cgal/Classification/include/CGAL/Classification/Mesh_feature_generator.h

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// Copyright (c) 2017 GeometryFactory Sarl (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL$
// $Id$
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s) : Simon Giraudot
#ifndef CGAL_CLASSIFICATION_MESH_FEATURE_GENERATOR_H
#define CGAL_CLASSIFICATION_MESH_FEATURE_GENERATOR_H
#include <CGAL/license/Classification.h>
#include <CGAL/property_map.h>
#include <CGAL/Classification/Mesh_neighborhood.h>
#include <CGAL/Classification/Planimetric_grid.h>
#include <CGAL/Classification/Local_eigen_analysis.h>
#include <CGAL/Classification/Feature_base.h>
#include <CGAL/Classification/Feature_set.h>
#include <CGAL/Classification/Feature/Distance_to_plane.h>
#include <CGAL/Classification/Feature/Echo_scatter.h>
#include <CGAL/Classification/Feature/Elevation.h>
#include <CGAL/Classification/Feature/Vertical_dispersion.h>
#include <CGAL/Classification/Feature/Verticality.h>
#include <CGAL/Classification/Feature/Eigenvalue.h>
#include <CGAL/Classification/Feature/Color_channel.h>
#include <CGAL/Classification/Feature/Height_below.h>
#include <CGAL/Classification/Feature/Height_above.h>
#include <CGAL/Classification/Feature/Vertical_range.h>
#include <CGAL/Classification/internal/verbosity.h>
#include <CGAL/bounding_box.h>
#include <CGAL/Real_timer.h>
namespace CGAL {
namespace Classification {
/*!
\ingroup PkgClassificationMesh
\brief generates a set of generic features for surface mesh
classification.
This class takes care of computing and storing all necessary data
structures and of generating a set of generic features at multiple
scales to increase the reliability of the classification.
A `PointMap` is required: this map should associate each face of the
mesh to a representative point (for example, the center of mass of
the face). It is used to generate point set features by considering
the mesh as a point set.
\warning The generated features use data structures that are stored
inside the generator. For this reason, the generator should be
instantiated _within the same scope_ as the feature set and should
not be deleted before the feature set.
\tparam GeomTraits model of \cgal Kernel.
\tparam FaceListGraph model of `FaceListGraph`.
\tparam PointMap model of `ReadablePropertyMap` whose key type is
`boost::graph_traits<FaceListGraph>::%face_descriptor` and value type
is `GeomTraits::Point_3`.
\tparam ConcurrencyTag enables sequential versus parallel
computation of `CGAL::Classification::Local_eigen_analysis`
objects. Possible values are `Parallel_tag` (default value if \cgal
is linked with TBB) or `Sequential_tag` (default value otherwise).
\tparam DiagonalizeTraits model of `DiagonalizeTraits` used for
matrix diagonalization. It can be omitted: if Eigen 3 (or greater)
is available and `CGAL_EIGEN3_ENABLED` is defined then an overload
using `Eigen_diagonalize_traits` is provided. Otherwise, the
internal implementation `Diagonalize_traits` is used.
*/
template <typename GeomTraits,
typename FaceListGraph,
typename PointMap,
#if defined(DOXYGEN_RUNNING)
typename ConcurrencyTag,
#else
typename ConcurrencyTag = CGAL::Parallel_if_available_tag,
#endif
typename DiagonalizeTraits = CGAL::Default_diagonalize_traits<float,3> >
class Mesh_feature_generator
{
public:
using Iso_cuboid_3 = typename GeomTraits::Iso_cuboid_3;
/// \cond SKIP_IN_MANUAL
using face_descriptor = typename boost::graph_traits<FaceListGraph>::face_descriptor;
using halfedge_descriptor = typename boost::graph_traits<FaceListGraph>::halfedge_descriptor;
using vertex_descriptor = typename boost::graph_traits<FaceListGraph>::vertex_descriptor;
using face_iterator = typename boost::graph_traits<FaceListGraph>::face_iterator;
using Face_range = typename CGAL::Iterator_range<face_iterator>;
using Point = typename PointMap::value_type;
using Face_map = CGAL::Identity_property_map<face_descriptor>;
/// \endcond
public:
using Planimetric_grid = Classification::Planimetric_grid<GeomTraits, Face_range, PointMap>;
using Neighborhood = Classification::Mesh_neighborhood<FaceListGraph>;
using Local_eigen_analysis = Classification::Local_eigen_analysis;
