CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, VertexToPointMap > Class Template Reference

#include <CGAL/Shape_detection/Region_growing/Polygon_mesh/Least_squares_plane_fit_region.h>

Definition

template<typename GeomTraits, typename PolygonMesh, typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::const_type>
class CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, VertexToPointMap >

Region type based on the quality of the least squares plane fit applied to faces of a polygon mesh.

This class fits a plane, using PCA, to chunks of faces in a polygon mesh and controls the quality of this fit. If all quality conditions are satisfied, the chunk is accepted as a valid region, otherwise rejected.

Template Parameters

GeomTraits	a model of Kernel
PolygonMesh	a model of FaceListGraph
VertexToPointMap	a model of ReadablePropertyMap whose key type is the vertex type of a polygon mesh (boost::graph_traits<PolygonMesh>::vertex_descriptor) and value type is GeomTraits::Point_3

Is model of

RegionType

Examples

Shape_detection/region_growing_planes_on_polygon_mesh.cpp.

Types
using	FT = typename GeomTraits::FT
	Number type.
using	Item = face_descriptor
	Item type.
using	Region = std::vector< Item >
using	Primitive = typename GeomTraits::Plane_3
	Primitive.
using	Region_index_map = typename boost::property_map< PolygonMesh, CGAL::dynamic_face_property_t< std::size_t > >::const_type
	Region map.

Initialization
template<typename NamedParameters = CGAL::parameters::Default_named_parameters>
	Least_squares_plane_fit_region (const PolygonMesh &pmesh, const NamedParameters &np=parameters::default_values())
	initializes all internal data structures.

Access
Region_index_map	region_index_map ()
	implements RegionType::region_index_map().
Primitive	primitive () const
	implements RegionType::primitive().
bool	is_part_of_region (const Item query, const Region &) const
	implements RegionType::is_part_of_region().
bool	is_valid_region (const Region &region) const
	implements RegionType::is_valid_region().
bool	update (const Region &region)
	implements RegionType::update().

Constructor & Destructor Documentation

Least_squares_plane_fit_region()

template<typename GeomTraits , typename PolygonMesh , typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::const_type>

template<typename NamedParameters = CGAL::parameters::Default_named_parameters>

CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, VertexToPointMap >::Least_squares_plane_fit_region	(	const PolygonMesh &	pmesh,
		const NamedParameters &	np = parameters::default_values()
	)

initializes all internal data structures.

Template Parameters

NamedParameters

a sequence of Named Parameters

Parameters

pmesh	an instance of PolygonMesh that represents a polygon mesh
np	a sequence of Named Parameters among the ones listed below

Optional Named Parameters

maximum_distance the maximum distance from a point to the plane of the primitive Type: GeomTraits::FT Default: 1
maximum_angle the maximum angle in degrees between the normal of a face and the normal of the plane of the primitive Type: GeomTraits::FT Default: 25 degrees
cosine_of_maximum_angle the cosine value cos(maximum_angle * PI / 180), to be used instead of the parameter maximum_angle() Type: GeomTraits::FT Default: cos(25 * PI / 180)
minimum_region_size the minimum number of faces a region must have Type: std::size_t Default: 1
vertex_point_map an instance of VertexToPointMap that maps a polygon mesh vertex (boost::graph_traits<PolygonMesh>::vertex_descriptor) to GeomTraits::Point_3 Default: boost::get(CGAL::vertex_point, pmesh)
face_normal_map a property map associating normal vectors to the faces of pmesh. Type: a class model of ReadablePropertyMap with boost::graph_traits<PolygonMesh>::face_descriptor as key type and GeomTraits::Vector_3 as value type. Default: If this parameter is omitted, face normals will be estimated using cross products of vectors created from consecutive vertices of the face.
geom_traits an instance of GeomTraits Default: GeomTraits()

Precondition

faces(pmesh).size() > 0

maximum_distance >= 0

maximum_angle >= 0 && maximum_angle <= 90

cosine_of_maximum_angle >= 0 && cosine_of_maximum_angle <= 1

minimum_region_size > 0

Member Function Documentation

is_part_of_region()

template<typename GeomTraits , typename PolygonMesh , typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::const_type>

bool CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, VertexToPointMap >::is_part_of_region	(	const Item	query,
		const Region &
	)		const

implements RegionType::is_part_of_region().

This function determines if the face query is within the maximum_distance from the corresponding plane and if the angle between its normal and the plane's normal is below the maximum_angle. If both conditions are satisfied, it returns true, otherwise false.

Parameters

query

item of the query face

Precondition

query is a valid face_descriptor (boost::graph_traits<PolygonMesh>::face_descriptor) of pmesh

is_valid_region()

template<typename GeomTraits , typename PolygonMesh , typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::const_type>

bool CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, VertexToPointMap >::is_valid_region

(

const Region &

region

)

const

implements RegionType::is_valid_region().

This function controls if the region contains at least minimum_region_size faces.

Parameters

region

Faces of the region represented as Items.

primitive()

template<typename GeomTraits , typename PolygonMesh , typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::const_type>

Primitive CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, VertexToPointMap >::primitive

(

)

const

implements RegionType::primitive().

This function provides the last primitive that has been fitted with the region.

Returns

Primitive parameters that fits the region.

Precondition

is_valid_region(region)

update(region)

region_index_map()

template<typename GeomTraits , typename PolygonMesh , typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::const_type>

Region_index_map CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, VertexToPointMap >::region_index_map

(

)

implements RegionType::region_index_map().

This function creates an empty property map that maps each face to a std::size_t.

update()

template<typename GeomTraits , typename PolygonMesh , typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::const_type>

bool CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, VertexToPointMap >::update

(

const Region &

region

)

implements RegionType::update().

This function fits the least squares plane to all vertices of the faces from the region.

Parameters

region

Faces of the region represented as Items.

Returns

Boolean true if the plane fitting succeeded and false otherwise

Precondition

region.size() > 0