83 lines
2.6 KiB
C++
83 lines
2.6 KiB
C++
// Copyright (c) 2014 INRIA Sophia-Antipolis (France).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org).
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/Point_set_processing_3/include/CGAL/vcm_estimate_edges.h $
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// $Id: vcm_estimate_edges.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
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// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
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//
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// Author(s) : Jocelyn Meyron and Quentin Mérigot
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//
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#ifndef CGAL_VCM_ESTIMATE_EDGES_H
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#define CGAL_VCM_ESTIMATE_EDGES_H
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#include <CGAL/license/Point_set_processing_3.h>
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#include <CGAL/disable_warnings.h>
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#include <CGAL/vcm_estimate_normals.h>
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namespace CGAL {
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/// \ingroup PkgPointSetProcessing3Algorithms
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/// determines if a point is on a sharp feature edge from a point set
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/// for which the Voronoi covariance Measures have been computed.
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///
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/// The sharpness of the edge, specified by parameter `threshold`,
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/// is used to filtered points according to the external angle around a sharp feature.
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///
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/// A point is considered to be on a sharp feature if the external angle `alpha` at the edge is such that
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/// `alpha >= 2 / sqrt(3) * sqrt(threshold)`.
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/// In particular this means that if the input contains sharp features
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/// with different external angles, the one with the smallest external angle should be considered,
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/// which however would result in selecting more points on sharper regions.
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/// More details are provided in \cgalCite{cgal:mog-vbcfe-11}.
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///
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/// \tparam VCMTraits is a model of `DiagonalizeTraits`. It can be
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/// omitted: if Eigen 3 (or greater) is available and
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/// `CGAL_EIGEN3_ENABLED` is defined then an overload using
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/// `Eigen_diagonalize_traits` is provided. Otherwise, the internal
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/// implementation `Diagonalize_traits` is used.
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/// \sa CGAL::compute_vcm()`
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///
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template <class FT, class VCMTraits>
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bool
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vcm_is_on_feature_edge (std::array<FT,6> &cov,
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double threshold,
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VCMTraits)
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{
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std::array<double,3> eigenvalues;
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if (!VCMTraits::
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diagonalize_selfadjoint_covariance_matrix(cov, eigenvalues) )
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{
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return false;
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}
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// Compute the ratio
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double r = eigenvalues[1] / (eigenvalues[0] + eigenvalues[1] + eigenvalues[2]);
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if (r >= threshold)
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return true;
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return false;
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}
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template <class FT>
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bool
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vcm_is_on_feature_edge (std::array<FT,6> &cov,
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double threshold)
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{
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return vcm_is_on_feature_edge(cov, threshold,
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CGAL::Default_diagonalize_traits<double, 3>());
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}
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} // namespace CGAL
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#include <CGAL/enable_warnings.h>
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#endif // CGAL_VCM_ESTIMATE_EDGES_H
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