ImageKeypoints

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

ImageKeypoints
gives the specified property prop for each keypoint.

ImageKeypoints [image] finds keypoints in image and returns their image coordinates as a list of the form .

"Position" image coordinates in the range ,

"PixelPosition" pixel coordinates in the range ,

"Descriptor" SURF keypoint descriptor, given as a unit vector of length 64

"OrientedDescriptor" oriented descriptor

"Orientation" orientation angle, given in radians

"Scale" keypoint scale

"ContrastSign" 1 if the keypoint is lighter than its surrounding, -1 otherwise

The feature descriptors returned by ImageKeypoints are numerically robust against translation, rotation, and scale changes.

(1)

Count the number of interest points in an image:

Out[1]=

(2)

Find keypoints in an image:

Scales, orientations, and contrast signs:

(3)

Visualize the positions of keypoints:

Extract local patches of fixed size around detected keypoints:

Extract patches of size proportional to the scale of keypoints:

Use keypoints to crop an image to keep the main features:

Create thumbnails of uniform size:

(1)

Cluster the keypoints based on their descriptors:

(1)

Visualize the keypoints using their scale, orientation, and contrast:

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