[−][src]Module opencv::features2d

2D Features Framework

Feature Detection and Description

Descriptor Matchers

Matchers of keypoint descriptors in OpenCV have wrappers with a common interface that enables you to easily switch between different algorithms solving the same problem. This section is devoted to matching descriptors that are represented as vectors in a multidimensional space. All objects that implement vector descriptor matchers inherit the DescriptorMatcher interface.

Note:

An example explaining keypoint matching can be found at opencv_source_code/samples/cpp/descriptor_extractor_matcher.cpp
An example on descriptor matching evaluation can be found at opencv_source_code/samples/cpp/detector_descriptor_matcher_evaluation.cpp
An example on one to many image matching can be found at opencv_source_code/samples/cpp/matching_to_many_images.cpp

Drawing Function of Keypoints and Matches

Object Categorization

This section describes approaches based on local 2D features and used to categorize objects.

Note:

A complete Bag-Of-Words sample can be found at opencv_source_code/samples/cpp/bagofwords_classification.cpp
(Python) An example using the features2D framework to perform object categorization can be found at opencv_source_code/samples/python/find_obj.py

Structs

BFMatcher	Brute-force descriptor matcher.
BOWImgDescriptorExtractor	Class to compute an image descriptor using the bag of visual words.
BOWKMeansTrainer	kmeans -based class to train visual vocabulary using the bag of visual words approach. :
BRISK	Class implementing the BRISK keypoint detector and descriptor extractor, described in LCS11 .
FlannBasedMatcher	Flann-based descriptor matcher.
KeyPointsFilter	A class filters a vector of keypoints.
SimpleBlobDetector	Class for extracting blobs from an image. :
SimpleBlobDetector_Params

Constants

AKAZE_DESCRIPTOR_KAZE
AKAZE_DESCRIPTOR_KAZE_UPRIGHT
AKAZE_DESCRIPTOR_MLDB
AKAZE_DESCRIPTOR_MLDB_UPRIGHT
AgastFeatureDetector_AGAST_5_8
AgastFeatureDetector_AGAST_7_12d
AgastFeatureDetector_AGAST_7_12s
AgastFeatureDetector_OAST_9_16
CV_HAL_TYPE_5_8
CV_HAL_TYPE_7_12
CV_HAL_TYPE_9_16
DescriptorMatcher_BRUTEFORCE
DescriptorMatcher_BRUTEFORCE_HAMMING
DescriptorMatcher_BRUTEFORCE_HAMMINGLUT
DescriptorMatcher_BRUTEFORCE_L1
DescriptorMatcher_BRUTEFORCE_SL2
DescriptorMatcher_FLANNBASED
DrawMatchesFlags_DEFAULT	Output image matrix will be created (Mat::create),
DrawMatchesFlags_DRAW_OVER_OUTIMG	Output image matrix will not be created (Mat::create).
DrawMatchesFlags_DRAW_RICH_KEYPOINTS	For each keypoint the circle around keypoint with keypoint size and
DrawMatchesFlags_NOT_DRAW_SINGLE_POINTS	Single keypoints will not be drawn.
FastFeatureDetector_FAST_N
FastFeatureDetector_NONMAX_SUPPRESSION
FastFeatureDetector_THRESHOLD
FastFeatureDetector_TYPE_5_8
FastFeatureDetector_TYPE_7_12
FastFeatureDetector_TYPE_9_16
KAZE_DIFF_CHARBONNIER
KAZE_DIFF_PM_G1
KAZE_DIFF_PM_G2
KAZE_DIFF_WEICKERT
ORB_FAST_SCORE
ORB_HARRIS_SCORE
ORB_kBytes

Traits

AKAZE	Class implementing the AKAZE keypoint detector and descriptor extractor, described in ANB13.
AgastFeatureDetector	Wrapping class for feature detection using the AGAST method. :
BOWTrainer	Abstract base class for training the bag of visual words vocabulary from a set of descriptors.
DescriptorMatcher	Abstract base class for matching keypoint descriptors.
FastFeatureDetector	Wrapping class for feature detection using the FAST method. :
Feature2D	Abstract base class for 2D image feature detectors and descriptor extractors
GFTTDetector	Wrapping class for feature detection using the goodFeaturesToTrack function. :
KAZE	Class implementing the KAZE keypoint detector and descriptor extractor, described in ABD12 .
MSER	Maximally stable extremal region extractor
ORB	Class implementing the ORB (oriented BRIEF) keypoint detector and descriptor extractor

Functions

AGAST	Detects corners using the AGAST algorithm
AGAST_with_type	Detects corners using the AGAST algorithm
FAST	Detects corners using the FAST algorithm
FAST_with_type	Detects corners using the FAST algorithm
compute_recall_precision_curve
draw_keypoints	Draws keypoints.
draw_matches	Draws the found matches of keypoints from two images.
draw_matches_vec	Draws the found matches of keypoints from two images.
evaluate_feature_detector	Functions to evaluate the feature detectors and [generic] descriptor extractors *
get_nearest_point
get_recall