Function computeHausdorffPair

pdal/PDALUtils.cpp:435–478

}

std::pair<double, double> computeHausdorffPair(PointViewPtr viewA,
                                               PointViewPtr viewB)
{
    // Computes both the max and mean of all nearest neighbor distances from
    // each point in the PointView to those in the KD3Index.
    auto compute = [](PointViewPtr view, KD3Index& index) {
        double max_distance = std::numeric_limits<double>::lowest();
        double M1(0.0);
        for (PointRef p : *view)
        {
            PointIdList indices(1);
            std::vector<double> sqr_dists(1);
            index.knnSearch(p, 1, &indices, &sqr_dists);

            if (sqr_dists[0] > max_distance)
                max_distance = sqr_dists[0];

            double delta = std::sqrt(sqr_dists[0]) - M1;
            double delta_n = delta / (p.pointId() + 1);
            M1 += delta_n;
        }
        max_distance = std::sqrt(max_distance);
        return std::pair<double, double>{max_distance, M1};
    };

    // First, test from view A to view B...
    KD3Index& indexB = viewB->build3dIndex();
    std::pair<double, double> a2b = compute(viewA, indexB);

    // then recompute from view B to view A.
    KD3Index& indexA = viewA->build3dIndex();
    std::pair<double, double> b2a = compute(viewB, indexA);

    // The original Hausdorff metric is the max of the max distances from A to B
    // and vice versa.
    double original = (std::max)(a2b.first, b2a.first);

    // The modified Hausdorff metric is the max of the mean distances from A to
    // B and vice versa.
    double modified = (std::max)(a2b.second, b2a.second);

    // Return both the original and modified metrics.
    return std::pair<double, double>{original, modified};
}

std::string dllDir()
{