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.
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:
-
r radius 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:
-
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
open all close allBasic Examples (1)
Detecting edges in a color image:
Scope (4)
Find edges in a color image:
Specify the scale of edges to detect:
Specify larger scale to detect coarse features:
Edge selection using an explicit global threshold:
Edges of a 3D image:
Options (2)
Method (2)
Shen–Castan edge detection:
By default, all edges are returned, regardless of their straightness:
Filter detected edges with their straightness:
Properties & Relations (1)
EdgeDetect might return edges that are thicker than one pixel:
Use Thinning to get single-pixel-wide edges:
Related Links
- An Elementary Introduction to the Wolfram Language : Images
- An Elementary Introduction to the Wolfram Language : Strings and Text
- An Elementary Introduction to the Wolfram Language : Ways to Apply Functions
- An Elementary Introduction to the Wolfram Language : Applying Functions Repeatedly
- An Elementary Introduction to the Wolfram Language : Creating Websites and Apps
Text
Wolfram Research (2010), EdgeDetect, Wolfram Language function, https://reference.wolfram.com/language/ref/EdgeDetect.html (updated 2014).
CMS
Wolfram Language. 2010. "EdgeDetect." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2014. https://reference.wolfram.com/language/ref/EdgeDetect.html.
APA
Wolfram Language. (2010). EdgeDetect. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/EdgeDetect.html
BibTeX
@misc{reference.wolfram_2025_edgedetect, author="Wolfram Research", title="{EdgeDetect}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/EdgeDetect.html}", note=[Accessed: 25-November-2025]}
BibLaTeX
@online{reference.wolfram_2025_edgedetect, organization={Wolfram Research}, title={EdgeDetect}, year={2014}, url={https://reference.wolfram.com/language/ref/EdgeDetect.html}, note=[Accessed: 25-November-2025]}