Detailed Description

A generic 2D feature from an image, extracted with CFeatureExtraction Each feature may have one or more descriptors (see descriptors), in addition to an image patch.

The (Euclidean) distance between descriptors in a pair of features can be computed with descriptorDistanceTo, while the similarity of the patches is given by patchCorrelationTo.

See Also: CFeatureList, TSimpleFeature, TSimpleFeatureList

Definition at line 78 of file CFeature.h.

#include <mrpt/vision/CFeature.h>

Inheritance diagram for mrpt::vision::CFeature:

[legend]

Classes
struct	TDescriptors
	All the possible descriptors this feature may have. More...

Public Member Functions
bool	isPointFeature () const
	Return false only for Blob detectors (SIFT, SURF)

bool	getFirstDescriptorAsMatrix (mrpt::math::CMatrixFloat &desc) const
	Return the first found descriptor, as a matrix.

float	patchCorrelationTo (const CFeature &oFeature) const
	Computes the normalized cross-correlation between the patches of this and another feature (normalized in the range [0,1], such as 0=best, 1=worst).

float	descriptorDistanceTo (const CFeature &oFeature, TDescriptorType descriptorToUse=descAny, bool normalize_distances=true) const
	Computes the Euclidean Distance between this feature's and other feature's descriptors, using the given descriptor or the first present one.

float	descriptorSIFTDistanceTo (const CFeature &oFeature, bool normalize_distances=true) const
	Computes the Euclidean Distance between "this" and the "other" descriptors.

float	descriptorSURFDistanceTo (const CFeature &oFeature, bool normalize_distances=true) const
	Computes the Euclidean Distance between "this" and the "other" descriptors.

float	descriptorSpinImgDistanceTo (const CFeature &oFeature, bool normalize_distances=true) const
	Computes the Euclidean Distance between "this" and the "other" descriptors.

float	descriptorPolarImgDistanceTo (const CFeature &oFeature, float &minDistAngle, bool normalize_distances=true) const
	Returns the minimum Euclidean Distance between "this" and the "other" polar image descriptor, for the best shift in orientation.

float	descriptorLogPolarImgDistanceTo (const CFeature &oFeature, float &minDistAngle, bool normalize_distances=true) const
	Returns the minimum Euclidean Distance between "this" and the "other" log-polar image descriptor, for the best shift in orientation.

void	saveToTextFile (const std::string &filename, bool APPEND=false)
	Save the feature to a text file in this format: "%% Dump of mrpt::vision::CFeatureList. Each line format is:\n" "%% ID TYPE X Y ORIENTATION SCALE TRACK_STATUS RESPONSE HAS_SIFT [SIFT] HAS_SURF [SURF] HAS_MULTI [MULTI]_i" "%% \|-------------------— feature ---------------—\| \|-------------------— descriptors ---------------------—\|" "%% with:\n" "%% TYPE : The used detector: 0:KLT, 1: Harris, 2: BCD, 3: SIFT, 4: SURF, 5: Beacon, 6: FAST\n" "%% HAS_* : 1 if a descriptor of that type is associated to the feature." "%% SIFT : Present if HAS_SIFT=1: N DESC_0 ... DESC_N-1" "%% SURF : Present if HAS_SURF=1: N DESC_0 ... DESC_N-1" "%% MULTI : Present if HAS_MULTI=1: SCALE ORI N DESC_0 ... DESC_N-1" "%%----------------------------------------------------------------------------------------—\n");

TFeatureType	get_type () const
	Get the type of the feature.

void	dumpToTextStream (mrpt::utils::CStream &out) const
	Dump feature information into a text stream.

void	dumpToConsole () const

	CFeature ()
	Constructor.

virtual	~CFeature ()
	Virtual destructor.

mrpt::utils::CObjectPtr	duplicateGetSmartPtr () const
	Returns a copy of the object, indepently of its class, as a smart pointer (the newly created object will exist as long as any copy of this smart pointer).

CObject *	clone () const
	Cloning interface for smart pointers.

Public Attributes
float	x

float	y
	Coordinates in the image.

TFeatureID	ID
	ID of the feature.

CImage	patch
	A patch of the image surrounding the feature.

uint16_t	patchSize
	Size of the patch (patchSize x patchSize) (it must be an odd number)

TFeatureType	type
	Type of the feature: featNotDefined, featSIFT, featKLT, featHarris, featSURF, featBeacon.

TFeatureTrackStatus	track_status
	Status of the feature tracking process (old name: KLT_status)

float	response
	A measure of the "goodness" of the feature (old name: KLT_val)

float	orientation
	Main orientation of the feature.

float	scale
	Feature scale into the scale space.

uint8_t	user_flags
	A field for any other flags needed by the user (this has not a predefined meaning)

uint16_t	nTimesSeen
	Number of frames it has been seen in a sequence of images.

uint16_t	nTimesNotSeen
	Number of frames it has not been seen in a sequence of images.

uint16_t	nTimesLastSeen
	Number of frames since it was seen for the last time.

double	depth
	The estimated depth in 3D of this feature wrt the camera in the current frame.

double	initialDepth
	The estimated depth in 3D of this feature wrt the camera that took its image.

