2. Face preprocessing: It is the process of adjusting the face image to look more
clear and similar to other faces (a small grayscale face in the top-center of the
following screenshot).
3. Collect and learn faces: It is the process of saving many preprocessed faces
(for each person that should be recognized), and then learning how to
recognize them.
4. Face recognition: It is the process that checks which of the collected people
are most similar to the face in the camera (a small rectangle on the top-right
of the following screenshot).