A specific point could structure to handle subsets of points, provided with several geometric processings. More...

#include <Neighbourhood.h>

Collaboration diagram for CCCoreLib::Neighbourhood:

[legend]

Public Types
enum	GeomElement { FLAG_DEPRECATED = 0 , FLAG_GRAVITY_CENTER = 1 , FLAG_LS_PLANE = 2 , FLAG_QUADRIC = 4 }
	Geometric properties/elements that can be computed from the set of points (see Neighbourhood::getGeometricalElement)

enum	CurvatureType { GAUSSIAN_CURV = 1 , MEAN_CURV , NORMAL_CHANGE_RATE }
	Curvature type.

enum	InputVectorsUsage { UseOXYasBase , UseYAsUpDir , None }
	Defines how input vectors of projectPointsOn2DPlane should be used.

enum	GeomFeature { EigenValuesSum = 1 , Omnivariance , EigenEntropy , Anisotropy , Planarity , Linearity , PCA1 , PCA2 , SurfaceVariation , Sphericity , Verticality , EigenValue1 , EigenValue2 , EigenValue3 }
	Geometric feature computed from eigen values/vectors. More...

Public Member Functions
	Neighbourhood (GenericIndexedCloudPersist *associatedCloud)
	Default constructor. More...

virtual	~Neighbourhood ()=default
	Default destructor.

virtual void	reset ()
	Resets structure (depreactes all associated geometrical fetaures)

GenericIndexedCloudPersist *	associatedCloud () const
	Returns associated cloud.

GenericIndexedMesh *	triangulateOnPlane (bool duplicateVertices, PointCoordinateType maxEdgeLength, std::string &outputErrorStr)
	Applies 2D Delaunay triangulation. More...

GenericIndexedMesh *	triangulateFromQuadric (unsigned stepsX, unsigned stepsY)
	Fit a quadric on point set (see getQuadric) then triangulates it inside bounding box.

template<class Vec2D >
bool	projectPointsOn2DPlane (std::vector< Vec2D > &points2D, const PointCoordinateType planeEquation=nullptr, CCVector3 O=nullptr, CCVector3 X=nullptr, CCVector3 Y=nullptr, InputVectorsUsage vectorsUsage=None)
	Projects points on the best fitting LS plane. More...

double	computeFeature (GeomFeature feature)
	Computes the given feature on a set of point. More...

ScalarType	computeMomentOrder1 (const CCVector3 &P)
	Computes the 1st order moment of a set of point (based on the eigenvalues) More...

ScalarType	computeRoughness (const CCVector3 &P, const CCVector3 *roughnessUpDir=nullptr)
	Computes the roughness of a point (by fitting a 2D plane on its neighbors) More...

ScalarType	computeCurvature (const CCVector3 &P, CurvatureType cType)
	Computes the curvature of a set of point (by fitting a 2.5D quadric) More...

const CCVector3 *	getGravityCenter ()
	Returns gravity center. More...

void	setGravityCenter (const CCVector3 &G)
	Sets gravity center. More...

const PointCoordinateType *	getLSPlane ()
	Returns best interpolating plane equation (Least-square) More...

void	setLSPlane (const PointCoordinateType eq[4], const CCVector3 &X, const CCVector3 &Y, const CCVector3 &N)
	Sets the best interpolating plane equation (Least-square) More...

const CCVector3 *	getLSPlaneX ()
	Returns best interpolating plane (Least-square) 'X' base vector. More...

const CCVector3 *	getLSPlaneY ()
	Returns best interpolating plane (Least-square) 'Y' base vector. More...

const CCVector3 *	getLSPlaneNormal ()
	Returns best interpolating plane (Least-square) normal vector. More...

const PointCoordinateType *	getQuadric (Tuple3ub *dims=nullptr)
	Returns the best interpolating 2.5D quadric. More...

bool	compute3DQuadric (double quadricEquation[10])
	Computes the best interpolating quadric (Least-square) More...

SquareMatrixd	computeCovarianceMatrix ()
	Computes the covariance matrix.

PointCoordinateType	computeLargestRadius ()
	Returns the set 'radius' (i.e. the distance between the gravity center and the its farthest point)

Static Public Attributes
static constexpr int	IGNORE_MAX_EDGE_LENGTH = 0

static constexpr bool	DUPLICATE_VERTICES = true

static constexpr bool	DO_NOT_DUPLICATE_VERTICES = false

Protected Member Functions
void	computeGravityCenter ()
	Computes the gravity center.

bool	computeLeastSquareBestFittingPlane ()
	Computes the least-square best fitting plane.

bool	computeQuadric ()
	Computes best fitting 2.5D quadric.

Protected Attributes
PointCoordinateType	m_quadricEquation [6]
	2.5D Quadric equation More...

