Intuitive image processing — Watershed segmentation
The following content explains the fundamental principle underlying the watershed process. Basic knowledge of general algorithms and computer science principles is assumed. The aim of this article is to provide you with an intuitive understanding of watershed segmentation.
What is a watershed?
A watershed is defined as a region of land that assists in draining water (usually rainwater) into a river or a creek. It is an area of high ground through which water flows into the river or creek.
What is watershed in image processing?
Simply defined, watershed is a transformation on grayscale images. The aim of this technique is to segment the image, typically when two regions-of-interest are close to each other — i.e, their edges touch.
This technique of transformation treats the image as a topographic map, with the intensity of each pixel representing the height. For instance, dark areas can be intuitively considered to be ‘lower’ in height, and can represent troughs. On the other hand, bright areas can be considered to be ‘higher’, acting as hills or as a mountain ridge.
