A kernel filter implementing a discrete Gaussian distribution in two dimensions. More...

#include <GaussianFilter.h>

Inheritance diagram for pcl::GaussianFilter:

Public Member Functions
	GaussianFilter ()=default

	GaussianFilter (const GaussianFilter &)=default

	GaussianFilter (float sigma, float epsilon, float rho, float theta=0, const String &name=String())

	GaussianFilter (float sigma, float epsilon=0.01, const String &name=String())

	GaussianFilter (GaussianFilter &&)=default

	GaussianFilter (int n, float epsilon, float rho, float theta=0, const String &name=String())

	GaussianFilter (int n, float epsilon=0.01, const String &name=String())

float	AspectRatio () const

SeparableFilter	AsSeparableFilter (float tolerance=__PCL_DEFAULT_FILTER_SEPARABILITY_TOLERANCE) const override

KernelFilter *	Clone () const override

double	FWHM () const

double	FWHMx () const

double	FWHMy () const

bool	IsSeparable () const override

GaussianFilter &	operator= (const GaussianFilter &x)

GaussianFilter &	operator= (GaussianFilter &&x)

void	Resize (int n) override

float	RotationAngle () const

void	Set (float sigma)

void	Set (float sigma, float epsilon)

void	Set (float sigma, float epsilon, float rho)

void	Set (float sigma, float epsilon, float rho, float theta)

void	SetAspectRatio (float rho)

void	SetRotationAngle (float theta)

void	SetSigma (float sigma)

void	SetTruncation (float epsilon)

float	Sigma () const

float	SigmaX () const

float	SigmaY () const

float	Truncation () const

Public Member Functions inherited from pcl::KernelFilter
	KernelFilter (const coefficient_matrix &F, const String &name=String())

	KernelFilter (const KernelFilter &)=default

	KernelFilter (const String &name=String())

template<typename T >
	KernelFilter (const T *k, int n, const String &name=String())

	KernelFilter (int n, const String &name=String())

template<typename T >
	KernelFilter (int n, const T &x, const String &name=String())

	KernelFilter (KernelFilter &&)=default

virtual	~KernelFilter ()

const coefficient *	Begin () const

const coefficient *	begin () const

virtual void	Clear ()

coefficient_matrix	Coefficients () const

const coefficient *	End () const

const coefficient *	end () const

void	Flip ()

KernelFilter	Flipped () const

bool	IsEmpty () const

bool	IsFlipped () const

bool	IsHighPassFilter () const

double	Modulus () const

String	Name () const

void	Normalize ()

KernelFilter	Normalized () const

int	NumberOfCoefficients () const

	operator bool () const

KernelFilter &	operator= (const coefficient &x)

KernelFilter &	operator= (const coefficient_matrix &F)

KernelFilter &	operator= (const KernelFilter &)=default

KernelFilter &	operator= (KernelFilter &&)=default

bool	operator== (const KernelFilter &f) const

const coefficient *	operator[] (int row) const

virtual void	Rename (const String &newName)

bool	SameCoefficients (const KernelFilter &f) const

int	Size () const

template<class P >
void	ToImage (GenericImage< P > &image) const

void	ToImage (ImageVariant &v) const

double	Weight () const

Friends
void	Swap (GaussianFilter &x1, GaussianFilter &x2)

Additional Inherited Members
Public Types inherited from pcl::KernelFilter
using	coefficient = float

using	coefficient_matrix = GenericMatrix< coefficient >

Detailed Description

A GaussianFilter object is a specialized KernelFilter whose elements are calculated as a discrete representation of an elliptical Gaussian function centered at the origin:

G(x,y) = Exp( -( x^2/(2*sx^2) + y^2/(2*sy^2) ) )

where sx and sy are the standard deviations of the Gaussian distribution on the horizontal and vertical axes, respectively.

GaussianFilter also supports arbitrary rotation around the origin. When the filter is rotated, the coordinates x, y in the equation above are replaced by their rotated counterparts.

A GaussianFilter instance is formally defined by the following parameters:

sigma	Standard deviation of the filter distribution on the X axis (sigma > 0).
rho	The ratio sy/sx (see equation above) of the generated filter distribution (0 <= rho <= 1).
theta	Rotation angle of the horizontal axis in radians (0 <= theta < PI). This parameter only makes sense when rho < 1.
epsilon	Maximum truncation error of the computed filter coefficients (eps > 0).

See also: KernelFilter, VariableShapeFilter, MoffatFilter, LinearFilter, MeanFilter

Definition at line 97 of file GaussianFilter.h.

Constructor & Destructor Documentation

◆ GaussianFilter() [1/7]

pcl::GaussianFilter::GaussianFilter ( )

default

Constructs an empty GaussianFilter object with default functional parameters: sigma=2, epsilon=0.01, rho=1, theta=0.

◆ GaussianFilter() [2/7]

pcl::GaussianFilter::GaussianFilter	(	float	sigma,
		float	epsilon = `0.01`,
		const String &	name = `String()`
	)

inline

Constructs a GaussianFilter object given the standard deviation sigma > 0 and truncation error epsilon > 0. Assigns an optional name to the new filter object.

