Maximally stable extremal region extractor. More...

#include <opencv2/features2d.hpp>

Inheritance diagram for cv::MSER:

Collaboration diagram for cv::MSER:

Public Member Functions
virtual void	clear ()
	Clears the algorithm state. More...

virtual void	compute (InputArray image, std::vector< KeyPoint > &keypoints, OutputArray descriptors)
	Computes the descriptors for a set of keypoints detected in an image (first variant) or image set (second variant). More...

virtual void	compute (InputArrayOfArrays images, std::vector< std::vector< KeyPoint > > &keypoints, OutputArrayOfArrays descriptors)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...

virtual int	defaultNorm () const

virtual int	descriptorSize () const

virtual int	descriptorType () const

virtual void	detect (InputArray image, std::vector< KeyPoint > &keypoints, InputArray mask=noArray())
	Detects keypoints in an image (first variant) or image set (second variant). More...

virtual void	detect (InputArrayOfArrays images, std::vector< std::vector< KeyPoint > > &keypoints, InputArrayOfArrays masks=noArray())
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...

virtual void	detectAndCompute (InputArray image, InputArray mask, std::vector< KeyPoint > &keypoints, OutputArray descriptors, bool useProvidedKeypoints=false)
	Detects keypoints and computes the descriptors. More...

virtual void	detectRegions (InputArray image, std::vector< std::vector< Point > > &msers, std::vector< Rect > &bboxes)=0
	Detect MSER regions. More...

virtual bool	empty () const CV_OVERRIDE
	Return true if detector object is empty. More...

virtual String	getDefaultName () const CV_OVERRIDE
	Returns the algorithm string identifier. More...

virtual int	getDelta () const =0

virtual int	getMaxArea () const =0

virtual int	getMinArea () const =0

virtual bool	getPass2Only () const =0

void	read (const String &fileName)

virtual void	read (const FileNode &) CV_OVERRIDE
	Reads algorithm parameters from a file storage. More...

virtual void	save (const String &filename) const
	Saves the algorithm to a file. More...

virtual void	setDelta (int delta)=0

virtual void	setMaxArea (int maxArea)=0

virtual void	setMinArea (int minArea)=0

virtual void	setPass2Only (bool f)=0

void	write (const String &fileName) const

virtual void	write (FileStorage &) const CV_OVERRIDE
	Stores algorithm parameters in a file storage. More...

void	write (const Ptr< FileStorage > &fs, const String &name=String()) const

Static Public Member Functions
static Ptr< MSER >	create (int _delta=5, int _min_area=60, int _max_area=14400, double _max_variation=0.25, double _min_diversity=.2, int _max_evolution=200, double _area_threshold=1.01, double _min_margin=0.003, int _edge_blur_size=5)
	Full consturctor for MSER detector. More...

template<typename _Tp >
static Ptr< _Tp >	load (const String &filename, const String &objname=String())
	Loads algorithm from the file. More...

template<typename _Tp >
static Ptr< _Tp >	loadFromString (const String &strModel, const String &objname=String())
	Loads algorithm from a String. More...

Protected Member Functions
void	writeFormat (FileStorage &fs) const

Detailed Description

Maximally stable extremal region extractor.

The class encapsulates all the parameters of the MSER extraction algorithm (see wiki article).

there are two different implementation of MSER: one for grey image, one for color image
the grey image algorithm is taken from: [70] ; the paper claims to be faster than union-find method; it actually get 1.5~2m/s on my centrino L7200 1.2GHz laptop.
the color image algorithm is taken from: [34] ; it should be much slower than grey image method ( 3~4 times ); the chi_table.h file is taken directly from paper's source code which is distributed under GPL.
(Python) A complete example showing the use of the MSER detector can be found at samples/python/mser.py

Member Function Documentation

◆ clear()

virtual void cv::Algorithm::clear ( )

inlinevirtualinherited

Clears the algorithm state.

Reimplemented in cv::FlannBasedMatcher, and cv::DescriptorMatcher.

◆ compute() [1/2]

virtual void cv::Feature2D::compute	(	InputArray	image,
		std::vector< KeyPoint > &	keypoints,
		OutputArray	descriptors
	)

virtualinherited

Computes the descriptors for a set of keypoints detected in an image (first variant) or image set (second variant).

