Facebook uses the DeepFace tool that uses the deep learning algorithms for the face verification that allows the photo tag suggestions to you when you upload a photo on Facebook. The deep face identifies the faces in the digital images using neural network models. The working of DeepFace is given in below steps:
It first scans the uploaded images. It makes the 3-D model of the image, and then rotate that image into different angles.
After that, it starts matching. To match that image, it uses a neural network model to determine the high-level similarities between other photos of a person. It checks for the different features such as the distance between the eyes, the shape of the nose, eyes color, etc.
Then it does the recursive checking for 68 landmark testing, as each human face consists of 68 specific facial points.
After mapping, it encodes the image and searches for the information of that person.