What Is Facial Recognition? How It Works, Uses and Risks

BusinessSafety and governancePublished By Simon Budziak

Facial recognition is AI that identifies or verifies a person by comparing their face with stored face data. A system finds a face in an image, turns it into a numeric template, and compares that template against one enrolled person or a whole database, then decides whether the similarity is high enough to call a match.

Facial recognition pipeline: detect and align a face, turn it into a faceprint, compare it in 1:1 verification or 1:N identification, then apply a threshold decision

For a business the question is rarely whether the technology works. It is which of two very different jobs you are buying, what happens when it is wrong, and whether the law lets you do it at all.

How does facial recognition actually work?

Every system runs the same short pipeline. A computer vision model detects the face, aligns it so the eyes and mouth sit in standard positions, and a second model converts it into a faceprint: a vector of numbers, an embedding, where similar faces land close together. The system never compares photos. It compares those vectors and returns a similarity score.

The match is a threshold you set, not a fact the model reports. Raise the threshold and the system wrongly accepts fewer strangers but turns away more genuine users. Lower it and the reverse happens. That trade-off is a business decision, and it should be written down before go-live.

1:1 verification vs 1:N identification: what’s the difference?

1:1 verification 1:N identification
Question it answers Is this the person they claim to be? Who is this person?
Compared against One enrolled template A gallery of many people
Typical use Phone unlock, onboarding, payment approval Watchlists, access control, investigations
Person’s role Usually present and consenting Often unaware
Risk profile Lower, the user starts it Higher, error and privacy risk grow with the gallery

Verification and identification are different products with different risk, even when one vendor sells both. Most mid-sized companies need only verification, for example matching a selfie to an ID document during customer onboarding.

Where does the EU restrict facial recognition?

The EU AI Act bans building facial recognition databases through untargeted scraping of images from the internet or CCTV, in Article 5(1)(e), and bans real-time remote biometric identification in publicly accessible spaces for law enforcement except in narrow cases, in Article 5(1)(h); those prohibitions have applied since 2 February 2025 (Regulation (EU) 2024/1689, read 12 November 2026). Remote biometric identification outside those bans is listed as high-risk in Annex III. A face template used to identify someone is special category data under GDPR Article 9, so you need a specific legal ground, usually explicit consent (Regulation (EU) 2016/679, read 12 November 2026). Treat it as a data privacy project first and an AI project second.

What should a buyer ask before deploying it?

Ask four things. Is this 1:1 or 1:N? What false match and false non-match rates did the vendor measure, on which images, and how do they differ across age, sex and skin tone, the AI bias question? Who reviews a match before anyone acts on it? And where are templates stored, for how long, and can a person have theirs deleted? A vendor that cannot answer the error-rate question on your own camera setup has not earned a pilot. Run the pilot on your own images, put a person behind every decision that affects someone’s access or money, and compare it with alternatives such as voice biometrics or a plain document check.

This entry was drafted with AI assistance.

Frequently asked questions

What is the difference between face detection and facial recognition?

Face detection only finds that a face is present and where it is in the image. Facial recognition goes further and compares that face with stored face data to say who it is or whether it matches a claimed identity.

Is facial recognition legal in the EU?

It depends on the use. Building face databases by untargeted scraping is banned, real-time remote identification in public spaces for law enforcement is banned with narrow exceptions, and most other identification uses are high-risk under the EU AI Act, while face templates count as special category data under the GDPR.

How accurate is facial recognition?

The best algorithms are very accurate on good images, but accuracy drops with poor lighting, angle, age gaps and low resolution, and error rates can differ across demographic groups, so test on your own cameras and population before you trust a vendor's figure.

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