OpenCV By Example

Segmenting our input image

Now, we will introduce you to the following two techniques used to segment our thresholded image:

• The connected components
• The findContours function

With these two techniques, we will be allowed to extract each region of interest of our image where our target objects appear; in our case, a nut, screw, and ring.

The connected component algorithm

The connected component is a very common algorithm used to segment and identify parts in binary images. A connected component is an iterative algorithm used for the purpose of labeling an image using an 8- or 4-connectivity pixel. Two pixels are connected if they have the same value and are neighbors. In the following figure, each pixel has eight neighbor pixels:

A 4-connectivity