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HARRIS_CORNER_DETECTOR

HARRIS_CORNER_DETECTOR

Name


    HARRIS_CORNER_DETECTOR

Purpose


    This function will find corners in an image. Corners are defined
    in this context as localized areas within the image were small
    shifts in the image in any direction produce a significant
    change in the composition of the neighborhood.

Category


    Image Processing.

Calling Sequence


    Result = $
      HARRIS_CORNER_DETECTOR( image, $
                              sigma, $
                              metric, $
                              OVERLAY=overlay, $
                              DEBUG=debug )

Return Value


    This function will return a 2xN array of coordinates indicating
    corner locations found throughout the provided image.

Inputs


    image
      An array containing the data within which corners are to be
      located.
    sigma
      A scalar defining the standard deviation of the gaussian
      blurring kernel to be used in the smoothing/averaging operation
      used to reduce noise in the intermediate gradient images. This
      quantity is defined in units of pixels. [DEFAULT=1]
    metric
      A flag indicating which response surface metric is to be
      used. The metrics are defined as
          1 - lambda2
          2 - (lambda1 * lambda2) / (lambda1 + lambda2)
          3 - (lambda1 * lambda2) - (lambda1 + lambda2)
          4 - (lambda1 * lambda2) - k*(lambda1 + lambda2)^2 [DEFAULT]

Keyword Parameters


    OVERLAY=overlay
      Indicates a copy of the original image provided is to be returned
      in a 3-band color image format with red pixels indicating where
      the corners found were located.
    DEBUG=debug
      Indicates that debug images/results should be produced at run time
      if set.

Return Value


    This function returns a 2xn array containing the image coordinates of the
    n corner points identified by the FAST detector.

Side Effects


    None

Requires


    FIND_CLUSTER_CENTERS

Reference


    Harris, C. and M.J. Stephens, A combined corner and edge detector,
    Alvey Vision Converence, 1988, pp. 147-152

Side Effects


    None

Modification History


    Written by: Carl Salvaggio
    September, 2008 Original Code
    April, 2012 Added debug keyword todisplay intermediate results

Disclaimer


    This source code is provided "as is" and without warranties as to performance
    or merchantability. The author and/or distributors of this source code may
    have made statements about this source code. Any such statements do not
    constitute warranties and shall not be relied on by the user in deciding
    whether to use this source code.
    This source code is provided without any express or implied warranties
    whatsoever. Because of the diversity of conditions and hardware under which
    this source code may be used, no warranty of fitness for a particular purpose
    is offered. The user is advised to test the source code thoroughly before
    relying on it. The user must assume the entire risk of using the source code.



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