OpenCV: cv::FlannBasedMatcher Class Reference

| OpenCV 3.4.2 Open Source Computer Vision

Public Member Functions | Static Public Member Functions | Protected Member Functions | Static Protected Member Functions | Protected Attributes | List of all members
cv::FlannBasedMatcher Class Reference
2D Features Framework » Descriptor Matchers

Flann-based descriptor matcher. More...

`#include "features2d.hpp"`

Inheritance diagram for cv::FlannBasedMatcher:

## Public Member Functions
| FlannBasedMatcher (const Ptr< flann::IndexParams > &indexParams=makePtr< flann::KDTreeIndexParams >(), const Ptr< flann::SearchParams > &searchParams=makePtr< flann::SearchParams >())
virtual void | add (InputArrayOfArrays descriptors) CV_OVERRIDE
| Adds descriptors to train a CPU(trainDescCollectionis) or GPU(utrainDescCollectionis) descriptor collection. More...
virtual void | clear () CV_OVERRIDE
| Clears the train descriptor collections. More...
virtual Ptr< DescriptorMatcher > | clone (bool emptyTrainData=false) const CV_OVERRIDE
| Clones the matcher. More...
virtual bool | isMaskSupported () const CV_OVERRIDE
| Returns true if the descriptor matcher supports masking permissible matches. More...
virtual void | read (const FileNode &) CV_OVERRIDE
| Reads algorithm parameters from a file storage. More...
virtual void | train () CV_OVERRIDE
| Trains a descriptor matcher. More...
virtual void | write (FileStorage &) const CV_OVERRIDE
| Stores algorithm parameters in a file storage. More...
Public Member Functions inherited from cv::DescriptorMatcher
virtual | ~DescriptorMatcher ()
virtual bool | empty () const CV_OVERRIDE
| Returns true if there are no train descriptors in the both collections. More...
const std::vector< Mat > & | getTrainDescriptors () const
| Returns a constant link to the train descriptor collection trainDescCollection . More...
void | knnMatch (InputArray queryDescriptors, InputArray trainDescriptors, std::vector< std::vector< DMatch > > &matches, int k, InputArray mask=noArray(), bool compactResult=false) const
| Finds the k best matches for each descriptor from a query set. More...
void | knnMatch (InputArray queryDescriptors, std::vector< std::vector< DMatch > > &matches, int k, InputArrayOfArrays masks=noArray(), bool compactResult=false)
void | match (InputArray queryDescriptors, InputArray trainDescriptors, std::vector< DMatch > &matches, InputArray mask=noArray()) const
| Finds the best match for each descriptor from a query set. More...
void | match (InputArray queryDescriptors, std::vector< DMatch > &matches, InputArrayOfArrays masks=noArray())
void | radiusMatch (InputArray queryDescriptors, InputArray trainDescriptors, std::vector< std::vector< DMatch > > &matches, float maxDistance, InputArray mask=noArray(), bool compactResult=false) const
| For each query descriptor, finds the training descriptors not farther than the specified distance. More...
void | radiusMatch (InputArray queryDescriptors, std::vector< std::vector< DMatch > > &matches, float maxDistance, InputArrayOfArrays masks=noArray(), bool compactResult=false)
void | read (const String &fileName)
void | write (const String &fileName) const
void | write (const Ptr< FileStorage > &fs, const String &name=String()) const
Public Member Functions inherited from cv::Algorithm
| Algorithm ()
virtual | ~Algorithm ()
virtual String | getDefaultName () const
virtual void | save (const String &filename) const
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
static Ptr< FlannBasedMatcher > | create ()
Static Public Member Functions inherited from cv::DescriptorMatcher
static Ptr< DescriptorMatcher > | create (const String &descriptorMatcherType)
| Creates a descriptor matcher of a given type with the default parameters (using default constructor). More...
static Ptr< DescriptorMatcher > | create (int matcherType)
Static Public Member Functions inherited from cv::Algorithm
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
virtual void | knnMatchImpl (InputArray queryDescriptors, std::vector< std::vector< DMatch > > &matches, int k, InputArrayOfArrays masks=noArray(), bool compactResult=false) CV_OVERRIDE
virtual void | radiusMatchImpl (InputArray queryDescriptors, std::vector< std::vector< DMatch > > &matches, float maxDistance, InputArrayOfArrays masks=noArray(), bool compactResult=false) CV_OVERRIDE
Protected Member Functions inherited from cv::DescriptorMatcher
void | checkMasks (InputArrayOfArrays masks, int queryDescriptorsCount) const
Protected Member Functions inherited from cv::Algorithm
void | writeFormat (FileStorage &fs) const

## Static Protected Member Functions
static void | convertToDMatches (const DescriptorCollection &descriptors, const Mat &indices, const Mat &distances, std::vector< std::vector< DMatch > > &matches)
Static Protected Member Functions inherited from cv::DescriptorMatcher
static Mat | clone_op (Mat m)
static bool | isMaskedOut (InputArrayOfArrays masks, int queryIdx)
static bool | isPossibleMatch (InputArray mask, int queryIdx, int trainIdx)

## Protected Attributes
int | addedDescCount
Ptr< flann::Index > | flannIndex
Ptr< flann::IndexParams > | indexParams
DescriptorCollection | mergedDescriptors
Ptr< flann::SearchParams > | searchParams
Protected Attributes inherited from cv::DescriptorMatcher
std::vector< Mat > | trainDescCollection
| Collection of descriptors from train images. More...
std::vector< UMat > | utrainDescCollection

## Additional Inherited Members
Public Types inherited from cv::DescriptorMatcher
enum | { FLANNBASED = 1, BRUTEFORCE = 2, BRUTEFORCE_L1 = 3, BRUTEFORCE_HAMMING = 4, BRUTEFORCE_HAMMINGLUT = 5, BRUTEFORCE_SL2 = 6 }

## Detailed Description

Flann-based descriptor matcher.

