Edge Detection

Edge detection is an important step in segmentation of the image and leads to object recognition. An edge is a line of interaction of two disjoint surfaces. That is, an edge is a set of connected pixels that forms a boundary between two disjoint regions of an image. Edges are detected using operators based on the first and second derivatives of the image. A high value or a zero crossing of the response of the operators indicate an edge pixel. Derivatives are approximated by differences in digital images. Commonly used edge operators are presented with examples.