Parameters

image	Image.
keypoints	Input collection of keypoints. Keypoints for which a descriptor cannot be computed are removed. Sometimes new keypoints can be added, for example: SIFT duplicates keypoint with several dominant orientations (for each orientation).
descriptors	Computed descriptors. In the second variant of the method descriptors[i] are descriptors computed for a keypoints[i]. Row j is the keypoints (or keypoints[i]) is the descriptor for keypoint j-th keypoint.

◆ compute() [2/2]

virtual void cv::Feature2D::compute	(	InputArrayOfArrays	images,
		std::vector< std::vector< KeyPoint > > &	keypoints,
		OutputArrayOfArrays	descriptors
	)

virtualinherited

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters

images	Image set.
keypoints	Input collection of keypoints. Keypoints for which a descriptor cannot be computed are removed. Sometimes new keypoints can be added, for example: SIFT duplicates keypoint with several dominant orientations (for each orientation).
descriptors	Computed descriptors. In the second variant of the method descriptors[i] are descriptors computed for a keypoints[i]. Row j is the keypoints (or keypoints[i]) is the descriptor for keypoint j-th keypoint.

◆ create()

static Ptr<MSER> cv::MSER::create	(	int	_delta = `5`,
		int	_min_area = `60`,
		int	_max_area = `14400`,
		double	_max_variation = `0.25`,
		double	_min_diversity = `.2`,
		int	_max_evolution = `200`,
		double	_area_threshold = `1.01`,
		double	_min_margin = `0.003`,
		int	_edge_blur_size = `5`
	)

static

Full consturctor for MSER detector.

Parameters

_delta	it compares \((size_{i}-size_{i-delta})/size_{i-delta}\)
_min_area	prune the area which smaller than minArea
_max_area	prune the area which bigger than maxArea
_max_variation	prune the area have similar size to its children
_min_diversity	for color image, trace back to cut off mser with diversity less than min_diversity
_max_evolution	for color image, the evolution steps
_area_threshold	for color image, the area threshold to cause re-initialize
_min_margin	for color image, ignore too small margin
_edge_blur_size	for color image, the aperture size for edge blur

◆ defaultNorm()

virtual int cv::Feature2D::defaultNorm ( ) const

virtualinherited

◆ descriptorSize()

virtual int cv::Feature2D::descriptorSize ( ) const

virtualinherited

◆ descriptorType()

virtual int cv::Feature2D::descriptorType ( ) const

virtualinherited

◆ detect() [1/2]

virtual void cv::Feature2D::detect	(	InputArray	image,
		std::vector< KeyPoint > &	keypoints,
		InputArray	mask = `noArray()`
	)

virtualinherited

Detects keypoints in an image (first variant) or image set (second variant).

Parameters

image	Image.
keypoints	The detected keypoints. In the second variant of the method keypoints[i] is a set of keypoints detected in images[i] .
mask	Mask specifying where to look for keypoints (optional). It must be a 8-bit integer matrix with non-zero values in the region of interest.

◆ detect() [2/2]

virtual void cv::Feature2D::detect	(	InputArrayOfArrays	images,
		std::vector< std::vector< KeyPoint > > &	keypoints,
		InputArrayOfArrays	masks = `noArray()`
	)

virtualinherited

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters

images	Image set.
keypoints	The detected keypoints. In the second variant of the method keypoints[i] is a set of keypoints detected in images[i] .
masks	Masks for each input image specifying where to look for keypoints (optional). masks[i] is a mask for images[i].

◆ detectAndCompute()

virtual void cv::Feature2D::detectAndCompute	(	InputArray	image,
		InputArray	mask,
		std::vector< KeyPoint > &	keypoints,
		OutputArray	descriptors,
		bool	useProvidedKeypoints = `false`
	)

virtualinherited

Detects keypoints and computes the descriptors.

◆ detectRegions()

virtual void cv::MSER::detectRegions	(	InputArray	image,
		std::vector< std::vector< Point > > &	msers,
		std::vector< Rect > &	bboxes
	)

pure virtual

Detect MSER regions.

Parameters

image	input image (8UC1, 8UC3 or 8UC4, must be greater or equal than 3x3)
msers	resulting list of point sets
bboxes	resulting bounding boxes

◆ empty()

virtual bool cv::Feature2D::empty ( ) const

virtualinherited

Return true if detector object is empty.

Reimplemented from cv::Algorithm.

◆ getDefaultName()

virtual String cv::MSER::getDefaultName ( ) const

virtual

Returns the algorithm string identifier.

