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.
  • ImageKeypoints accepts a MaxFeatures option. The default setting is MaxFeatures->All. With a setting MaxFeatures->n, at most n keypoints with largest are returned.
  • ImageKeypoints accepts a option. Using "KeypointStrength"->s, only keypoints whose strength is larger than s are returned.
  • ImageKeypoints uses the SURF keypoint detection method.
New in 8 | Last modified in 9
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