CGAL::Classification::Point_set_feature_generator< GeomTraits, PointRange, PointMap, ConcurrencyTag, DiagonalizeTraits > Class Template Reference

#include <CGAL/Classification/Point_set_feature_generator.h>

Definition

Generates a set of generic features for point set classification.

This class takes care of computing all necessary data structures and of generating a set of generic features at multiple scales to increase the reliability of the classification.

Template Parameters

GeomTraits	model of CGAL Kernel.
PointRange	model of ConstRange. Its iterator type is RandomAccessIterator and its value type is the key type of PointMap.
PointMap	model of ReadablePropertyMap whose key type is the value type of the iterator of PointRange and value type is GeomTraits::Point_3.
ConcurrencyTag	enables sequential versus parallel algorithm. Possible values are Parallel_tag (default value is CGAL is linked with TBB) or Sequential_tag (default value otherwise).
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.

Public Types
typedef GeomTraits::Iso_cuboid_3	Iso_cuboid_3
typedef Classification::Planimetric_grid< GeomTraits, PointRange, PointMap >	Planimetric_grid
typedef Classification::Point_set_neighborhood< GeomTraits, PointRange, PointMap >	Neighborhood
typedef Classification::Local_eigen_analysis	Local_eigen_analysis

Public Member Functions
template<typename VectorMap = Default, typename ColorMap = Default, typename EchoMap = Default>
	Point_set_feature_generator (Feature_set &features, const PointRange &input, PointMap point_map, std::size_t nb_scales, VectorMap normal_map=VectorMap(), ColorMap color_map=ColorMap(), EchoMap echo_map=EchoMap())
	Generates all possible features from an input range. More...
const Iso_cuboid_3 &	bbox () const
	Returns the bounding box of the input point set.
const Neighborhood &	neighborhood (std::size_t scale=0) const
	Returns the neighborhood structure at scale scale.
const Planimetric_grid &	grid (std::size_t scale=0) const
	Returns the planimetric grid structure at scale scale.
const Local_eigen_analysis &	eigen (std::size_t scale=0) const
	Returns the local eigen analysis structure at scale scale.
std::size_t	number_of_scales () const
	Returns the number of scales that were computed.
float	grid_resolution (std::size_t scale=0) const
	Returns the grid resolution at scale scale. More...
float	radius_neighbors (std::size_t scale=0) const
	Returns the radius used for neighborhood queries at scale scale. More...
float	radius_dtm (std::size_t scale=0) const
	Returns the radius used for digital terrain modeling at scale scale. More...

Constructor & Destructor Documentation

Point_set_feature_generator()

template<typename GeomTraits , typename PointRange , typename PointMap , typename ConcurrencyTag , typename DiagonalizeTraits >

template<typename VectorMap = Default, typename ColorMap = Default, typename EchoMap = Default>

CGAL::Classification::Point_set_feature_generator< GeomTraits, PointRange, PointMap, ConcurrencyTag, DiagonalizeTraits >::Point_set_feature_generator	(	Feature_set &	features,
		const PointRange &	input,
		PointMap	point_map,
		std::size_t	nb_scales,
		VectorMap	normal_map = VectorMap(),
		ColorMap	color_map = ColorMap(),
		EchoMap	echo_map = EchoMap()
	)

Generates all possible features from an input range.

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. At each scale, the following features are generated:

• CGAL::Classification::Feature::Anisotropy
• CGAL::Classification::Feature::Distance_to_plane
• CGAL::Classification::Feature::Eigentropy
• CGAL::Classification::Feature::Elevation
• CGAL::Classification::Feature::Linearity
• CGAL::Classification::Feature::Omnivariance
• CGAL::Classification::Feature::Planarity
• CGAL::Classification::Feature::Sphericity
• CGAL::Classification::Feature::Sum_eigenvalues
• CGAL::Classification::Feature::Surface_variation
• CGAL::Classification::Feature::Vertical_dispersion
• The version of CGAL::Classification::Feature::Verticality based on eigenvalues

If normal vectors are provided (if VectorMap is different from CGAL::Default), the following feature is generated at each scale:

• The version of CGAL::Classification::Feature::Verticality based on normal vectors

If colors are provided (if ColorMap is different from CGAL::Default), the following features are generated at each scale:

• 9 features CGAL::Classification::Feature::Hsv on channel 0 (hue) with mean ranging from 0° to 360° and standard deviation of 22.5.
• 5 features CGAL::Classification::Feature::Hsv on channel 1 (saturation) with mean ranging from 0 to 100 and standard deviation of 12.5.
• 5 features CGAL::Classification::Feature::Hsv on channel 2 (value) with mean ranging from 0 to 100 and standard deviation of 12.5.

If echo numbers are provided (if EchoMap is different from CGAL::Default), the following feature is computed at each scale:

• CGAL::Classification::Feature::Echo_scatter

Template Parameters

VectorMap	model of ReadablePropertyMap whose key type is the value type of the iterator of PointRange and value type is GeomTraits::Vector_3.
ColorMap	model of ReadablePropertyMap whose key type is the value type of the iterator of PointRange and value type is CGAL::Classification::RGB_Color.
EchoMap	model of ReadablePropertyMap whose key type is the value type of the iterator of PointRange and value type is std::size_t.

Parameters

features	the feature set where the features are instantiated.
input	point range.
point_map	property map to access the input points.
nb_scales	number of scales to compute.
normal_map	property map to access the normal vectors of the input points (if any).
color_map	property map to access the colors of the input points (if any).
echo_map	property map to access the echo values of the input points (if any).

Member Function Documentation

grid_resolution()

template<typename GeomTraits , typename PointRange , typename PointMap , typename ConcurrencyTag , typename DiagonalizeTraits >

float CGAL::Classification::Point_set_feature_generator< GeomTraits, PointRange, PointMap, ConcurrencyTag, DiagonalizeTraits >::grid_resolution

(

std::size_t

scale = 0

)

const

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.

radius_dtm()

template<typename GeomTraits , typename PointRange , typename PointMap , typename ConcurrencyTag , typename DiagonalizeTraits >

float CGAL::Classification::Point_set_feature_generator< GeomTraits, PointRange, PointMap, ConcurrencyTag, DiagonalizeTraits >::radius_dtm

(

std::size_t

scale = 0

)

const

Returns the radius used for digital terrain modeling at scale scale.

This radius represents the minimum size of a building at this scale.

radius_neighbors()

template<typename GeomTraits , typename PointRange , typename PointMap , typename ConcurrencyTag , typename DiagonalizeTraits >

float CGAL::Classification::Point_set_feature_generator< GeomTraits, PointRange, PointMap, ConcurrencyTag, DiagonalizeTraits >::radius_neighbors

(

std::size_t

scale = 0

)

const

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).