Definition at line 112 of file GaussianFilter.h.

◆ GaussianFilter() [3/7]

pcl::GaussianFilter::GaussianFilter	(	float	sigma,
		float	epsilon,
		float	rho,
		float	theta = `0`,
		const String &	name = `String()`
	)

inline

Constructs a GaussianFilter object given the standard deviation sigma > 0, truncation error epsilon > 0, aspect ratio 0 <= rho <= 1, and rotation angle 0 <= theta <= PI in radians. Assigns an optional name to the new filter object.

Definition at line 124 of file GaussianFilter.h.

◆ GaussianFilter() [4/7]

pcl::GaussianFilter::GaussianFilter	(	int	n,
		float	epsilon = `0.01`,
		const String &	name = `String()`
	)

inline

Constructs a GaussianFilter object given the odd kernel size n >= 3 and truncation error epsilon > 0. Assigns an optional name to the new filter object.

Definition at line 135 of file GaussianFilter.h.

◆ GaussianFilter() [5/7]

pcl::GaussianFilter::GaussianFilter	(	int	n,
		float	epsilon,
		float	rho,
		float	theta = `0`,
		const String &	name = `String()`
	)

inline

Constructs a GaussianFilter object given the odd kernel size n >= 3, truncation error epsilon > 0, aspect ratio 0 <= rho <= 1, and rotation angle 0 <= theta <= PI in radians. Assigns an optional name to the new filter object.

Definition at line 147 of file GaussianFilter.h.

◆ GaussianFilter() [6/7]

pcl::GaussianFilter::GaussianFilter ( const GaussianFilter & )

default

Copy constructor.

◆ GaussianFilter() [7/7]

pcl::GaussianFilter::GaussianFilter ( GaussianFilter && )

default

Move constructor.

Member Function Documentation

◆ AspectRatio()

float pcl::GaussianFilter::AspectRatio ( ) const

inline

Returns the aspect ratio of the filter distribution. This is the ratio vertical:horizontal between filter axes in the range [0,1].

Definition at line 268 of file GaussianFilter.h.

◆ AsSeparableFilter()

SeparableFilter pcl::GaussianFilter::AsSeparableFilter ( float tolerance = __PCL_DEFAULT_FILTER_SEPARABILITY_TOLERANCE ) const

inlineoverridevirtual

Returns a separable filter equivalent to this Gaussian kernel filter.

A Gaussian filter is the only circularly symmetric, two-dimensional separable filter. This reimplementation returns a separable filter only if this object represents an undistorted/unrotated Gaussian function, that is, when its aspect ratio is 1. Otherwise an empty SeparableFilter object is returned since the filter matrix is not separable.

Reimplemented from pcl::KernelFilter.

Definition at line 179 of file GaussianFilter.h.

◆ Clone()

KernelFilter* pcl::GaussianFilter::Clone ( ) const

inlineoverridevirtual

Returns a pointer to a dynamically allocated duplicate of this kernel filter.

Note: All derived classes from KernelFilter must reimplement this virtual member function.

Reimplemented from pcl::KernelFilter.

Definition at line 165 of file GaussianFilter.h.

◆ FWHM()

double pcl::GaussianFilter::FWHM ( ) const

inline

Returns the full width at half maximum, in sigma units, for the horizontal axis of the elliptical Gaussian filter distribution.

This function is an alias to FWHMx().

Definition at line 309 of file GaussianFilter.h.

◆ FWHMx()

double pcl::GaussianFilter::FWHMx ( ) const

inline

Returns the full width at half maximum (FWHM), in sigma units, for the horizontal axis of the elliptical Gaussian filter distribution.

Definition at line 287 of file GaussianFilter.h.

◆ FWHMy()

double pcl::GaussianFilter::FWHMy ( ) const

inline

Returns the full width at half maximum (FWHM), in sigma units, for the vertical axis of the elliptical Gaussian filter distribution.

Definition at line 297 of file GaussianFilter.h.

◆ IsSeparable()

bool pcl::GaussianFilter::IsSeparable ( ) const

inlineoverridevirtual

Returns true iff this filter is separable,

A Gaussian filter is separable. As reimplemented in GaussianFilter, this member function returns true for undistorted/unrotated Gaussian filters, that is, when this object's aspect ratio is 1.

Reimplemented from pcl::KernelFilter.

Definition at line 196 of file GaussianFilter.h.

◆ operator=() [1/2]

GaussianFilter& pcl::GaussianFilter::operator= ( const GaussianFilter & x )

inline

Copy assignment operator. Returns a reference to this object.

Definition at line 204 of file GaussianFilter.h.

◆ operator=() [2/2]

GaussianFilter& pcl::GaussianFilter::operator= ( GaussianFilter && x )

inline

Move assignment operator. Returns a reference to this object.

Definition at line 217 of file GaussianFilter.h.

