Class for extracting blobs from an image. : More...

#include <features2d.hpp>

Inheritance diagram for cv::SimpleBlobDetector:

Classes
struct	Params

Public Member Functions
virtual CV_WRAP void	setParams (const SimpleBlobDetector::Params &params)=0

virtual CV_WRAP SimpleBlobDetector::Params	getParams () const =0

virtual CV_WRAP String	getDefaultName () const CV_OVERRIDE

virtual CV_WRAP const std::vector< std::vector< cv::Point > > &	getBlobContours () const

Public Member Functions inherited from cv::Feature2D
virtual	~Feature2D ()

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

virtual CV_WRAP void	detect (InputArrayOfArrays images, CV_OUT std::vector< std::vector< KeyPoint > > &keypoints, InputArrayOfArrays masks=noArray())

virtual CV_WRAP void	compute (InputArray image, CV_OUT CV_IN_OUT 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 CV_WRAP void	compute (InputArrayOfArrays images, CV_OUT CV_IN_OUT std::vector< std::vector< KeyPoint > > &keypoints, OutputArrayOfArrays descriptors)

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

virtual CV_WRAP int	descriptorSize () const

virtual CV_WRAP int	descriptorType () const

virtual CV_WRAP int	defaultNorm () const

CV_WRAP void	write (const String &fileName) const

CV_WRAP void	read (const String &fileName)

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

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

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

CV_WRAP void	write (FileStorage &fs, const String &name) const

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

Public Member Functions inherited from cv::Algorithm
	Algorithm ()

virtual	~Algorithm ()

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

CV_WRAP void	write (FileStorage &fs, const String &name) const

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

virtual CV_WRAP void	save (const String &filename) const

Static Public Member Functions
static CV_WRAP Ptr< SimpleBlobDetector >	create (const SimpleBlobDetector::Params &parameters=SimpleBlobDetector::Params())

Static Public Member Functions inherited from cv::Algorithm
template<typename _Tp >
static Ptr< _Tp >	read (const FileNode &fn)
	Reads algorithm from the file node. 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...

Additional Inherited Members
Protected Member Functions inherited from cv::Algorithm
void	writeFormat (FileStorage &fs) const

Detailed Description

Class for extracting blobs from an image. :

The class implements a simple algorithm for extracting blobs from an image:

Convert the source image to binary images by applying thresholding with several thresholds from minThreshold (inclusive) to maxThreshold (exclusive) with distance thresholdStep between neighboring thresholds.
Extract connected components from every binary image by findContours and calculate their centers.
Group centers from several binary images by their coordinates. Close centers form one group that corresponds to one blob, which is controlled by the minDistBetweenBlobs parameter.
From the groups, estimate final centers of blobs and their radiuses and return as locations and sizes of keypoints.

This class performs several filtrations of returned blobs. You should set filterBy* to true/false to turn on/off corresponding filtration. Available filtrations:

By color. This filter compares the intensity of a binary image at the center of a blob to blobColor. If they differ, the blob is filtered out. Use blobColor = 0 to extract dark blobs and blobColor = 255 to extract light blobs.
By area. Extracted blobs have an area between minArea (inclusive) and maxArea (exclusive).
By circularity. Extracted blobs have circularity ( $\frac{4*\pi*Area}{perimeter * perimeter}$ ) between minCircularity (inclusive) and maxCircularity (exclusive).
By ratio of the minimum inertia to maximum inertia. Extracted blobs have this ratio between minInertiaRatio (inclusive) and maxInertiaRatio (exclusive).
By convexity. Extracted blobs have convexity (area / area of blob convex hull) between minConvexity (inclusive) and maxConvexity (exclusive).

Default values of parameters are tuned to extract dark circular blobs.

Member Function Documentation

◆ create()

static CV_WRAP Ptr<SimpleBlobDetector> cv::SimpleBlobDetector::create ( const SimpleBlobDetector::Params & parameters = SimpleBlobDetector::Params() )

static

◆ getBlobContours()

virtual CV_WRAP const std::vector<std::vector<cv::Point> >& cv::SimpleBlobDetector::getBlobContours ( ) const

virtual

◆ getDefaultName()

virtual CV_WRAP String cv::SimpleBlobDetector::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.

◆ getParams()

virtual CV_WRAP SimpleBlobDetector::Params cv::SimpleBlobDetector::getParams ( ) const

pure virtual

◆ setParams()

virtual CV_WRAP void cv::SimpleBlobDetector::setParams ( const SimpleBlobDetector::Params & params )

pure virtual

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

build/release/_deps/opencv-src/include/opencv4/opencv2/features2d.hpp

Classes

Public Member Functions

Static Public Member Functions