TPoint3D	p3D
	The estimated 3D point of this feature wrt its camera.

deque< double >	multiScales
	A set of scales where the multi-resolution descriptor has been computed.

deque< vector< double > >	multiOrientations
	A vector of main orientations (there is a vector of orientations for each scale)

deque< vector< vector< int32_t > > >	multiHashCoeffs
	A set of vectors containing the coefficients for a HASH table of descriptors.

struct VISION_IMPEXP mrpt::vision::CFeature::TDescriptors	descriptors

Static Public Attributes
static const mrpt::utils::TRuntimeClassId	classCObject

RTTI stuff
static const mrpt::utils::TRuntimeClassId	classCSerializable

Protected Member Functions
CSerializable virtual methods
void	writeToStream (mrpt::utils::CStream &out, int *getVersion) const
	Introduces a pure virtual method responsible for writing to a CStream.

void	readFromStream (mrpt::utils::CStream &in, int version)
	Introduces a pure virtual method responsible for loading from a CStream This can not be used directly be users, instead use "stream >> object;" for reading it from a stream or "stream >> object_ptr;" if the class is unknown apriori.

Static Protected Member Functions
static float	internal_distanceBetweenPolarImages (const mrpt::math::CMatrix &desc1, const mrpt::math::CMatrix &desc2, float &minDistAngle, bool normalize_distances, bool dont_shift_angle)
	Internal function used by "descriptorLogPolarImgDistanceTo" and "descriptorPolarImgDistanceTo".

Friends
class	CFeatureList

class	CMatchedFeatureList

RTTI stuff
typedef CFeaturePtr	SmartPtr

static mrpt::utils::CLASSINIT	_init_CFeature

static mrpt::utils::TRuntimeClassId	classCFeature

static const mrpt::utils::TRuntimeClassId *	classinfo

static const mrpt::utils::TRuntimeClassId *	_GetBaseClass ()

virtual const mrpt::utils::TRuntimeClassId *	GetRuntimeClass () const
	Returns information about the class of an object in runtime.

virtual mrpt::utils::CObject *	duplicate () const
	Returns a copy of the object, indepently of its class.

static mrpt::utils::CObject *	CreateObject ()

static CFeaturePtr	Create ()

Member Typedef Documentation

typedef CFeaturePtr mrpt::vision::CFeature::SmartPtr

A typedef for the associated smart pointer

Definition at line 83 of file CFeature.h.

Constructor & Destructor Documentation

mrpt::vision::CFeature::CFeature ( )

Constructor.

virtual mrpt::vision::CFeature::~CFeature ( )

inlinevirtual

Virtual destructor.

Definition at line 207 of file CFeature.h.

Member Function Documentation

static const mrpt::utils::TRuntimeClassId* mrpt::vision::CFeature::_GetBaseClass ( )

staticprotected

CObject* mrpt::utils::CObject::clone ( ) const

inlineinherited

Cloning interface for smart pointers.

Definition at line 154 of file CObject.h.

static CFeaturePtr mrpt::vision::CFeature::Create ( )

static

static mrpt::utils::CObject* mrpt::vision::CFeature::CreateObject ( )

static

float mrpt::vision::CFeature::descriptorDistanceTo	(	const CFeature &	oFeature,
		TDescriptorType	descriptorToUse = `descAny`,
		bool	normalize_distances = `true`
	)		const

Computes the Euclidean Distance between this feature's and other feature's descriptors, using the given descriptor or the first present one.

Note: If descriptorToUse is not descAny and that descriptor is not present in one of the features, an exception will be raised.

See Also: patchCorrelationTo

float mrpt::vision::CFeature::descriptorLogPolarImgDistanceTo	(	const CFeature &	oFeature,
		float &	minDistAngle,
		bool	normalize_distances = `true`
	)		const

Returns the minimum Euclidean Distance between "this" and the "other" log-polar image descriptor, for the best shift in orientation.

Parameters

oFeature	The other feature to compare with.
minDistAngle	The placeholder for the angle at which the smallest distance is found.

Returns: The distance for the best orientation (minimum distance).

float mrpt::vision::CFeature::descriptorPolarImgDistanceTo	(	const CFeature &	oFeature,
		float &	minDistAngle,
		bool	normalize_distances = `true`
	)		const

Returns the minimum Euclidean Distance between "this" and the "other" polar image descriptor, for the best shift in orientation.

Parameters

oFeature	The other feature to compare with.
minDistAngle	The placeholder for the angle at which the smallest distance is found.