This string is used as top level xml/yml node tag when the object is saved to a file or string.

Reimplemented from cv::Feature2D.

◆ getDelta()

virtual int cv::MSER::getDelta ( ) const

pure virtual

◆ getMaxArea()

virtual int cv::MSER::getMaxArea ( ) const

pure virtual

◆ getMinArea()

virtual int cv::MSER::getMinArea ( ) const

pure virtual

◆ getPass2Only()

virtual bool cv::MSER::getPass2Only ( ) const

pure virtual

◆ load()

template<typename _Tp >

static Ptr<_Tp> cv::Algorithm::load	(	const String &	filename,
		const String &	objname = `String()`
	)

inlinestaticinherited

Loads algorithm from the file.

Parameters

filename	Name of the file to read.
objname	The optional name of the node to read (if empty, the first top-level node will be used)

This is static template method of Algorithm. It's usage is following (in the case of SVM):

Ptr<SVM> svm = Algorithm::load<SVM>("my_svm_model.xml");

In order to make this method work, the derived class must overwrite Algorithm::read(const FileNode& fn).

References CV_Assert, cv::FileNode::empty(), cv::FileStorage::getFirstTopLevelNode(), cv::FileStorage::isOpened(), and cv::FileStorage::READ.

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◆ loadFromString()

template<typename _Tp >

static Ptr<_Tp> cv::Algorithm::loadFromString	(	const String &	strModel,
		const String &	objname = `String()`
	)

inlinestaticinherited

Loads algorithm from a String.

Parameters

strModel	The string variable containing the model you want to load.
objname	The optional name of the node to read (if empty, the first top-level node will be used)

This is static template method of Algorithm. It's usage is following (in the case of SVM):

Ptr<SVM> svm = Algorithm::loadFromString<SVM>(myStringModel);

References CV_WRAP, cv::FileNode::empty(), cv::FileStorage::getFirstTopLevelNode(), cv::FileStorage::MEMORY, and cv::FileStorage::READ.

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◆ read() [1/2]

void cv::Feature2D::read ( const String & fileName )

inherited

◆ read() [2/2]

virtual void cv::Feature2D::read ( const FileNode & fn )

virtualinherited

Reads algorithm parameters from a file storage.

Reimplemented from cv::Algorithm.

◆ save()

virtual void cv::Algorithm::save ( const String & filename ) const

virtualinherited

Saves the algorithm to a file.

In order to make this method work, the derived class must implement Algorithm::write(FileStorage& fs).

◆ setDelta()

virtual void cv::MSER::setDelta ( int delta )

pure virtual

◆ setMaxArea()

virtual void cv::MSER::setMaxArea ( int maxArea )

pure virtual

◆ setMinArea()

virtual void cv::MSER::setMinArea ( int minArea )

pure virtual

◆ setPass2Only()

virtual void cv::MSER::setPass2Only ( bool f )

pure virtual

◆ write() [1/3]

void cv::Feature2D::write ( const String & fileName ) const

inherited

◆ write() [2/3]

virtual void cv::Feature2D::write ( FileStorage & fs ) const

virtualinherited

Stores algorithm parameters in a file storage.

Reimplemented from cv::Algorithm.

◆ write() [3/3]

void cv::Feature2D::write	(	const Ptr< FileStorage > &	fs,
		const String &	name = `String()`
	)		const

inlineinherited

References cv::Algorithm::write().

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◆ writeFormat()

void cv::Algorithm::writeFormat ( FileStorage & fs ) const

protectedinherited

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

opencv2/features2d.hpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Member Function Documentation

◆ clear()

◆ compute() [1/2]

◆ compute() [2/2]

◆ create()

◆ defaultNorm()

◆ descriptorSize()

◆ descriptorType()

◆ detect() [1/2]

◆ detect() [2/2]

◆ detectAndCompute()

◆ detectRegions()

◆ empty()

◆ getDefaultName()

◆ getDelta()

◆ getMaxArea()

◆ getMinArea()

◆ getPass2Only()

◆ load()

◆ loadFromString()

◆ read() [1/2]

◆ read() [2/2]

◆ save()

◆ setDelta()

◆ setMaxArea()

◆ setMinArea()

◆ setPass2Only()

◆ write() [1/3]

◆ write() [2/3]

◆ write() [3/3]

◆ writeFormat()