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This is a base class for all more or less complex algorithms in OpenCV. More...

#include <opencv2/core.hpp>

Inheritance diagram for cv::Algorithm:
cv::AlignExposures cv::BackgroundSubtractor cv::BaseCascadeClassifier cv::CLAHE cv::CalibrateCRF cv::DenseOpticalFlow cv::DescriptorMatcher cv::Feature2D cv::GeneralizedHough cv::HistogramCostExtractor cv::LMSolver cv::LineSegmentDetector cv::MergeExposures cv::MinProblemSolver cv::ShapeDistanceExtractor cv::ShapeTransformer cv::SparseOpticalFlow cv::StereoMatcher cv::Tonemap cv::aruco::ArucoDetector cv::aruco::CharucoDetector cv::bgsegm::SyntheticSequenceGenerator cv::bioinspired::Retina cv::bioinspired::RetinaFastToneMapping cv::bioinspired::TransientAreasSegmentationModule cv::ccalib::CustomPattern cv::cuda::CannyEdgeDetector cv::cuda::CascadeClassifier cv::cuda::Convolution cv::cuda::CornernessCriteria cv::cuda::CornersDetector cv::cuda::DFT cv::cuda::DenseOpticalFlow cv::cuda::DescriptorMatcher cv::cuda::DisparityBilateralFilter cv::cuda::Filter cv::cuda::HOG cv::cuda::HoughCirclesDetector cv::cuda::HoughLinesDetector cv::cuda::HoughSegmentDetector cv::cuda::ImagePyramid cv::cuda::LookUpTable cv::cuda::NvidiaHWOpticalFlow cv::cuda::SparseOpticalFlow cv::cuda::TemplateMatching cv::dnn::Layer cv::face::BIF cv::face::FaceRecognizer cv::face::Facemark cv::face::MACE cv::freetype::FreeType2 cv::hfs::HfsSegment cv::img_hash::ImgHashBase cv::legacy::MultiTracker cv::legacy::Tracker cv::line_descriptor::BinaryDescriptor cv::line_descriptor::BinaryDescriptorMatcher cv::line_descriptor::LSDDetector cv::mcc::CCheckerDetector cv::ml::SVM::Kernel cv::ml::StatModel cv::optflow::GPCForest< T > cv::optflow::GPCTree cv::phase_unwrapping::PhaseUnwrapping cv::plot::Plot2d cv::quality::QualityBase cv::rapid::Tracker cv::rgbd::DepthCleaner cv::rgbd::Odometry cv::rgbd::RgbdNormals cv::rgbd::RgbdPlane cv::saliency::Saliency cv::stereo::StereoMatcher cv::structured_light::StructuredLightPattern cv::superres::DenseOpticalFlowExt cv::superres::SuperResolution cv::text::ERFilter cv::xfeatures2d::PCTSignatures cv::xfeatures2d::PCTSignaturesSQFD cv::ximgproc::AdaptiveManifoldFilter cv::ximgproc::ContourFitting cv::ximgproc::DTFilter cv::ximgproc::DisparityFilter cv::ximgproc::EdgeBoxes cv::ximgproc::EdgeDrawing cv::ximgproc::FastBilateralSolverFilter cv::ximgproc::FastGlobalSmootherFilter cv::ximgproc::FastLineDetector cv::ximgproc::GuidedFilter cv::ximgproc::RFFeatureGetter cv::ximgproc::RidgeDetectionFilter cv::ximgproc::ScanSegment cv::ximgproc::SparseMatchInterpolator cv::ximgproc::StructuredEdgeDetection cv::ximgproc::SuperpixelLSC cv::ximgproc::SuperpixelSEEDS cv::ximgproc::SuperpixelSLIC cv::ximgproc::segmentation::GraphSegmentation cv::ximgproc::segmentation::SelectiveSearchSegmentation cv::ximgproc::segmentation::SelectiveSearchSegmentationStrategy cv::xphoto::WhiteBalancer

Public Member Functions

 Algorithm ()
 
virtual ~Algorithm ()
 
virtual void clear ()
 Clears the algorithm state.
 
virtual bool empty () const
 Returns true if the Algorithm is empty (e.g. in the very beginning or after unsuccessful read.
 
virtual String getDefaultName () const
 
virtual void read (const FileNode &fn)
 Reads algorithm parameters from a file storage.
 
virtual void save (const String &filename) const
 
void write (const Ptr< FileStorage > &fs, const String &name=String()) const
 
virtual void write (FileStorage &fs) const
 Stores algorithm parameters in a file storage.
 
void write (FileStorage &fs, const String &name) const
 

Static Public Member Functions

template<typename _Tp >
static Ptr< _Tpload (const String &filename, const String &objname=String())
 Loads algorithm from the file.
 
template<typename _Tp >
static Ptr< _TploadFromString (const String &strModel, const String &objname=String())
 Loads algorithm from a String.
 
template<typename _Tp >
static Ptr< _Tpread (const FileNode &fn)
 Reads algorithm from the file node.
 

