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 Details

    • SURF

      protected SURF(long addr)
  • Method Details

    • __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 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 Throwable
      Overrides:
      finalize in class Feature2D
      Throws:
      Throwable