[−][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
Hardware Acceleration Layer
Modules
| prelude |
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 . |
| Feature2D | |
| FlannBasedMatcher | Flann-based descriptor matcher. |
| KeyPointsFilter | A class filters a vector of keypoints. |
| SimpleBlobDetector | Class for extracting blobs from an image. : |
| SimpleBlobDetector_Params |
Enums
| AKAZE_DescriptorType | |
| AgastFeatureDetector_DetectorType | |
| DescriptorMatcher_MatcherType | |
| DrawMatchesFlags | |
| FastFeatureDetector_DetectorType | |
| KAZE_DiffusivityType | |
| ORB_ScoreType |
Constants
| AgastFeatureDetector_NONMAX_SUPPRESSION | |
| AgastFeatureDetector_THRESHOLD | |
| DrawMatchesFlags_DEFAULT | Output image matrix will be created (Mat::create), i.e. existing memory of output image may be reused. Two source image, matches and single keypoints will be drawn. For each keypoint only the center point will be drawn (without the circle around keypoint with keypoint size and orientation). |
| DrawMatchesFlags_DRAW_OVER_OUTIMG | Output image matrix will not be created (Mat::create). Matches will be drawn on existing content of output image. |
| DrawMatchesFlags_DRAW_RICH_KEYPOINTS | For each keypoint the circle around keypoint with keypoint size and orientation will be drawn. |
| DrawMatchesFlags_NOT_DRAW_SINGLE_POINTS | Single keypoints will not be drawn. |
| FastFeatureDetector_FAST_N | |
| FastFeatureDetector_NONMAX_SUPPRESSION | |
| FastFeatureDetector_THRESHOLD |
Traits
| AKAZE | Class implementing the AKAZE keypoint detector and descriptor extractor, described in ANB13. |
| AgastFeatureDetector | Wrapping class for feature detection using the AGAST method. : |
| BFMatcherTrait | Brute-force descriptor matcher. |
| BOWImgDescriptorExtractorTrait | Class to compute an image descriptor using the bag of visual words. |
| BOWKMeansTrainerTrait | kmeans -based class to train visual vocabulary using the bag of visual words approach. : |
| BOWTrainer | Abstract base class for training the bag of visual words vocabulary from a set of descriptors. |
| BRISKTrait | Class implementing the BRISK keypoint detector and descriptor extractor, described in LCS11 . |
| DescriptorMatcher | Abstract base class for matching keypoint descriptors. |
| FastFeatureDetector | Wrapping class for feature detection using the FAST method. : |
| Feature2DTrait | |
| FlannBasedMatcherTrait | Flann-based descriptor matcher. |
| GFTTDetector | Wrapping class for feature detection using the goodFeaturesToTrack function. : |
| KAZE | Class implementing the KAZE keypoint detector and descriptor extractor, described in ABD12 . |
| KeyPointsFilterTrait | A class filters a vector of keypoints. |
| MSER | Maximally stable extremal region extractor |
| ORB | Class implementing the ORB (oriented BRIEF) keypoint detector and descriptor extractor |
| SimpleBlobDetectorTrait | Class for extracting blobs from an image. : |
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_knn | Draws the found matches of keypoints from two images. |
| evaluate_feature_detector |
|
| get_nearest_point | |
| get_recall |