Package org.opencv.xfeatures2d

Class SURF

java.lang.Object

org.opencv.core.Algorithm

org.opencv.features2d.Feature2D

org.opencv.xfeatures2d.SURF

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
• 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

Field Summary

Fields inherited from class org.opencv.core.Algorithm

nativeObj

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SURF(long addr)

Method Summary

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()
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)

Methods inherited from class org.opencv.features2d.Feature2D

compute, compute, defaultNorm, descriptorSize, descriptorType, detect, detect, detect, detect, detectAndCompute, detectAndCompute, empty, getDefaultName, read, write

Methods inherited from class org.opencv.core.Algorithm

clear, getNativeObjAddr, save

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SURF

protected SURF(long addr)

Method Detail

__fromPtr__

public static SURF __fromPtr__(long addr)

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

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

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

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

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

create

public static SURF create()

64-element descriptors). false - compute orientation).

Returns:

automatically generated

setHessianThreshold

public void setHessianThreshold(double hessianThreshold)

getHessianThreshold

public double getHessianThreshold()

setNOctaves

public void setNOctaves(int nOctaves)

getNOctaves

public int getNOctaves()

setNOctaveLayers

public void setNOctaveLayers(int nOctaveLayers)

getNOctaveLayers

public int getNOctaveLayers()

setExtended

public void setExtended(boolean extended)

getExtended

public boolean getExtended()

setUpright

public void setUpright(boolean upright)

getUpright

public boolean getUpright()

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Feature2D

Throws:

Throwable