EdgeDetect

EdgeDetect[image]

finds edges in image and returns the result as a binary image.

EdgeDetect[image,r]

finds edges at the scale of the specified pixel range r.

EdgeDetect[image,r,t]

uses a threshold t for selecting image edges.

Details and Options

  • Edges of an image are a set of points between image regions and are typically computed by linking high-gradient pixels. In practice, an edge can have an arbitrary shape.
  • EdgeDetect uses gradient methods to find edges and works with arbitrary 2D and 3D images.
  • EdgeDetect[image] is equivalent to EdgeDetect[image,2].
  • The following range specifications r can be used:
  • rradius r in every dimension (default r=2)
    {rrow,rcol}in 2D, range rrow in height, rcol in width
    {rslice,rrow,rcol}in 3D, range rslice in height, rrow in depth, and rcol in width
  • EdgeDetect[image,r,t] uses hysteresis thresholding with a global threshold t. For additional forms of the threshold parameter, see the reference page for MorphologicalBinarize.
  • The following options can be specified:
  • MethodAutomaticedge detection method
    Padding"Fixed"padding method
  • Possible settings for Method include:
  • "Canny"first-order directional Gaussian derivatives (default)
    "ShenCastan"first-order derivatives of exponentials
    "Sobel"binomial generalization of Sobel masks
  • By default, all straight and curved edges are returned. Selection of edges based on their straightness can be done by setting Method->{"method","StraightEdges"->s}. The default behavior is equivalent to "StraightEdges"->0. A setting "StraightEdges"->1 selects only the longest and strongest lines.
  • "StraightEdges" is ignored when used with Image3D objects.

Examples

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Basic Examples  (2)

Detecting edges in a color image:

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Edges of a 3D image:

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Scope  (3)

Options  (2)

Properties & Relations  (1)

See Also

ImageLines  GradientFilter  MorphologicalPerimeter  MorphologicalBinarize  CrossingDetect  CornerFilter  GaussianMatrix  ShenCastanMatrix

Introduced in 2010
(8.0)
| Updated in 2014
(10.0)