ImageKeypoints

ImageKeypoints[image]
finds key features in image and returns their coordinates.

ImageKeypoints[image,prop]
gives the specified property prop for each keypoint.

Details and OptionsDetails and Options

  • ImageKeypoints[image] finds keypoints in image with image dimensions and returns their image coordinates as a list of the form .
  • The following properties can be specified:
  • "Position"image coordinates in the range ,
    "PixelPosition"pixel coordinates in the range ,
    "Scale"keypoint scale
    "Orientation"orientation angle, given in radians
    "Strength"blob response, given as a positive number
    "ContrastSign" if the keypoint is lighter than its surroundings, otherwise
    "Descriptor"SURF keypoint descriptor, given as a unit vector of length 64
    "OrientedDescriptor"oriented descriptor
  • ImageKeypoints sorts the results based on the property of the keypoints.
  • ImageKeypoints[image,{prop1,prop2,}] returns multiple properties.
  • The feature descriptors returned by ImageKeypoints are numerically robust against translation, rotation, and scale changes.
  • The following options can be specified:
  • KeypointStrength0minimum strength of the keypoints
    MaxFeaturesAllmaximum number of keypoints
  • With a setting MaxFeatures->n, at most n keypoints with largest are returned.
  • ImageKeypoints uses the SURF keypoint detection method.
Introduced in 2010
(8.0)
| Updated in 2012
(9.0)