Ejemplo n.º 1
0
double CovarianceModel::covMatrixDistance(const cv::Mat& a, const cv::Mat& b)
{
  // if the values are the same in each matrix, save the trouble of eigenvalues
  // the behaviour of the math is the same anyway
  if(cv::countNonZero(a == b) == a.cols*a.rows)
  {
    return 0.0;
  }
  else
  {
    double result = 0.0;
    // use the Eigen library to compute the generalized eigenvalues of two covariance matrices
    // Ax = \lambda Bx  where  x_k != 0
    Eigen::MatrixXd C_i, C_j;
    cv::cv2eigen(a, C_i);
    cv::cv2eigen(b, C_j);

    Eigen::GeneralizedSelfAdjointEigenSolver<Eigen::MatrixXd> es;
    es.compute(C_i, C_j, Eigen::ComputeEigenvectors|Eigen::Ax_lBx);

    cv::Mat eigenValues;
    cv::eigen2cv(Eigen::MatrixXd(es.eigenvalues().real()), eigenValues);

    for(int i=0; i<eigenValues.rows; ++i) // eigenValues.rows == 5
      result += pow(log(eigenValues.at<double>(i,0)), 2);  // ln^2 \lambda_k (C_i, C_j)
    //result = sqrt(result);

    // http://www.developerstation.org/2012/04/general-eigen-values-and-eigen-vectors.html
    // http://eigen.tuxfamily.org/dox/classEigen_1_1GeneralizedSelfAdjointEigenSolver.html#aaa204ef15aaefac270c0376269083ed6

    //    if(isnan(result))
    //    {
    //      /* Problem: the generalized eigenvalues of these matrices cannot be computed because
    //       * each column should be independent and zero vectors are clearly not like that.
    //       *Example:
    //        A:[0, 0, 0, 0, 0;
    //           0, 1482.289314516129, 0, 4.623991935483871, 0;
    //           0, 0, 0, 0, 0;
    //           0, 4.623991935483871, 0, 1138.168346774193, 0;
    //           0, 0, 0, 0, 0]
    //        B:[0, 0, 0, 0, 0;
    //           0, 21.51992753623188, 0, -1.005434782608696, 0;
    //           0, 0, 0, 0, 0;
    //           0, -1.005434782608696, 0, 11.07065217391304, 0;
    //           0, 0, 0, 0, 0]
    //      */
    //      std::cerr << "A:" << a << std::endl
    //                << "B:" << b << std::endl
    //                << "eigenvalues: " << eigenValues << std::endl
    //                << "distance: " << result << std::endl;
    //      throw std::runtime_error("distance is nan, possibly eigenvalues are also nan");
    //    }
    return result;
  }
}
Ejemplo n.º 2
0
float BodyRecognizer::calculateDistance(cv::Mat& d1, cv::Mat& d2)
{
  Eigen::GeneralizedSelfAdjointEigenSolver<Eigen::Matrix4f> ges;
  Eigen::Matrix4f d1Eigen;
  Eigen::Matrix4f d2Eigen;
  
  cv::cv2eigen(d1, d1Eigen); 
  cv::cv2eigen(d2, d2Eigen); 
  
  ges.compute(d1Eigen, d2Eigen);
  
  double sum;
  for(int i=0; i < ges.eigenvalues().size(); i++)
  {
    sum += pow(log(ges.eigenvalues()[i]), 2.0);
  }
  double d = sqrt(sum);
  //cout << "The generalzied eigenvalues are : " << ges.eigenvalues().transpose() << endl;
  std::cout << "distance is " << d << std::endl;
  return d;
}
Ejemplo n.º 3
0
void pclbo::LBOEstimation<PointT, NormalT>::compute() {

    typename pcl::KdTreeFLANN<PointT>::Ptr kdt(new pcl::KdTreeFLANN<PointT>());
    kdt->setInputCloud(_cloud);

    const double avg_dist = pclbo::avg_distance<PointT>(10, _cloud, kdt);
    const double h = 5 * avg_dist;

    std::cout << "Average distance between points: " << avg_dist << std::endl;

    int points_with_mass = 0;
    double avg_mass = 0.0;
    B.resize(_cloud->size());

    std::cout << "Computing the Mass matrix..." << std::flush;

    // Compute the mass matrix diagonal B
    for (int i = 0; i < _cloud->size(); i++) {
        const auto& point = _cloud->at(i);
        const auto& normal = _normals->at(i);

        const auto& normal_vector = normal.getNormalVector3fMap().template cast<double>();

        if (!pcl::isFinite(point)) continue;

        std::vector<int> indices;
        std::vector<float> distances;
        kdt->radiusSearch(point, h, indices, distances);

        if (indices.size() < 4) {
            B[i] = 0.0;
            continue;
        }

