Two primary methods of recognizing people by their faces are 2D Facial Recognition:  Algorithms examine a 2D image or video feed of a person's face and compare it to a library of recorded photographs to determine a match. It is often employed in surveillance systems like CCTV cameras because it provides high accuracy given the right conditions. 3D Facial Recognition:  This form of facial recognition uses depth-sensing technology to reconstruct an individual's face in three dimensions before doing feature analysis. Facial recognition in 3D can be more reliable than in 2D since it is less sensitive to environmental factors like illumination and angle.