iphone face recognition photos
How do I get iPhone to recognize faces in photos? How do you add faces to photos?

Facial recognition and biometric scanning systems also use computer vision technology to identify individuals for security purposes. The most common example of computer vision in facial recognition is for securing smartphones. More advanced uses of facial recognition and biometrics include in residential or business security systems that use unique physiological features of individuals to verify their identity. Deep learning algorithms can identify the unique patterns in a person’s fingerprints and use it to control access to high-security areas such as high-confidentiality workplaces, such as nuclear powerplants, research labs, and bank vaults.

The Photos app recognises the faces of people in your photos and groups them together. You can give names to faces, mark your favourites 
Your iPhone's Photos app will make a People album for faces it