/// \cond SKIP_IN_MANUAL
using Feature_handle = Classification::Feature_handle;
using Distance_to_plane = Classification::Feature::Distance_to_plane<Face_range, PointMap>;
using Elevation = Classification::Feature::Elevation<GeomTraits, Face_range, PointMap>;
using Height_below = Classification::Feature::Height_below<GeomTraits, Face_range, PointMap>;
using Height_above = Classification::Feature::Height_above<GeomTraits, Face_range, PointMap>;
using Vertical_range = Classification::Feature::Vertical_range<GeomTraits, Face_range, PointMap>;
using Dispersion = Classification::Feature::Vertical_dispersion<GeomTraits, Face_range, PointMap>;
using Verticality = Classification::Feature::Verticality<GeomTraits>;
using Eigenvalue = Classification::Feature::Eigenvalue;
/// \endcond
private:
struct Scale
{
std::unique_ptr<Neighborhood> neighborhood;
std::unique_ptr<Planimetric_grid> grid;
std::unique_ptr<Local_eigen_analysis> eigen;
float voxel_size;
Scale (const FaceListGraph& input,
const Face_range& range,
PointMap point_map,
const Iso_cuboid_3& bbox, float voxel_size,
std::size_t nb_scale,
const std::unique_ptr<Planimetric_grid>& lower_grid
= std::unique_ptr<Planimetric_grid>())
: voxel_size (voxel_size)
{
CGAL::Real_timer t;
t.start();
neighborhood = std::make_unique<Neighborhood> (input);
t.stop();
CGAL_CLASSIFICATION_CERR << "Neighborhood computed in " << t.time() << " second(s)" << std::endl;
t.reset();
t.start();
eigen = std::make_unique<Local_eigen_analysis>
(Local_eigen_analysis::create_from_face_graph
(input, neighborhood->n_ring_neighbor_query(nb_scale + 1),
ConcurrencyTag(), DiagonalizeTraits()));
float mrange = eigen->mean_range();
if (this->voxel_size < 0)
this->voxel_size = mrange;
t.stop();
CGAL_CLASSIFICATION_CERR << "Eigen values computed in " << t.time() << " second(s)" << std::endl;
CGAL_CLASSIFICATION_CERR << "Range = " << mrange << std::endl;
t.reset();
t.start();
if (!lower_grid)
grid = std::make_unique<Planimetric_grid> (range, point_map, bbox, this->voxel_size);
else
grid = std::make_unique<Planimetric_grid>(lower_grid.get());
t.stop();
CGAL_CLASSIFICATION_CERR << "Planimetric grid computed in " << t.time() << " second(s)" << std::endl;
t.reset();
}
float grid_resolution() const { return voxel_size; }
float radius_neighbors() const { return voxel_size * 3; }
float radius_dtm() const { return voxel_size * 10; }
};
Iso_cuboid_3 m_bbox;
std::vector<std::unique_ptr<Scale> > m_scales;
const FaceListGraph& m_input;
Face_range m_range;
PointMap m_point_map;
public:
/// \name Constructor
/// @{
/*!
\brief initializes a feature generator from an input range.
If not provided by the user, The size of the smallest scale is
automatically estimated using a method equivalent to
`CGAL::compute_average_spacing()` using 6 neighbors. The data
structures needed (`Neighborhood`, `Planimetric_grid` and
`Local_eigen_analysis`) are computed at `nb_scales` recursively
larger scales.
\param input input mesh.
\param point_map property map to access a representative point of
each face.
\param nb_scales number of scales to compute.
\param voxel_size smallest scale used as a voxel size for the
planimetric grid (if the default value -1 is used, its value is
automatically estimated).
*/
Mesh_feature_generator(const FaceListGraph& input,
PointMap point_map,
std::size_t nb_scales,
float voxel_size = -1.f)
: m_input (input), m_range(faces(input)), m_point_map (point_map)
{
m_bbox = CGAL::bounding_box
(CGAL::make_transform_iterator_from_property_map (m_range.begin(), m_point_map),
CGAL::make_transform_iterator_from_property_map (m_range.end(), m_point_map));
CGAL::Real_timer t; t.start();
m_scales.reserve (nb_scales);
m_scales.emplace_back (std::make_unique<Scale> (m_input, m_range, m_point_map, m_bbox, voxel_size, 0));
if (voxel_size == -1.f)
voxel_size = m_scales[0]->grid_resolution();
for (std::size_t i = 1; i < nb_scales; ++ i)
{
voxel_size *= 2;
m_scales.emplace_back (std::make_unique<Scale> (m_input, m_range, m_point_map, m_bbox, voxel_size, i, m_scales[i-1]->grid));
}
t.stop();
CGAL_CLASSIFICATION_CERR << "Scales computed in " << t.time() << " second(s)" << std::endl;
t.reset();
}
/// @}
/// \name Feature Generation
/// @{
/*!
