Line segment detector class. More...

#include <opencv2/imgproc.hpp>

Inheritance diagram for cv::LineSegmentDetector:

Collaboration diagram for cv::LineSegmentDetector:

Public Member Functions
virtual	~LineSegmentDetector ()

virtual void	clear ()
	Clears the algorithm state. More...

virtual int	compareSegments (const Size &size, InputArray lines1, InputArray lines2, InputOutputArray _image=noArray())=0
	Draws two groups of lines in blue and red, counting the non overlapping (mismatching) pixels. More...

virtual void	detect (InputArray _image, OutputArray _lines, OutputArray width=noArray(), OutputArray prec=noArray(), OutputArray nfa=noArray())=0
	Finds lines in the input image. More...

virtual void	drawSegments (InputOutputArray _image, InputArray lines)=0
	Draws the line segments on a given image. More...

virtual bool	empty () const
	Returns true if the Algorithm is empty (e.g. More...

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

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

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

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

void	write (const Ptr< FileStorage > &fs, const String &name=String()) const
	simplified API for language bindings This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...

Static Public Member Functions
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...

template<typename _Tp >
static Ptr< _Tp >	read (const FileNode &fn)
	Reads algorithm from the file node. More...

Protected Member Functions
void	writeFormat (FileStorage &fs) const

Detailed Description

Line segment detector class.

following the algorithm described at [102] .

Note: Implementation has been removed due original code license conflict

Constructor & Destructor Documentation

◆ ~LineSegmentDetector()

virtual cv::LineSegmentDetector::~LineSegmentDetector ( )

inlinevirtual

References cv::createLineSegmentDetector(), CV_32F, CV_64F, CV_EXPORTS_W, CV_PI, cv::getDerivKernels(), cv::getGaborKernel(), cv::getGaussianKernel(), cv::LSD_REFINE_STD, and cv::normalize().

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Member Function Documentation

◆ clear()

virtual void cv::Algorithm::clear ( )

inlinevirtualinherited

Clears the algorithm state.

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

◆ compareSegments()

virtual int cv::LineSegmentDetector::compareSegments	(	const Size &	size,
		InputArray	lines1,
		InputArray	lines2,
		InputOutputArray	_image = `noArray()`
	)

pure virtual

Draws two groups of lines in blue and red, counting the non overlapping (mismatching) pixels.

Parameters

size	The size of the image, where lines1 and lines2 were found.
lines1	The first group of lines that needs to be drawn. It is visualized in blue color.
lines2	The second group of lines. They visualized in red color.
_image	Optional image, where the lines will be drawn. The image should be color(3-channel) in order for lines1 and lines2 to be drawn in the above mentioned colors.

◆ detect()

virtual void cv::LineSegmentDetector::detect	(	InputArray	_image,
		OutputArray	_lines,
		OutputArray	width = `noArray()`,
		OutputArray	prec = `noArray()`,
		OutputArray	nfa = `noArray()`
	)

pure virtual

Finds lines in the input image.

This is the output of the default parameters of the algorithm on the above shown image.

image

Parameters

_image	A grayscale (CV_8UC1) input image. If only a roi needs to be selected, use: `lsd_ptr-\>detect(image(roi), lines, ...); lines += Scalar(roi.x, roi.y, roi.x, roi.y);`
_lines	A vector of Vec4i or Vec4f elements specifying the beginning and ending point of a line. Where Vec4i/Vec4f is (x1, y1, x2, y2), point 1 is the start, point 2 - end. Returned lines are strictly oriented depending on the gradient.
width	Vector of widths of the regions, where the lines are found. E.g. Width of line.
prec	Vector of precisions with which the lines are found.
nfa	Vector containing number of false alarms in the line region, with precision of 10%. The bigger the value, logarithmically better the detection. -1 corresponds to 10 mean false alarms 0 corresponds to 1 mean false alarm 1 corresponds to 0.1 mean false alarms This vector will be calculated only when the objects type is LSD_REFINE_ADV.

◆ drawSegments()

virtual void cv::LineSegmentDetector::drawSegments	(	InputOutputArray	_image,
		InputArray	lines
	)

pure virtual

Draws the line segments on a given image.

Parameters

_image	The image, where the lines will be drawn. Should be bigger or equal to the image, where the lines were found.
lines	A vector of the lines that needed to be drawn.

◆ empty()

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

inlinevirtualinherited

Returns true if the Algorithm is empty (e.g.

in the very beginning or after unsuccessful read

Reimplemented in cv::DescriptorMatcher, cv::ml::StatModel, cv::Feature2D, and cv::BaseCascadeClassifier.

◆ getDefaultName()

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

virtualinherited

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 in cv::AKAZE, cv::KAZE, cv::SimpleBlobDetector, cv::GFTTDetector, cv::AgastFeatureDetector, cv::FastFeatureDetector, cv::MSER, cv::ORB, cv::BRISK, and cv::Feature2D.

◆ 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]

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

inlinevirtualinherited

Reads algorithm parameters from a file storage.

Reimplemented in cv::FlannBasedMatcher, cv::DescriptorMatcher, and cv::Feature2D.

◆ read() [2/2]

template<typename _Tp >

static Ptr<_Tp> cv::Algorithm::read ( const FileNode & fn )

inlinestaticinherited

Reads algorithm from the file node.

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

cv::FileStorage fsRead("example.xml", FileStorage::READ);

Ptr<SVM> svm = Algorithm::read<SVM>(fsRead.root());

In order to make this method work, the derived class must overwrite Algorithm::read(const FileNode& fn) and also have static create() method without parameters (or with all the optional parameters)

◆ 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).

◆ write() [1/2]

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

inlinevirtualinherited

Stores algorithm parameters in a file storage.

Reimplemented in cv::FlannBasedMatcher, cv::DescriptorMatcher, and cv::Feature2D.

References CV_WRAP.

Referenced by cv::Feature2D::write(), and cv::DescriptorMatcher::write().

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◆ write() [2/2]

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

inherited

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

◆ writeFormat()

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

protectedinherited

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

opencv2/imgproc.hpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~LineSegmentDetector()

Member Function Documentation

◆ clear()

◆ compareSegments()

◆ detect()

◆ drawSegments()

◆ empty()

◆ getDefaultName()

◆ load()

◆ loadFromString()

◆ read() [1/2]

◆ read() [2/2]

◆ save()

◆ write() [1/2]

◆ write() [2/2]

◆ writeFormat()