Tuple3ub	m_quadricEquationDirections
	2.5D Quadric equation dimensions More...

PointCoordinateType	m_lsPlaneEquation [4]
	Least-square best fitting plane parameters. More...

CCVector3	m_lsPlaneVectors [3]
	Least-square best fitting plane base vectors. More...

CCVector3	m_gravityCenter
	Gravity center. More...

unsigned char	m_structuresValidity
	Geometrical elements validity (flags)

GenericIndexedCloudPersist *	m_associatedCloud
	Associated cloud.

Detailed Description

A specific point could structure to handle subsets of points, provided with several geometric processings.

Typically suited for "nearest neighbours". It implements the GenericIndexCloud interface by inheriting the ReferenceCloud class.

Member Enumeration Documentation

◆ GeomFeature

enum CCCoreLib::Neighbourhood::GeomFeature

Geometric feature computed from eigen values/vectors.

Most of them are defined in "Contour detection in unstructured 3D point clouds", Hackel et al, 2016 PCA1 and PCA2 are defined in "3D terrestrial lidar data classification of complex natural scenes using a multi-scale dimensionality criterion: Applications in geomorphology", Brodu and Lague, 2012

Constructor & Destructor Documentation

◆ Neighbourhood()

Neighbourhood::Neighbourhood ( GenericIndexedCloudPersist * associatedCloud )

explicit

Default constructor.

Parameters

associatedCloud reference cloud

Member Function Documentation

◆ compute3DQuadric()

bool Neighbourhood::compute3DQuadric ( double quadricEquation[10] )

Computes the best interpolating quadric (Least-square)

Parameters

[out] quadricEquation an array of 10 coefficients [a,b,c,d,e,f,g,l,m,n] such as a.x^2+b.y^2+c.z^2+2e.x.y+2f.y.z+2g.z.x+2l.x+2m.y+2n.z+d = 0

Returns: success

◆ computeCurvature()

ScalarType Neighbourhood::computeCurvature	(	const CCVector3 &	P,
		CurvatureType	cType
	)

Computes the curvature of a set of point (by fitting a 2.5D quadric)

Returns: curvature value at a given position P or CCCoreLib::NAN_VALUE if the computation failed

Warning: The curvature value is always unsigned

◆ computeFeature()

double Neighbourhood::computeFeature ( GeomFeature feature )

Computes the given feature on a set of point.

Returns: feature value

◆ computeMomentOrder1()

ScalarType Neighbourhood::computeMomentOrder1 ( const CCVector3 & P )

Computes the 1st order moment of a set of point (based on the eigenvalues)

Returns: 1st order moment at a given position P DGM: The article states that the result should be between 0 and 1, but this is actually wrong (as (a + b)^2 can be > a^2 + b^2)

◆ computeRoughness()

ScalarType Neighbourhood::computeRoughness	(	const CCVector3 &	P,
		const CCVector3 *	roughnessUpDir = `nullptr`
	)

Computes the roughness of a point (by fitting a 2D plane on its neighbors)

Parameters

P	point for which to compute the roughness value
roughnessUpDir	up direction to compute a signed roughness value (optional)

Returns: roughness value at a given position P

Warning: The point P shouldn't be in the set of points

◆ getGravityCenter()

const CCVector3 * Neighbourhood::getGravityCenter ( )

Returns gravity center.

Returns: 0 if computation failed

◆ getLSPlane()

const PointCoordinateType * Neighbourhood::getLSPlane ( )

Returns best interpolating plane equation (Least-square)

Returns an array of the form [a,b,c,d] such as: ax + by + cz = d

Returns: 0 if computation failed

◆ getLSPlaneNormal()

const CCVector3 * Neighbourhood::getLSPlaneNormal ( )

Returns best interpolating plane (Least-square) normal vector.

This corresponds to the smallest eigen value (i.e. the second largest cloud dimension)

Returns: 0 if computation failed

◆ getLSPlaneX()

const CCVector3 * Neighbourhood::getLSPlaneX ( )

Returns best interpolating plane (Least-square) 'X' base vector.

This corresponds to the largest eigen value (i.e. the largest cloud dimension)

Returns: 0 if computation failed

◆ getLSPlaneY()

const CCVector3 * Neighbourhood::getLSPlaneY ( )

Returns best interpolating plane (Least-square) 'Y' base vector.

This corresponds to the second largest eigen value (i.e. the second largest cloud dimension)

Returns: 0 if computation failed

◆ getQuadric()

const PointCoordinateType * Neighbourhood::getQuadric ( Tuple3ub * dims = nullptr )

Returns the best interpolating 2.5D quadric.

