Edge detection: Difference between revisions

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The goal of '''edge detection''' is to mark the points in a [[digital image]] at which the [[luminous intensity]] changes sharply. Sharp changes in image properties usually reflect important events and changes in world properties. Edge detection is a research field within [[image processing]] and [[feature extraction]].

Edge detection of an image reduces significantly the amount of data and filters out information that is not very important, preserving the important structural properties of an image. There are many methods for edge detection, but the most can be grouped in two categories, gradientsearch-based and Laplacianzero-crossing based. The gradientsearch-based methodmethods detectsdetect the edgesdges by looking for the maximummaxima and minimumminima in the first derivative of the image, usually the gradient magnitude. The Laplacianzero-crossing methodbased searchesmethods search for zero crossings in the second derivative of the image in order to find edges, usually zero-crossings of the Laplacian or zero-crossings of a non-linear differential expression.

== Edge properties ==