\brief generates geometric features based on face information.
At each scale, the following features are generated:
- `CGAL::Classification::Feature::Eigenvalue` with indices 0, 1 and 2
- The version of `CGAL::Classification::Feature::Verticality` based on eigenvalues
\param features the feature set where the features are instantiated.
*/
void generate_face_based_features (Feature_set& features)
{
for (int j = 0; j < 3; ++ j)
for (std::size_t i = 0; i < m_scales.size(); ++ i)
features.add_with_scale_id<Eigenvalue> (i, m_range, eigen(i), (unsigned int)(j));
for (std::size_t i = 0; i < m_scales.size(); ++ i)
features.add_with_scale_id<Verticality> (i, m_range, eigen(i));
}
/*!
\brief generates geometric features based on point position information.
At each scale, the following features are generated by considering
the mesh as a point cloud through `PointMap`:
- `CGAL::Classification::Feature::Distance_to_plane`
- `CGAL::Classification::Feature::Elevation`
- `CGAL::Classification::Feature::Height_above`
- `CGAL::Classification::Feature::Height_below`
- `CGAL::Classification::Feature::Vertical_dispersion`
- `CGAL::Classification::Feature::Vertical_range`
\param features the feature set where the features are instantiated.
*/
void generate_point_based_features (Feature_set& features)
{
for (std::size_t i = 0; i < m_scales.size(); ++ i)
features.add_with_scale_id<Distance_to_plane> (i, m_range, m_point_map, eigen(i));
for (std::size_t i = 0; i < m_scales.size(); ++ i)
features.add_with_scale_id<Dispersion> (i, m_range, m_point_map, grid(i), radius_neighbors(i));
for (std::size_t i = 0; i < m_scales.size(); ++ i)
features.add_with_scale_id<Elevation> (i, m_range, m_point_map, grid(i), radius_dtm(i));
for (std::size_t i = 0; i < m_scales.size(); ++ i)
features.add_with_scale_id<Height_below> (i, m_range, m_point_map, grid(i));
for (std::size_t i = 0; i < m_scales.size(); ++ i)
features.add_with_scale_id<Height_above> (i, m_range, m_point_map, grid(i));
for (std::size_t i = 0; i < m_scales.size(); ++ i)
features.add_with_scale_id<Vertical_range> (i, m_range, m_point_map, grid(i));
}
/// @}
/// \name Data Structures Access
/// @{
/*!
\brief returns the bounding box of the input point set.
*/
const Iso_cuboid_3& bbox() const { return m_bbox; }
/*!
\brief returns the neighborhood structure at scale `scale`.
*/
const Neighborhood& neighborhood(std::size_t scale = 0) const { return (*m_scales[scale]->neighborhood); }
/*!
\brief returns the planimetric grid structure at scale `scale`.
*/
const Planimetric_grid& grid(std::size_t scale = 0) const { return *(m_scales[scale]->grid); }
/*!
\brief returns the local eigen analysis structure at scale `scale`.
*/
const Local_eigen_analysis& eigen(std::size_t scale = 0) const { return *(m_scales[scale]->eigen); }
/// @}
/// \name Parameters
/// @{
/*!
\brief returns the number of scales that were computed.
*/
std::size_t number_of_scales() const { return m_scales.size(); }
/*!
\brief returns the grid resolution at scale `scale`. This
resolution is the length and width of a cell of the
`Planimetric_grid` defined at this scale.
*/
float grid_resolution(std::size_t scale = 0) const { return m_scales[scale]->grid_resolution(); }
/*!
\brief returns the radius used for neighborhood queries at scale
`scale`. This radius is the smallest radius that is relevant from
a geometric point of view at this scale (that is to say that
encloses a few cells of `Planimetric_grid`).
*/
float radius_neighbors(std::size_t scale = 0) const { return m_scales[scale]->radius_neighbors(); }
/*!
\brief returns the radius used for digital terrain modeling at
scale `scale`. This radius represents the minimum size of a
building at this scale.
*/
float radius_dtm(std::size_t scale = 0) const { return m_scales[scale]->radius_dtm(); }
/// @}
};
} // namespace Classification
} // namespace CGAL
#endif // CGAL_CLASSIFICATION_MESH_FEATURE_GENERATOR_H