The following video explains how exactly a computer recognizes a face using OpenCV face detection algorithm. OpenCV is one of the most widely used face detectors. This algorithm performs best for frontal face imagery and excels at computational speed. It's ideal for real-time face detection and is used widely in mobile phone apps, web apps, robotics, and for scientific research.
OpenCV is based on the the Viola-Jones algorithm. This video shows the process used by the Viola Jones algorithm, a cascading set of features that scans across an image at increasing sizes. By understanding how the algorithm detects a face, the process of designing an "anti-face" becomes more intuitive.
An actual tutorial by Jillian Mayer:
Source: https://cvdazzle.com/