Edge detection
| Feature detection | 
|---|
| Edge detection | 
| Corner detection | 
| Blob detection | 
| Ridge detection | 
| Hough transform | 
| Structure tensor | 
| Affine invariant feature detection | 
| Feature description | 
| Scale space | 
Edge detection includes a variety of mathematical methods that aim at identifying edges, defined as curves in a digital image at which the image brightness changes sharply or, more formally, has discontinuities. The same problem of finding discontinuities in one-dimensional signals is known as step detection and the problem of finding signal discontinuities over time is known as change detection. Edge detection is a fundamental tool in image processing, machine vision and computer vision, particularly in the areas of feature detection and feature extraction.