20070306-Connected component labeling – Part 1

原文：http://blogs.mathworks.com/steve/2007/03/06/connected-component-labeling-part-1/

bwlabel implements an operation known as connected component labeling, or sometimes blob labeling. So, what is a connected component, and what does it mean to label it?

Let's start by looking at a simple binary image:

bw = imread('http://blogs.mathworks.com/images/steve/119/binary.png');
imshow(bw)

In subsequent posts I'll write about several methods you might use to find connected components, including the particular methods used by bwlabel and its multidimensional cousin bwlabeln. I'll also explain how the exact definition of a pixel's neighborhood affects the results.