Feature extraction is an area of image processing which involves using algorithms to detect and isolate various desired portions of a digitized image or video stream.

Contents

1 Low-level 1.1 Curvature 1.2 Image motion 2 Shape Based 2.1 Thresholding 2.2 Template matching 2.3 Hough transform 3 Flexible methods

Low-level

• Edge detection
• Scale invariant feature transform

Curvature

• Edge direction, changing intensity, autocorrelation

Image motion

• Area based, differential approach. Optical flow.

Shape Based

Thresholding

Template matching

Hough transform

• Lines
• Circles/Ellipses
• Arbitrary shapes (Generalized Hough Transform)

Flexible methods

• Deformable, parameterized shapes
• Active contours (snakes)