This matcher trains cv::flann::Index on a train descriptor collection and calls its nearest search methods to find the best matches. So, this matcher may be faster when matching a large train collection than the brute force matcher. FlannBasedMatcher does not support masking permissible matches of descriptor sets because flann::Index does not support this. :

## Constructor & Destructor Documentation

## ◆ FlannBasedMatcher()

cv::FlannBasedMatcher::FlannBasedMatcher | ( | const Ptr< flann::IndexParams > & | indexParams = `makePtr< flann::KDTreeIndexParams >()`,
|  | const Ptr< flann::SearchParams > & | searchParams = `makePtr< flann::SearchParams >()`
| ) |  |

## Member Function Documentation

## ◆ add()

virtual void cv::FlannBasedMatcher::add | ( | InputArrayOfArrays | descriptors | ) |
| virtual

Adds descriptors to train a CPU(trainDescCollectionis) or GPU(utrainDescCollectionis) descriptor collection.

If the collection is not empty, the new descriptors are added to existing train descriptors.

Parameters

  descriptors | Descriptors to add. Each descriptors[i] is a set of descriptors from the same train image.

Reimplemented from cv::DescriptorMatcher.

## ◆ clear()

virtual void cv::FlannBasedMatcher::clear | ( |  | ) |
| virtual

Clears the train descriptor collections.

Reimplemented from cv::DescriptorMatcher.

## ◆ clone()

virtual Ptr<DescriptorMatcher> cv::FlannBasedMatcher::clone | ( | bool | emptyTrainData = `false` | ) | const
| virtual

Clones the matcher.

Parameters

  emptyTrainData | If emptyTrainData is false, the method creates a deep copy of the object, that is, copies both parameters and train data. If emptyTrainData is true, the method creates an object copy with the current parameters but with empty train data.

Implements cv::DescriptorMatcher.

## ◆ convertToDMatches()

static void cv::FlannBasedMatcher::convertToDMatches | ( | const DescriptorCollection & | descriptors,
|  | const Mat & | indices,
|  | const Mat & | distances,
|  | std::vector< std::vector< DMatch > > & | matches
| ) |  |
| staticprotected

## ◆ create()

static Ptr<FlannBasedMatcher> cv::FlannBasedMatcher::create | ( |  | ) |
| static

## ◆ isMaskSupported()

virtual bool cv::FlannBasedMatcher::isMaskSupported | ( |  | ) | const
| virtual

Returns true if the descriptor matcher supports masking permissible matches.

Implements cv::DescriptorMatcher.

## ◆ knnMatchImpl()

virtual void cv::FlannBasedMatcher::knnMatchImpl | ( | InputArray | queryDescriptors,
|  | std::vector< std::vector< DMatch > > & | matches,
|  | int | k,
|  | InputArrayOfArrays | masks = `noArray()`,
|  | bool | compactResult = `false`
| ) |  |
| protectedvirtual

In fact the matching is implemented only by the following two methods. These methods suppose that the class object has been trained already. Public match methods call these methods after calling train().

Implements cv::DescriptorMatcher.

## ◆ radiusMatchImpl()

virtual void cv::FlannBasedMatcher::radiusMatchImpl | ( | InputArray | queryDescriptors,
|  | std::vector< std::vector< DMatch > > & | matches,
|  | float | maxDistance,
|  | InputArrayOfArrays | masks = `noArray()`,
|  | bool | compactResult = `false`
| ) |  |
| protectedvirtual

Implements cv::DescriptorMatcher.

## ◆ read()

virtual void cv::FlannBasedMatcher::read | ( | const FileNode & | fn | ) |
| virtual

Reads algorithm parameters from a file storage.

Reimplemented from cv::DescriptorMatcher.

## ◆ train()

virtual void cv::FlannBasedMatcher::train | ( |  | ) |
| virtual

Trains a descriptor matcher.

Trains a descriptor matcher (for example, the flann index). In all methods to match, the method train() is run every time before matching. Some descriptor matchers (for example, BruteForceMatcher) have an empty implementation of this method. Other matchers really train their inner structures (for example, FlannBasedMatcher trains flann::Index ).

Reimplemented from cv::DescriptorMatcher.

## ◆ write()

virtual void cv::FlannBasedMatcher::write | ( | FileStorage & | fs | ) | const
| virtual

Stores algorithm parameters in a file storage.

Reimplemented from cv::DescriptorMatcher.

## Member Data Documentation

## ◆ addedDescCount

int cv::FlannBasedMatcher::addedDescCount
| protected

## ◆ flannIndex

Ptr<flann::Index> cv::FlannBasedMatcher::flannIndex
| protected

## ◆ indexParams

Ptr<flann::IndexParams> cv::FlannBasedMatcher::indexParams
| protected

## ◆ mergedDescriptors

DescriptorCollection cv::FlannBasedMatcher::mergedDescriptors
| protected

## ◆ searchParams

Ptr<flann::SearchParams> cv::FlannBasedMatcher::searchParams
| protected

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

- features2d/include/opencv2/features2d.hpp