Protected Member Functions

void writeFormat (FileStorage &fs) const
 

Detailed Description

This is a base class for all more or less complex algorithms in OpenCV.

especially for classes of algorithms, for which there can be multiple implementations. The examples are stereo correspondence (for which there are algorithms like block matching, semi-global block matching, graph-cut etc.), background subtraction (which can be done using mixture-of-gaussians models, codebook-based algorithm etc.), optical flow (block matching, Lucas-Kanade, Horn-Schunck etc.).

Here is example of SimpleBlobDetector use in your application via Algorithm interface:

FileStorage fs_read("SimpleBlobDetector_params.xml", FileStorage::READ);
if (fs_read.isOpened()) // if we have file with parameters, read them
{
sbd->read(fs_read.root());
fs_read.release();
}
else // else modify the parameters and store them; user can later edit the file to use different parameters
{
fs_read.release();
FileStorage fs_write("SimpleBlobDetector_params.xml", FileStorage::WRITE);
sbd->write(fs_write);
fs_write.release();
}
Mat result, image = imread("../data/detect_blob.png", IMREAD_COLOR);
vector<KeyPoint> keypoints;
sbd->detect(image, keypoints, Mat());
drawKeypoints(image, keypoints, result);
for (vector<KeyPoint>::iterator k = keypoints.begin(); k != keypoints.end(); ++k)
circle(result, k->pt, (int)k->size, Scalar(0, 0, 255), 2);
imshow("result", result);
waitKey(0);
XML/YAML/JSON file storage class that encapsulates all the information necessary for writing or readi...
Definition: persistence.hpp:304
@ WRITE
value, open the file for writing
Definition: persistence.hpp:310
@ READ
value, open the file for reading
Definition: persistence.hpp:309
static Ptr< SimpleBlobDetector > create(const SimpleBlobDetector::Params &parameters=SimpleBlobDetector::Params())
Scalar_< double > Scalar
Definition: types.hpp:702
std::shared_ptr< _Tp > Ptr
Definition: cvstd_wrapper.hpp:23
void drawKeypoints(InputArray image, const std::vector< KeyPoint > &keypoints, InputOutputArray outImage, const Scalar &color=Scalar::all(-1), DrawMatchesFlags flags=DrawMatchesFlags::DEFAULT)
Draws keypoints.
void imshow(const String &winname, InputArray mat)
Displays an image in the specified window.
int waitKey(int delay=0)
Waits for a pressed key.
@ IMREAD_COLOR
If set, always convert image to the 3 channel BGR color image.
Definition: imgcodecs.hpp:72
CV_EXPORTS_W Mat imread(const String &filename, int flags=IMREAD_COLOR)
Loads an image from a file.
void circle(InputOutputArray img, Point center, int radius, const Scalar &color, int thickness=1, int lineType=LINE_8, int shift=0)
Draws a circle.

Constructor & Destructor Documentation

◆ Algorithm()

cv::Algorithm::Algorithm ( )

◆ ~Algorithm()

virtual cv::Algorithm::~Algorithm ( )
virtual

Member Function Documentation

◆ clear()

◆ empty()

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

◆ getDefaultName()

◆ load()

template<typename _Tp >
static Ptr< _Tp > cv::Algorithm::load ( const String filename,
const String objname = String() 
)
inlinestatic

Loads algorithm from the file.

Parameters
filenameName of the file to read.
objnameThe 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).

◆ loadFromString()

template<typename _Tp >
static Ptr< _Tp > cv::Algorithm::loadFromString ( const String strModel,
const String objname = String() 
)
inlinestatic

Loads algorithm from a String.

Parameters
strModelThe string variable containing the model you want to load.
objnameThe 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);

◆ read() [1/2]

◆ read() [2/2]

template<typename _Tp >
static Ptr< _Tp > cv::Algorithm::read ( const FileNode fn)
inlinestatic

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
virtual

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

◆ write() [1/3]

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

◆ write() [2/3]

◆ write() [3/3]

void cv::Algorithm::write ( FileStorage fs,
const String name 
) const

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
protected

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