Returns: The distance for the best orientation (minimum distance).

float mrpt::vision::CFeature::descriptorSIFTDistanceTo	(	const CFeature &	oFeature,
		bool	normalize_distances = `true`
	)		const

Computes the Euclidean Distance between "this" and the "other" descriptors.

float mrpt::vision::CFeature::descriptorSpinImgDistanceTo	(	const CFeature &	oFeature,
		bool	normalize_distances = `true`
	)		const

Computes the Euclidean Distance between "this" and the "other" descriptors.

float mrpt::vision::CFeature::descriptorSURFDistanceTo	(	const CFeature &	oFeature,
		bool	normalize_distances = `true`
	)		const

Computes the Euclidean Distance between "this" and the "other" descriptors.

void mrpt::vision::CFeature::dumpToConsole ( ) const

void mrpt::vision::CFeature::dumpToTextStream ( mrpt::utils::CStream & out ) const

Dump feature information into a text stream.

virtual mrpt::utils::CObject* mrpt::vision::CFeature::duplicate ( ) const

virtual

Returns a copy of the object, indepently of its class.

Implements mrpt::utils::CObject.

mrpt::utils::CObjectPtr mrpt::utils::CObject::duplicateGetSmartPtr ( ) const

inlineinherited

Returns a copy of the object, indepently of its class, as a smart pointer (the newly created object will exist as long as any copy of this smart pointer).

Definition at line 151 of file CObject.h.

TFeatureType mrpt::vision::CFeature::get_type ( ) const

inline

Get the type of the feature.

Definition at line 195 of file CFeature.h.

bool mrpt::vision::CFeature::getFirstDescriptorAsMatrix ( mrpt::math::CMatrixFloat & desc ) const

Return the first found descriptor, as a matrix.

Returns: false on error, i.e. there is no valid descriptor.

virtual const mrpt::utils::TRuntimeClassId* mrpt::vision::CFeature::GetRuntimeClass ( ) const

virtual

Returns information about the class of an object in runtime.

Reimplemented from mrpt::utils::CSerializable.

static float mrpt::vision::CFeature::internal_distanceBetweenPolarImages	(	const mrpt::math::CMatrix &	desc1,
		const mrpt::math::CMatrix &	desc2,
		float &	minDistAngle,
		bool	normalize_distances,
		bool	dont_shift_angle
	)

staticprotected

Internal function used by "descriptorLogPolarImgDistanceTo" and "descriptorPolarImgDistanceTo".

bool mrpt::vision::CFeature::isPointFeature ( ) const

Return false only for Blob detectors (SIFT, SURF)

float mrpt::vision::CFeature::patchCorrelationTo ( const CFeature & oFeature ) const

Computes the normalized cross-correlation between the patches of this and another feature (normalized in the range [0,1], such as 0=best, 1=worst).

Note: If this or the other features does not have patches or they are of different sizes, an exception will be raised.

See Also: descriptorDistanceTo

void mrpt::vision::CFeature::readFromStream	(	mrpt::utils::CStream &	in,
		int	version
	)

protectedvirtual

Introduces a pure virtual method responsible for loading from a CStream This can not be used directly be users, instead use "stream >> object;" for reading it from a stream or "stream >> object_ptr;" if the class is unknown apriori.

Parameters

in	The input binary stream where the object data must read from.
version	The version of the object stored in the stream: use this version number in your code to know how to read the incoming data.

Exceptions

std::exception On any error, see CStream::ReadBuffer

See Also: CStream

Implements mrpt::utils::CSerializable.

void mrpt::vision::CFeature::saveToTextFile	(	const std::string &	filename,
		bool	APPEND = `false`
	)

     Save the feature to a text file in this format:

"%% Dump of mrpt::vision::CFeatureList. Each line format is:\n" "%% ID TYPE X Y ORIENTATION SCALE TRACK_STATUS RESPONSE HAS_SIFT [SIFT] HAS_SURF [SURF] HAS_MULTI [MULTI]_i" "%% |-------------------— feature ---------------—| |-------------------— descriptors ---------------------—|" "%% with:\n" "%% TYPE : The used detector: 0:KLT, 1: Harris, 2: BCD, 3: SIFT, 4: SURF, 5: Beacon, 6: FAST\n" "%% HAS_* : 1 if a descriptor of that type is associated to the feature." "%% SIFT : Present if HAS_SIFT=1: N DESC_0 ... DESC_N-1" "%% SURF : Present if HAS_SURF=1: N DESC_0 ... DESC_N-1" "%% MULTI : Present if HAS_MULTI=1: SCALE ORI N DESC_0 ... DESC_N-1" "%%----------------------------------------------------------------------------------------—\n");

void mrpt::vision::CFeature::writeToStream	(	mrpt::utils::CStream &	out,
		int *	getVersion
	)		const

protectedvirtual

Introduces a pure virtual method responsible for writing to a CStream.

