Package org.opencv.xfeatures2d

Class 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

    • 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()

      • 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 class Feature2D
        Returns:
        automatically generated

      • finalize

        protected void finalize()
                 throws java.lang.Throwable
        Overrides:
        finalize in class Feature2D
        Throws:
        java.lang.Throwable