Returns an array of the form [a,b,c,d,e,f] such as: Z = a + b.X + c.Y + d.X^2 + e.X.Y + f.Y^2

Warning: : 'X','Y' and 'Z' are output in dims (optional): dims = [index(X),index(Y),index(Z)] where: 0=x, 1=y, 2=z

Returns: 0 if computation failed

◆ projectPointsOn2DPlane()

template<class Vec2D >

bool CCCoreLib::Neighbourhood::projectPointsOn2DPlane	(	std::vector< Vec2D > &	points2D,
		const PointCoordinateType *	planeEquation = `nullptr`,
		CCVector3 *	O = `nullptr`,
		CCVector3 *	X = `nullptr`,
		CCVector3 *	Y = `nullptr`,
		InputVectorsUsage	vectorsUsage = `None`
	)

inline

Projects points on the best fitting LS plane.

Projected points are stored in the points2D vector.

Parameters

points2D	output set
planeEquation	custom plane equation (otherwise the default Neighbouhood's one is used)
O	if set, the local plane base origin will be output here
X	if set, the local plane base X vector will be output here
Y	if set, the local plane base Y vector will be output here
vectorsUsage	Defines how input vectors should be used

Returns: success

◆ setGravityCenter()

void Neighbourhood::setGravityCenter ( const CCVector3 & G )

Sets gravity center.

Handle with care!

Parameters

G	gravity center

◆ setLSPlane()

void Neighbourhood::setLSPlane	(	const PointCoordinateType	eq[4],
		const CCVector3 &	X,
		const CCVector3 &	Y,
		const CCVector3 &	N
	)

Sets the best interpolating plane equation (Least-square)

Handle with care!

Parameters

eq	plane equation (ax + by + cz = d)
X	local base X vector
Y	local base Y vector
N	normal vector

◆ triangulateOnPlane()

GenericIndexedMesh * Neighbourhood::triangulateOnPlane	(	bool	duplicateVertices,
		PointCoordinateType	maxEdgeLength,
		std::string &	outputErrorStr
	)

Applies 2D Delaunay triangulation.

Cloud selection is first projected on the best least-square plane.

Parameters

duplicateVertices	whether to duplicate vertices (a new point cloud is created) or to use the associated one)
maxEdgeLength	max edge length for output triangles (IGNORE_MAX_EDGE_LENGTH = ignored)
outputErrorStr	error (if any)

Member Data Documentation

◆ m_gravityCenter

CCVector3 CCCoreLib::Neighbourhood::m_gravityCenter

protected

Gravity center.

Only valid if 'structuresValidity & GRAVITY_CENTER != 0'.

◆ m_lsPlaneEquation

PointCoordinateType CCCoreLib::Neighbourhood::m_lsPlaneEquation[4]

protected

Least-square best fitting plane parameters.

Array [a,b,c,d] such that ax+by+cz = d Only valid if 'structuresValidity & LS_PLANE != 0'.

◆ m_lsPlaneVectors

CCVector3 CCCoreLib::Neighbourhood::m_lsPlaneVectors[3]

protected

Least-square best fitting plane base vectors.

Only valid if 'structuresValidity & LS_PLANE != 0'.

◆ m_quadricEquation

PointCoordinateType CCCoreLib::Neighbourhood::m_quadricEquation[6]

protected

2.5D Quadric equation

Array [a,b,c,d,e,f] such that Z = a + b.X + c.Y + d.X^2 + e.X.Y + f.Y^2.

Warning: : 'X','Y' and 'Z' are defined by 'm_quadricEquationDirections' Only valid if 'structuresValidity & QUADRIC != 0'.

◆ m_quadricEquationDirections

Tuple3ub CCCoreLib::Neighbourhood::m_quadricEquationDirections

protected

2.5D Quadric equation dimensions

Array (index(X),index(Y),index(Z)) where: 0=x, 1=y, 2=z Only valid if 'structuresValidity & QUADRIC != 0'.

The documentation for this class was generated from the following files:

Neighbourhood.h
Neighbourhood.cpp

Public Types

Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Member Enumeration Documentation

◆ GeomFeature

Constructor & Destructor Documentation

◆ Neighbourhood()

Member Function Documentation

◆ compute3DQuadric()

◆ computeCurvature()

◆ computeFeature()

◆ computeMomentOrder1()

◆ computeRoughness()

◆ getGravityCenter()

◆ getLSPlane()

◆ getLSPlaneNormal()

◆ getLSPlaneX()

◆ getLSPlaneY()

◆ getQuadric()

◆ projectPointsOn2DPlane()

◆ setGravityCenter()

◆ setLSPlane()

◆ triangulateOnPlane()

Member Data Documentation

◆ m_gravityCenter

◆ m_lsPlaneEquation

◆ m_lsPlaneVectors

◆ m_quadricEquation

◆ m_quadricEquationDirections