic<NUMTYPE>& y,
    std::vector<std::pair<size_t, TLine2D>>& out_detected_lines,
    const double threshold, const size_t min_inliers_for_valid_line)
{
    MRPT_START
    ASSERT_(x.size() == y.size());
    out_detected_lines.clear();

    if (x.empty()) return;

    // The running lists of remaining points after each plane, as a matrix:
    CMatrixDynamic<NUMTYPE> remainingPoints(2, x.size());
    remainingPoints.setRow(0, x);
    remainingPoints.setRow(1, y);

    // ---------------------------------------------
    // For each line:
    // ---------------------------------------------
    while (remainingPoints.cols() >= 2)
    {
        std::vector<size_t> this_best_inliers;
        CMatrixDynamic<NUMTYPE> this_best_model;

        math::RANSAC_Template<NUMTYPE> ransac;
        ransac.setVerbosityLevel(mrpt::system::LVL_INFO);
        ransac.execute(
            remainingPoints, ransac2Dline_fit<NUMTYPE>,
            ransac2Dline_distance<NUMTYPE>, ransac2Dline_degenerate<NUMTYPE>,
            threshold,
            2,  // Minimum set of points
            this_best_inliers, this_best_model,
            0.99999  // Prob. of good result
        );

        // Is this plane good enough?
        if (this_best_inliers.size() >= min_inliers_for_valid_line)
        {
            // Add this plane to the output list:
            out_detected_lines.emplace_back(
                this_best_inliers.size(), TLine2D(
                                              double(this_best_model(0, 0)),
                                              double(this_best_model(0, 1)),
                                              double(this_best_model(0, 2))));

            out_detected_lines.rbegin()->second.unitarize();

            // Discard the selected points so they are not used again for
            // finding subsequent planes:
            remainingPoints.removeColumns(this_best_inliers);
        }
        else
        {
            break;  // Do not search for more planes.
        }
    }

    MRPT_END
}

// Template explicit instantiations:
#define EXPLICIT_INSTANT_ransac_detect_2D_lines(_TYPE_)                   \
    template void mrpt::math::ransac_detect_2D_lines<_TYPE_>(             \
        const CVectorDynamic<_TYPE_>& x, const CVectorDynamic<_TYPE_>& y, \
        std::vector<std::pair<size_t, TLine2D>>& out_detected_lines,      \
        const double threshold, const size_t min_inliers_for_valid_line)

EXPLICIT_INSTANT_ransac_detect_2D_lines(float);
EXPLICIT_INSTANT_ransac_detect_2D_lines(double);