Package org.opencv.xfeatures2d
Class SURF
- java.lang.Object
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- org.opencv.core.Algorithm
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- org.opencv.features2d.Feature2D
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- org.opencv.xfeatures2d.SURF
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public class SURF extends 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
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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.
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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
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member int extended
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Constructor Summary
Constructors Modifier Constructor Description protected
SURF(long addr)
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static SURF
__fromPtr__(long addr)
static SURF
create()
64-element descriptors).static SURF
create(double hessianThreshold)
static SURF
create(double hessianThreshold, int nOctaves)
static SURF
create(double hessianThreshold, int nOctaves, int nOctaveLayers)
static SURF
create(double hessianThreshold, int nOctaves, int nOctaveLayers, boolean extended)
static SURF
create(double hessianThreshold, int nOctaves, int nOctaveLayers, boolean extended, boolean upright)
protected void
finalize()
java.lang.String
getDefaultName()
Returns the algorithm string identifier.boolean
getExtended()
double
getHessianThreshold()
int
getNOctaveLayers()
int
getNOctaves()
boolean
getUpright()
void
setExtended(boolean extended)
void
setHessianThreshold(double hessianThreshold)
void
setNOctaveLayers(int nOctaveLayers)
void
setNOctaves(int nOctaves)
void
setUpright(boolean upright)
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Methods inherited from class org.opencv.features2d.Feature2D
compute, compute, defaultNorm, descriptorSize, descriptorType, detect, detect, detect, detect, detectAndCompute, detectAndCompute, empty, read, write
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Methods inherited from class org.opencv.core.Algorithm
clear, getNativeObjAddr, save
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Method Detail
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__fromPtr__
public static SURF __fromPtr__(long addr)
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create
public static SURF create(double hessianThreshold, int nOctaves, int nOctaveLayers, boolean extended, boolean upright)
- 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).- Returns:
- automatically generated
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create
public static SURF create(double hessianThreshold, int nOctaves, int nOctaveLayers, boolean extended)
- 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).- Returns:
- automatically generated
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create
public static SURF create(double hessianThreshold, int nOctaves, int nOctaveLayers)
- 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).- Returns:
- automatically generated
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create
public static SURF create(double hessianThreshold, int nOctaves)
- 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).- Returns:
- automatically generated
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create
public static SURF create(double hessianThreshold)
- Parameters:
hessianThreshold
- Threshold for hessian keypoint detector used in SURF. 64-element descriptors). false - compute orientation).- Returns:
- automatically generated
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create
public static SURF create()
64-element descriptors). false - compute orientation).- Returns:
- automatically generated
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setHessianThreshold
public void setHessianThreshold(double hessianThreshold)
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getHessianThreshold
public double getHessianThreshold()
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setNOctaves
public void setNOctaves(int nOctaves)
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getNOctaves
public int getNOctaves()
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setNOctaveLayers
public void setNOctaveLayers(int nOctaveLayers)
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getNOctaveLayers
public int getNOctaveLayers()
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setExtended
public void setExtended(boolean extended)
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getExtended
public boolean getExtended()
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setUpright
public void setUpright(boolean upright)
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getUpright
public boolean getUpright()
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getDefaultName
public java.lang.String getDefaultName()
Description copied from class:Algorithm
Returns the algorithm string identifier. This string is used as top level xml/yml node tag when the object is saved to a file or string.- Overrides:
getDefaultName
in classFeature2D
- Returns:
- automatically generated
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