Basic edge detection

For most Computer Vision applications, you process an image but you do not actually need to get all the information from it. For example, sometimes you just need to get the shape information to find an appropriate object. There is a huge topic in the field of image processing called edge detection. Methods related to that topic, search for points where pixel brightness changes dramatically. The extracted information aims to capture changes in the properties of an image. To understand the concept better and to see how the basic edge information can be extracted from an image, we will discuss different edge filters (or operators) starting with the Sobel filter.

The Sobel filter

The Sobel operator or Sobel filter is common and widely used. It helps to detect edges and transitions in images. The Sobel operator uses two kernels during the processing—one for horizontal changes in brightness and another for vertical changes. Its kernel values are focused not on the current pixel...