Digital Signal Processing Reference
In-Depth Information
Chapter- 5
Edge Detection
Edge detection
is a fundamental tool in image processing and computer vision,
particularly in the areas of feature detection and feature extraction, which aim at
identifying points in a digital image at which the image brightness changes sharply or,
more formally, has discontinuities.
Motivations
Canny edge detection applied to a photograph
The purpose of detecting sharp changes in image brightness is to capture important
events and changes in properties of the world. It can be shown that under rather general
assumptions for an image formation model, discontinuities in image brightness are likely
to correspond to:
discontinuities in depth,
discontinuities in surface orientation,
changes in material properties and
variations in scene illumination.
In the ideal case, the result of applying an edge detector to an image may lead to a set of
connected curves that indicate the boundaries of objects, the boundaries of surface
markings as well as curves that correspond to discontinuities in surface orientation. Thus,
applying an edge detection algorithm to an image may significantly reduce the amount of
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