Feature Extraction and Image Processing for Computer Vision, 4th Edition

4.2. Edge detection

4.2.1. First-order edge detection operators

4.2.1.1. Basic operators

Many approaches to image interpretation are based on edges, since analysis based on edge detection is insensitive to change in the overall illumination level. Edge detection highlights image contrast. Detecting contrast, which is difference in intensity, can emphasise the boundaries of features within an image, since this is where image contrast occurs. This is, naturally, how human vision can perceive the perimeter of an object, since the object is of different intensity to its surroundings. Essentially, the boundary of an object is a step change in the intensity levels. The edge is at the position of the step change. To detect the edge position, ...