After the facial recognition system is connected to the video surveillance system, the recognition software will search for facial information in the camera's field of view. If there is a face in the field of vision, it will detect it within a fraction of a second. It uses multi-scale algorithms to search for facial images at low resolution. An algorithm is a program that provides a set of instructions to complete a specific task. The system only switches to high-resolution search after detecting a shape similar to a head.

Facial recognition software can be classified into a major category of technologies called biometric recognition. Biometric technology uses biometric information to verify identity. The theory behind biometric recognition is that our bodies contain unique features that can be used to distinguish us from others. In addition to facial recognition, biometric identity verification methods also include fingerprint scanning, retinal scanning, and speech recognition.