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Feature Detection and Description

Feature Detection and Description
[2D Features Framework]

Data Structures

class  BRISK
 Class implementing the BRISK keypoint detector and descriptor extractor, described in LCS11 . More...
class  ORB
 Class implementing the ORB (*oriented BRIEF*) keypoint detector and descriptor extractor. More...
class  MSER
 Maximally stable extremal region extractor. More...
class  FastFeatureDetector
 Wrapping class for feature detection using the FAST method. More...
class  AgastFeatureDetector
 Wrapping class for feature detection using the AGAST method. More...
class  GFTTDetector
 Wrapping class for feature detection using the goodFeaturesToTrack function. More...
class  SimpleBlobDetector
 Class for extracting blobs from an image. More...
class  KAZE
 Class implementing the KAZE keypoint detector and descriptor extractor, described in ABD12 . More...
class  AKAZE
 Class implementing the AKAZE keypoint detector and descriptor extractor, described in ANB13 . More...

Functions

CV_EXPORTS void FAST (InputArray image, CV_OUT std::vector< KeyPoint > &keypoints, int threshold, bool nonmaxSuppression=true)
CV_EXPORTS void FAST (InputArray image, CV_OUT std::vector< KeyPoint > &keypoints, int threshold, bool nonmaxSuppression, int type)
 Detects corners using the FAST algorithm.
CV_EXPORTS void AGAST (InputArray image, CV_OUT std::vector< KeyPoint > &keypoints, int threshold, bool nonmaxSuppression=true)
CV_EXPORTS void AGAST (InputArray image, CV_OUT std::vector< KeyPoint > &keypoints, int threshold, bool nonmaxSuppression, int type)
 Detects corners using the AGAST algorithm.

Function Documentation

CV_EXPORTS void cv::AGAST ( InputArray  image,
CV_OUT std::vector< KeyPoint > &  keypoints,
int  threshold,
bool  nonmaxSuppression = true 
)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

CV_EXPORTS void cv::AGAST ( InputArray  image,
CV_OUT std::vector< KeyPoint > &  keypoints,
int  threshold,
bool  nonmaxSuppression,
int  type 
)

Detects corners using the AGAST algorithm.

Parameters:
imagegrayscale image where keypoints (corners) are detected.
keypointskeypoints detected on the image.
thresholdthreshold on difference between intensity of the central pixel and pixels of a circle around this pixel.
nonmaxSuppressionif true, non-maximum suppression is applied to detected corners (keypoints).
typeone of the four neighborhoods as defined in the paper: AgastFeatureDetector::AGAST_5_8, AgastFeatureDetector::AGAST_7_12d, AgastFeatureDetector::AGAST_7_12s, AgastFeatureDetector::OAST_9_16

For non-Intel platforms, there is a tree optimised variant of AGAST with same numerical results. The 32-bit binary tree tables were generated automatically from original code using perl script. The perl script and examples of tree generation are placed in features2d/doc folder. Detects corners using the AGAST algorithm by mair2010_agast .

CV_EXPORTS void cv::FAST ( InputArray  image,
CV_OUT std::vector< KeyPoint > &  keypoints,
int  threshold,
bool  nonmaxSuppression = true 
)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

CV_EXPORTS void cv::FAST ( InputArray  image,
CV_OUT std::vector< KeyPoint > &  keypoints,
int  threshold,
bool  nonmaxSuppression,
int  type 
)

Detects corners using the FAST algorithm.

Parameters:
imagegrayscale image where keypoints (corners) are detected.
keypointskeypoints detected on the image.
thresholdthreshold on difference between intensity of the central pixel and pixels of a circle around this pixel.
nonmaxSuppressionif true, non-maximum suppression is applied to detected corners (keypoints).
typeone of the three neighborhoods as defined in the paper: FastFeatureDetector::TYPE_9_16, FastFeatureDetector::TYPE_7_12, FastFeatureDetector::TYPE_5_8

Detects corners using the FAST algorithm by Rosten06 .

Note:
In Python API, types are given as cv2.FAST_FEATURE_DETECTOR_TYPE_5_8, cv2.FAST_FEATURE_DETECTOR_TYPE_7_12 and cv2.FAST_FEATURE_DETECTOR_TYPE_9_16. For corner detection, use cv2.FAST.detect() method.