# How does Global Entry facial recognition work? **URL:** \ **Category:** Factual Questions\ **Created:** [October 26, 2025, 3:36pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303 "2025-10-26T15:36:01Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Tride](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tride/32/13907_2.png) [@Tride](https://boards.straightdope.com/u/Tride)\ **Post date:** [October 26, 2025, 3:36pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/1 "2025-10-26T15:36:01Z")
Just went through GE at LAX. In less than 1 second it has my original picture on the screen to compare to the current shot. Do they coordinate with the airlines so they have a limited data set or is the system really matching the image to the ENTIRE data set in that time? Mind kind of blown. ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [October 26, 2025, 4:40pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/2 "2025-10-26T16:40:33Z")
Most likely they load up your information locally when you buy your tickets to every stop you have. Read that 6 pages of tiny small print disclaimers you agree to when you purchased your ticket and choose your seats. ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [October 26, 2025, 8:17pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/3 "2025-10-26T20:17:47Z")
Global Entry is to enter the US, which even US citizens need a passport for, right? Then I suppose it’s the same as the biometric self-checkout kiosks at European airports: It reads the picture stored on the biometric chip on the passport you’re presenting. ---
**Author:** ![Tride](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tride/32/13907_2.png) [@Tride](https://boards.straightdope.com/u/Tride)\ **Post date:** [October 26, 2025, 8:36pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/4 "2025-10-26T20:36:41Z")
Nope–no passport or boarding pass or ID of any sort presented. Stand in front of the camera and almost instantly your current pic and original pic are side by side… ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [October 26, 2025, 8:56pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/5 "2025-10-26T20:56:45Z")
This seems obvious but isn’t the Global Entry kiosk online and connected to a central database? ---
**Author:** ![Tride](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tride/32/13907_2.png) [@Tride](https://boards.straightdope.com/u/Tride)\ **Post date:** [October 26, 2025, 8:58pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/6 "2025-10-26T20:58:27Z")
Of course, but to be able to parse facial recognition for the (WAG) 20 million folks in the GE database in less than a second is crazy to me. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [October 26, 2025, 9:03pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/7 "2025-10-26T21:03:14Z")
Prior to departure, the airline provides a list of passengers to Customs and Border Protection. From [here](https://www.cbp.gov/travel/clearing-cbp/passenger-name-record) > U.S. law requires air carriers operating flights to, from, or through the United States to provide the Department of Homeland Security (DHS), U.S. Customs and Border Protection (CBP), with certain passenger reservation information, called Passenger Name Record (PNR) data. This information is transmitted to CBP prior to departure and used primarily for purposes of preventing, detecting, investigating, and prosecuting terrorist offenses and related crimes and certain other crimes that are transnational in nature. So they _could_ be reducing the number of records to be compared to those in that list for every international flight at that airport. ---
**Author:** ![Tride](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tride/32/13907_2.png) [@Tride](https://boards.straightdope.com/u/Tride)\ **Post date:** [October 26, 2025, 9:11pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/8 "2025-10-26T21:11:54Z")
That makes sense and is what I actually expected. Less spooky! ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [October 26, 2025, 9:14pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/9 "2025-10-26T21:14:29Z")
Facial recognition systems don’t recognize faces. Generally speaking, they pick out points on the face and measure the distances between them and other points. That’s converted into a “facecode” of numbers. Presumably, like fingerprints, facecodes will produce a unique number. Checking numbers in a database is fast and easy these days. Most of the time needed for the process went into reading your face in the first place, which you didn’t account for. It’s like a magic trick that way. And it’s gotten much faster and better in the same way that AI has. Here’s a good explanation. > **[How does facial recognition work, how is it used, and is it safe?](https://us.norton.com/blog/iot/how-facial-recognition-software-works)** > > From your phone to public cameras, facial recognition is everywhere. Understand how it works and how to keep your data safer. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 26, 2025, 9:58pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/10 "2025-10-26T21:58:50Z")
I’m not sure that “facecodes” are completely unique, though (at least, not if there’s enough tolerance in the system to assign the same code to the same face under varying conditions). You probably couldn’t pick out one person out of 9 billion just from their face. I’d expect that this system would work by, first, making sure that your face IS a match for one of the faces in the short list of people who’s supposed to be on the flight, and second, that it is NOT a match for any of the faces on a not-quite-as-short list of known criminals who shouldn’t be allowed to fly. Match both or neither, and they probably take you aside for further questioning/identifying/processing. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [October 26, 2025, 10:10pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/11 "2025-10-26T22:10:33Z")
Work on this question has been done since the early days. Theoretically, at least, even eight points will provide a unique answer. > **[Are human faces unique? A metric approach to finding single individuals...](https://www.sciencedirect.com/science/article/abs/pii/S0379073815003758)** > > In the forensic sciences it is inferred that human individuals are unique and thus can be reliably identified. The concept of individual uniqueness is… Modern systems use many more than eight, up to around twenty. Whether the proper precision can be obtained and measured in limited time is a different, engineering, question. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 26, 2025, 10:26pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/12 "2025-10-26T22:26:17Z")
That’s more complicated than putting a single numerical code in the database and finding a single numerical code for the face you’re looking at and seeing if they match, though. What they’re talking about there is putting a code in the database and getting a code from the face you’re looking at, and then seeing if those two codes are close enough. Which is a more difficult database problem. In fact, I’m pretty sure it would be completely impossible to create a system that required exact code matches (though you might use a system like that as a first pass, to narrow down the search space). ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [October 26, 2025, 11:06pm UTC](https://boards.straightdope.com/t/how-does-global-entry-facial-recognition-work/1024303/13 "2025-10-26T23:06:05Z")
Yes, I believe that systems use similarity matches IRL. The gap between similar and identical has been narrowing, however.