Segmenting our input image
Now, we will introduce you to the following two techniques used to segment our thresholded image:
The connected components
The
findContoursfunction
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 means that only the 2, 4, 5, and 7 neighbors can be connected to the center if they have the same value. In the case of 8-connectivity, 1, 2, 3, 4, 5, 6, 7, and 8 can be connected if they have the same value.
In the following example, we can see the difference...