        // Project the neighbor points in the tangent plane at p_i with normal n_i
        std::vector<Eigen::Vector3d> projected_points;
        for (const auto& neighbor_index : indices) {
            if (neighbor_index != i) {
                const auto& neighbor_point = _cloud->at(neighbor_index);
                projected_points.push_back(project(point, normal, neighbor_point));
            }
        }

        assert(projected_points.size() >= 3);

        // Use the first vector to create a 2D basis
        Eigen::Vector3d u = projected_points[0];
        u.normalize();
        Eigen::Vector3d v = (u.cross(normal_vector));
        v.normalize();

        // Add the points to a 2D plane
        std::vector<Eigen::Vector2d> plane;

        // Add the point at the center
        plane.push_back(Eigen::Vector2d::Zero());

        // Add the rest of the points
        for (const auto& projected : projected_points) {

            double x = projected.dot(u);
            double y = projected.dot(v);

            // Add the 2D point to the vector
            plane.push_back(Eigen::Vector2d(x, y));
        }

        assert(plane.size() >= 4);

        // Compute the voronoi cell area of the point
        double area = VoronoiDiagram::area(plane);
        B[i] = area;
        avg_mass += area;
        points_with_mass++;
    }

    // Average mass
    if (points_with_mass > 0) {
        avg_mass /= static_cast<double>(points_with_mass);
    }

    // Set border points to have average mass
    for (auto& b : B) {
        if (b == 0.0) {
            b = avg_mass; 
        } 
    }

    std::cout << "done" << std::endl;
    std::cout << "Computing the stiffness matrix..." << std::flush;

    std::vector<double> diag(_cloud->size(), 0.0);

    // Compute the stiffness matrix Q
    for (int i = 0; i < _cloud->size(); i++) {
        const auto& point = _cloud->at(i);

        if (!pcl::isFinite(point)) continue;

        std::vector<int> indices;
        std::vector<float> distances;
        kdt->radiusSearch(point, h, indices, distances);

        for (const auto& j : indices) {
            if (j != i) {
                const auto& neighbor = _cloud->at(j);

                double d = (neighbor.getVector3fMap() - point.getVector3fMap()).norm();
                double w = B[i] * B[j] * (1.0 / (4.0 * M_PI * h * h)) * exp(-(d * d) / (4.0 * h));

                I.push_back(i);
                J.push_back(j);
                S.push_back(w);

                diag[i] += w;
            }
        }
    }

    // Fill the diagonal as the negative sum of the rows
    for (int i = 0; i < diag.size(); i++) {
        I.push_back(i);
        J.push_back(i);
        S.push_back(-diag[i]);
    }

    // Compute the B^{-1}Q matrix
    Eigen::MatrixXd Q = Eigen::MatrixXd::Zero(_cloud->size(), _cloud->size());
    for (int i = 0; i < I.size(); i++) {
        const int row = I[i];
        const int col = J[i];
        Q(row, col) = S[i];
    }

    std::cout << "done" << std::endl;
    std::cout << "Computing eigenvectors" << std::endl;

    Eigen::Map<Eigen::VectorXd> B_vec(B.data(), B.size());

    Eigen::GeneralizedSelfAdjointEigenSolver<Eigen::MatrixXd> ges;
    ges.compute(Q, B_vec.asDiagonal());

    eigenvalues = ges.eigenvalues();
    eigenfunctions = ges.eigenvectors();

    // Sort the eigenvalues by magnitude
    std::vector<std::pair<double, int> > map_vector(eigenvalues.size());

    for (auto i = 0; i < eigenvalues.size(); i++) {
        map_vector[i].first = std::abs(eigenvalues(i));
        map_vector[i].second = i;
    }

    std::sort(map_vector.begin(), map_vector.end());

    // truncate the first 100 eigenfunctions
    Eigen::MatrixXd eigenvectors(eigenfunctions.rows(), eigenfunctions.cols());
    Eigen::VectorXd eigenvals(eigenfunctions.cols());

    eigenvalues.resize(map_vector.size());
    for (auto i = 0; i < map_vector.size(); i++) {
        const auto& pair = map_vector[i];
        eigenvectors.col(i) = eigenfunctions.col(pair.second); 
        eigenvals(i) = pair.first;
    }

    eigenfunctions = eigenvectors;
    eigenvalues = eigenvals;
}