◆ Resize()

void pcl::GaussianFilter::Resize ( int n )

inlineoverridevirtual

Recalculates filter coefficients for the given odd kernel size n >= 3. This routine computes the required standard deviation to sample the Gaussian function on a matrix of the specified size, preserving the current coefficient truncation, aspect ratio and rotation angle.

Reimplemented from pcl::KernelFilter.

Definition at line 395 of file GaussianFilter.h.

◆ RotationAngle()

float pcl::GaussianFilter::RotationAngle ( ) const

inline

Returns the rotation angle of the filter distribution. This is the rotation angle in radians with respect to the central pixel, in the range [0,+PI].

Definition at line 278 of file GaussianFilter.h.

◆ Set() [1/4]

void pcl::GaussianFilter::Set ( float sigma )

inline

Recalculates filter coefficients for the specified sigma sigma > 0. The current coefficient truncation error, aspect ratio and rotation angle are not changed.

Definition at line 349 of file GaussianFilter.h.

◆ Set() [2/4]

void pcl::GaussianFilter::Set	(	float	sigma,
		float	epsilon
	)

inline

Recalculates filter coefficients for the specified sigma sigma > 0 and truncation error epsilon > 0. Does not change the current aspect ratio and rotation angle.

Definition at line 339 of file GaussianFilter.h.

◆ Set() [3/4]

void pcl::GaussianFilter::Set	(	float	sigma,
		float	epsilon,
		float	rho
	)

inline

Recalculates filter coefficients for the specified sigma sigma > 0, truncation error epsilon > 0, and aspect ratio 0 <= rho <= 1. Does not change the current rotation angle.

Definition at line 329 of file GaussianFilter.h.

◆ Set() [4/4]

void pcl::GaussianFilter::Set	(	float	sigma,
		float	epsilon,
		float	rho,
		float	theta
	)

inline

Recalculates filter coefficients for the specified sigma sigma > 0, truncation error epsilon > 0, aspect ratio 0 <= rho <= 1, and rotation angle 0 <= theta <= PI in radians.

Definition at line 319 of file GaussianFilter.h.

◆ SetAspectRatio()

void pcl::GaussianFilter::SetAspectRatio ( float rho )

inline

This is a convenience member function, equivalent to Set( Sigma(), Truncation(), rho ).

Definition at line 375 of file GaussianFilter.h.

◆ SetRotationAngle()

void pcl::GaussianFilter::SetRotationAngle ( float theta )

inline

This is a convenience member function, equivalent to Set( Sigma(), Truncation(), AspectRatio(), theta ).

Definition at line 384 of file GaussianFilter.h.

◆ SetSigma()

void pcl::GaussianFilter::SetSigma ( float sigma )

inline

This is a convenience member function, equivalent to Set( sigma ).

Definition at line 357 of file GaussianFilter.h.

◆ SetTruncation()

void pcl::GaussianFilter::SetTruncation ( float epsilon )

inline

This is a convenience member function, equivalent to Set( Sigma(), epsilon ).

Definition at line 366 of file GaussianFilter.h.

◆ Sigma()

float pcl::GaussianFilter::Sigma ( ) const

inline

Returns the standard deviation of the filter distribution on the X (horizontal) axis.

This function is an alias to SigmaX().

Definition at line 251 of file GaussianFilter.h.

◆ SigmaX()

float pcl::GaussianFilter::SigmaX ( ) const

inline

Returns the standard deviation of the filter distribution on the X (horizontal) axis.

Definition at line 231 of file GaussianFilter.h.

◆ SigmaY()

float pcl::GaussianFilter::SigmaY ( ) const

inline

Returns the standard deviation of the filter distribution on the Y (vertical) axis.

Definition at line 240 of file GaussianFilter.h.

◆ Truncation()

float pcl::GaussianFilter::Truncation ( ) const

inline

Returns the maximum truncation error of the filter coefficients.

Definition at line 259 of file GaussianFilter.h.

Friends And Related Function Documentation

◆ Swap

void Swap	(	GaussianFilter &	x1,
		GaussianFilter &	x2
	)

friend

Exchanges two Gaussian filters x1 and x2.

Definition at line 403 of file GaussianFilter.h.

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

GaussianFilter.h

Public Member Functions

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ GaussianFilter() [1/7]

◆ GaussianFilter() [2/7]

◆ GaussianFilter() [3/7]

◆ GaussianFilter() [4/7]

◆ GaussianFilter() [5/7]

◆ GaussianFilter() [6/7]

◆ GaussianFilter() [7/7]

Member Function Documentation

◆ AspectRatio()

◆ AsSeparableFilter()

◆ Clone()

◆ FWHM()

◆ FWHMx()

◆ FWHMy()

◆ IsSeparable()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ Resize()

◆ RotationAngle()

◆ Set() [1/4]

◆ Set() [2/4]

◆ Set() [3/4]

◆ Set() [4/4]

◆ SetAspectRatio()

◆ SetRotationAngle()

◆ SetSigma()

◆ SetTruncation()

◆ Sigma()

◆ SigmaX()

◆ SigmaY()

◆ Truncation()

Friends And Related Function Documentation

◆ Swap