SURF

Objective-C

@interface SURF : Feature2D

Swift

class SURF : Feature2D

Class for extracting Speeded Up Robust Features from an image CITE: Bay06 .

The algorithm parameters:

member int extended
- 0 means that the basic descriptors (64 elements each) shall be computed
- 1 means that the extended descriptors (128 elements each) shall be computed
member int upright
- 0 means that detector computes orientation of each feature.
- 1 means that the orientation is not computed (which is much, much faster). For example, if you match images from a stereo pair, or do image stitching, the matched features likely have very similar angles, and you can speed up feature extraction by setting upright=1.
member double hessianThreshold Threshold for the keypoint detector. Only features, whose hessian is larger than hessianThreshold are retained by the detector. Therefore, the larger the value, the less keypoints you will get. A good default value could be from 300 to 500, depending from the image contrast.
member int nOctaves The number of a gaussian pyramid octaves that the detector uses. It is set to 4 by default. If you want to get very large features, use the larger value. If you want just small features, decrease it.
member int nOctaveLayers The number of images within each octave of a gaussian pyramid. It is set to 2 by default. @note
- An example using the SURF feature detector can be found at opencv_source_code/samples/cpp/generic_descriptor_match.cpp
  - Another example using the SURF feature detector, extractor and matcher can be found at opencv_source_code/samples/cpp/matcher_simple.cpp

Member of Xfeatures2d

Methods


                    
                    
                    +create:nOctaves:nOctaveLayers:extended:upright:

Declaration

Objective-C

+ (nonnull SURF *)create:(double)hessianThreshold
                nOctaves:(int)nOctaves
           nOctaveLayers:(int)nOctaveLayers
                extended:(BOOL)extended
                 upright:(BOOL)upright;

Swift

class func create(hessianThreshold: Double, nOctaves: Int32, nOctaveLayers: Int32, extended: Bool, upright: Bool) -> SURF

Parameters

`hessianThreshold`	Threshold for hessian keypoint detector used in SURF.
`nOctaves`	Number of pyramid octaves the keypoint detector will use.
`nOctaveLayers`	Number of octave layers within each octave.
`extended`	Extended descriptor flag (true - use extended 128-element descriptors; false - use 64-element descriptors).
`upright`	Up-right or rotated features flag (true - do not compute orientation of features; false - compute orientation).


                    
                    
                    +create:nOctaves:nOctaveLayers:extended:

Declaration

Objective-C

+ (nonnull SURF *)create:(double)hessianThreshold
                nOctaves:(int)nOctaves
           nOctaveLayers:(int)nOctaveLayers
                extended:(BOOL)extended;

Swift

class func create(hessianThreshold: Double, nOctaves: Int32, nOctaveLayers: Int32, extended: Bool) -> SURF

Parameters

`hessianThreshold`	Threshold for hessian keypoint detector used in SURF.
`nOctaves`	Number of pyramid octaves the keypoint detector will use.
`nOctaveLayers`	Number of octave layers within each octave.
`extended`	Extended descriptor flag (true - use extended 128-element descriptors; false - use 64-element descriptors). false - compute orientation).


                    
                    
                    +create:nOctaves:nOctaveLayers:

Declaration

Objective-C

+ (nonnull SURF *)create:(double)hessianThreshold
                nOctaves:(int)nOctaves
           nOctaveLayers:(int)nOctaveLayers;

Swift

class func create(hessianThreshold: Double, nOctaves: Int32, nOctaveLayers: Int32) -> SURF

Parameters

`hessianThreshold`	Threshold for hessian keypoint detector used in SURF.
`nOctaves`	Number of pyramid octaves the keypoint detector will use.
`nOctaveLayers`	Number of octave layers within each octave. 64-element descriptors). false - compute orientation).


                    
                    
                    +create:nOctaves:

Declaration

Objective-C

+ (nonnull SURF *)create:(double)hessianThreshold nOctaves:(int)nOctaves;

Swift

class func create(hessianThreshold: Double, nOctaves: Int32) -> SURF

Parameters

`hessianThreshold`	Threshold for hessian keypoint detector used in SURF.
`nOctaves`	Number of pyramid octaves the keypoint detector will use. 64-element descriptors). false - compute orientation).


                    
                    
                    +create:

Declaration

Objective-C

+ (nonnull SURF *)create:(double)hessianThreshold;

Swift

class func create(hessianThreshold: Double) -> SURF

Parameters


                                hessianThreshold

Threshold for hessian keypoint detector used in SURF. 64-element descriptors). false - compute orientation).

+create
64-element descriptors). false - compute orientation).
Declaration
Objective-C

+ (nonnull SURF *)create;
Swift

class func create() -> SURF


                    
                    
                    -getExtended

Declaration

Objective-C

- (BOOL)getExtended NS_SWIFT_NAME(getExtended());

Swift

func getExtended() -> Bool


                    
                    
                    -getUpright

Declaration

Objective-C

- (BOOL)getUpright NS_SWIFT_NAME(getUpright());

Swift

func getUpright() -> Bool


                    
                    
                    -getHessianThreshold

Declaration

Objective-C

- (double)getHessianThreshold NS_SWIFT_NAME(getHessianThreshold());

Swift

func getHessianThreshold() -> Double


                    
                    
                    -getNOctaveLayers

Declaration

Objective-C

- (int)getNOctaveLayers NS_SWIFT_NAME(getNOctaveLayers());

Swift

func getNOctaveLayers() -> Int32


                    
                    
                    -getNOctaves

Declaration

Objective-C

- (int)getNOctaves NS_SWIFT_NAME(getNOctaves());

Swift

func getNOctaves() -> Int32


                    
                    
                    -setExtended:

Declaration

Objective-C

- (void)setExtended:(BOOL)extended NS_SWIFT_NAME(setExtended(extended:));

Swift

func setExtended(extended: Bool)


                    
                    
                    -setHessianThreshold:

Declaration

Objective-C

- (void)setHessianThreshold:(double)hessianThreshold NS_SWIFT_NAME(setHessianThreshold(hessianThreshold:));

Swift

func setHessianThreshold(hessianThreshold: Double)


                    
                    
                    -setNOctaveLayers:

Declaration

Objective-C

- (void)setNOctaveLayers:(int)nOctaveLayers NS_SWIFT_NAME(setNOctaveLayers(nOctaveLayers:));

Swift

func setNOctaveLayers(nOctaveLayers: Int32)


                    
                    
                    -setNOctaves:

Declaration

Objective-C

- (void)setNOctaves:(int)nOctaves NS_SWIFT_NAME(setNOctaves(nOctaves:));

Swift

func setNOctaves(nOctaves: Int32)


                    
                    
                    -setUpright:

Declaration

Objective-C

- (void)setUpright:(BOOL)upright NS_SWIFT_NAME(setUpright(upright:));

Swift

func setUpright(upright: Bool)