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

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

Definition

template<typename GeomTraits, typename PolygonMesh, typename FaceRange = typename PolygonMesh::Face_range, typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::type>
class CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, FaceRange, 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	must be a model of Kernel.
PolygonMesh	must be a model of FaceListGraph.
FaceRange	must be a model of ConstRange whose iterator type is RandomAccessIterator and value type is the face type of a polygon mesh.
VertexToPointMap	must be an LvaluePropertyMap whose key type is the vertex type of a polygon mesh and value type is Kernel::Point_3.

Is Model Of:

RegionType

Examples:

Shape_detection/region_growing_on_polygon_mesh.cpp.

Types
typedef GeomTraits::FT	FT
	Number type.

Initialization
	Least_squares_plane_fit_region (const PolygonMesh &pmesh, const FT distance_threshold=FT(1), const FT angle_threshold=FT(25), const std::size_t min_region_size=1, const VertexToPointMap vertex_to_point_map=VertexToPointMap(), const GeomTraits traits=GeomTraits())
	initializes all internal data structures. More...

Access
bool	is_part_of_region (const std::size_t, const std::size_t query_index, const std::vector< std::size_t > &) const
	implements RegionType::is_part_of_region(). More...
bool	is_valid_region (const std::vector< std::size_t > &region) const
	implements RegionType::is_valid_region(). More...
void	update (const std::vector< std::size_t > &region)
	implements RegionType::update(). More...

Constructor & Destructor Documentation

Least_squares_plane_fit_region()

template<typename GeomTraits , typename PolygonMesh , typename FaceRange = typename PolygonMesh::Face_range, typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::type>

CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, FaceRange, VertexToPointMap >::Least_squares_plane_fit_region	(	const PolygonMesh &	pmesh,
		const FT	distance_threshold = FT(1),
		const FT	angle_threshold = FT(25),
		const std::size_t	min_region_size = 1,
		const VertexToPointMap	vertex_to_point_map = VertexToPointMap(),
		const GeomTraits	traits = GeomTraits()
	)

initializes all internal data structures.

Parameters

pmesh	an instance of PolygonMesh that represents a polygon mesh
distance_threshold	the maximum distance from the furthest vertex of a face to a plane. Default is 1.
angle_threshold	the maximum accepted angle in degrees between the normal of a face and the normal of a plane. Default is 25 degrees.
min_region_size	the minimum number of faces a region must have. Default is 1.
vertex_to_point_map	an instance of VertexToPointMap that maps a polygon mesh vertex to Kernel::Point_3
traits	an instance of GeomTraits

Precondition

faces(pmesh).size() > 0

distance_threshold >= 0

angle_threshold >= 0 && angle_threshold <= 90

min_region_size > 0

Member Function Documentation

is_part_of_region()

template<typename GeomTraits , typename PolygonMesh , typename FaceRange = typename PolygonMesh::Face_range, typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::type>

bool CGAL::Shape_detection::Polygon_mesh::Least_squares_plane_fit_region< GeomTraits, PolygonMesh, FaceRange, VertexToPointMap >::is_part_of_region	(	const std::size_t	,
		const std::size_t	query_index,
		const std::vector< std::size_t > &
	)		const

implements RegionType::is_part_of_region().

This function controls if a face with the index query_index is within the distance_threshold from the corresponding plane and if the angle between its normal and the plane's normal is within the angle_threshold. If both conditions are satisfied, it returns true, otherwise false.

Parameters

query_index

index of the query face

The first and third parameters are not used in this implementation.

Returns

Boolean true or false

Precondition

query_index >= 0 && query_index < faces(pmesh).size()

is_valid_region()

template<typename GeomTraits , typename PolygonMesh , typename FaceRange = typename PolygonMesh::Face_range, typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::type>

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

(

const std::vector< std::size_t > &

region

)

const

implements RegionType::is_valid_region().

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

Parameters

region

indices of faces included in the region

Returns

Boolean true or false

update()

template<typename GeomTraits , typename PolygonMesh , typename FaceRange = typename PolygonMesh::Face_range, typename VertexToPointMap = typename boost::property_map<PolygonMesh, CGAL::vertex_point_t>::type>

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

(

const std::vector< std::size_t > &

region

)

implements RegionType::update().

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

Parameters

region

indices of faces included in the region

Precondition

region.size() > 0