This can not be used directly be users, instead use "stream << object;" for writing it to a stream.

Parameters

out	The output binary stream where object must be dumped.
getVersion	If NULL, the object must be dumped. If not, only the version of the object dump must be returned in this pointer. This enables the versioning of objects dumping and backward compatibility with previously stored data.

Exceptions

std::exception On any error, see CStream::WriteBuffer

See Also: CStream

Implements mrpt::utils::CSerializable.

Friends And Related Function Documentation

friend class CFeatureList

friend

Definition at line 80 of file CFeature.h.

friend class CMatchedFeatureList

friend

Definition at line 81 of file CFeature.h.

Member Data Documentation

mrpt::utils::CLASSINIT mrpt::vision::CFeature::_init_CFeature

staticprotected

Definition at line 83 of file CFeature.h.

mrpt::utils::TRuntimeClassId mrpt::vision::CFeature::classCFeature

static

Definition at line 83 of file CFeature.h.

const mrpt::utils::TRuntimeClassId mrpt::utils::CObject::classCObject

staticinherited

Definition at line 139 of file CObject.h.

const mrpt::utils::TRuntimeClassId mrpt::utils::CSerializable::classCSerializable

staticinherited

Definition at line 56 of file CSerializable.h.

const mrpt::utils::TRuntimeClassId* mrpt::vision::CFeature::classinfo

static

Definition at line 83 of file CFeature.h.

double mrpt::vision::CFeature::depth

The estimated depth in 3D of this feature wrt the camera in the current frame.

Definition at line 100 of file CFeature.h.

struct VISION_IMPEXP mrpt::vision::CFeature::TDescriptors mrpt::vision::CFeature::descriptors

TFeatureID mrpt::vision::CFeature::ID

ID of the feature.

Definition at line 87 of file CFeature.h.

double mrpt::vision::CFeature::initialDepth

The estimated depth in 3D of this feature wrt the camera that took its image.

Definition at line 101 of file CFeature.h.

deque<vector<vector<int32_t> > > mrpt::vision::CFeature::multiHashCoeffs

A set of vectors containing the coefficients for a HASH table of descriptors.

Definition at line 105 of file CFeature.h.

deque<vector<double> > mrpt::vision::CFeature::multiOrientations

A vector of main orientations (there is a vector of orientations for each scale)

Definition at line 104 of file CFeature.h.

deque<double> mrpt::vision::CFeature::multiScales

A set of scales where the multi-resolution descriptor has been computed.

Definition at line 103 of file CFeature.h.

uint16_t mrpt::vision::CFeature::nTimesLastSeen

Number of frames since it was seen for the last time.

Definition at line 98 of file CFeature.h.

uint16_t mrpt::vision::CFeature::nTimesNotSeen

Number of frames it has not been seen in a sequence of images.

Definition at line 97 of file CFeature.h.

uint16_t mrpt::vision::CFeature::nTimesSeen

Number of frames it has been seen in a sequence of images.

Definition at line 96 of file CFeature.h.

float mrpt::vision::CFeature::orientation

Main orientation of the feature.

Definition at line 93 of file CFeature.h.

TPoint3D mrpt::vision::CFeature::p3D

The estimated 3D point of this feature wrt its camera.

Definition at line 102 of file CFeature.h.

CImage mrpt::vision::CFeature::patch

A patch of the image surrounding the feature.

Definition at line 88 of file CFeature.h.

uint16_t mrpt::vision::CFeature::patchSize

Size of the patch (patchSize x patchSize) (it must be an odd number)

Definition at line 89 of file CFeature.h.

float mrpt::vision::CFeature::response

A measure of the "goodness" of the feature (old name: KLT_val)

Definition at line 92 of file CFeature.h.

float mrpt::vision::CFeature::scale

Feature scale into the scale space.

Definition at line 94 of file CFeature.h.

TFeatureTrackStatus mrpt::vision::CFeature::track_status

Status of the feature tracking process (old name: KLT_status)

Definition at line 91 of file CFeature.h.

TFeatureType mrpt::vision::CFeature::type

Type of the feature: featNotDefined, featSIFT, featKLT, featHarris, featSURF, featBeacon.

Definition at line 90 of file CFeature.h.

uint8_t mrpt::vision::CFeature::user_flags

A field for any other flags needed by the user (this has not a predefined meaning)

Definition at line 95 of file CFeature.h.

float mrpt::vision::CFeature::x

Definition at line 86 of file CFeature.h.

float mrpt::vision::CFeature::y

Coordinates in the image.

Definition at line 86 of file CFeature.h.

Detailed Description

Classes

Public Member Functions

Public Attributes

Static Public Attributes

Protected Member Functions

Static Protected Member Functions

Friends

RTTI stuff

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation