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Comment by codedokode | Hacker News Reader

I am not sure if passport photo is good enough for this. The mimimum requirement for face recognition is about 50 pixels between the eyes, and for reliable recognition it probably should be more. So the photo must come from somewhere else. For example, it could be taken when she passed the gates previous time.

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In Europe there’s automated passport control gates with face recognition in several airports. These are based on the photo stored on passport. Not sure how automatic these are - would be of course possible to have a human there looking at the photos.

According to quick search there’s no specific resolution requirement for the image in biometric passport, but size should be min 12kB to have recognizable image.

https://readid.com/blog/face-images-in-ePassports

There is a human looking at the photos. When you take the Eurostar you can see them sitting in a booth after the gates. If you look into the booth as you pass, you'll see a grid of photos on screen. I'm assuming they're overseeing it all rather than checking everything manually.

I noticed that these gates were quite slow ID'ing me the first couple of times I went through them but now I hardly have the time to see my face flash on the screen before the gates open. Maybe there's a human check on initial passes. Either that or their code has gotten way better or they store data that helps matching after a few uses.

I've had a beard and not, a shaved head and not, and mine feel slower than others. Tough to verify with an N=1, but that wouldn't really surprise me if they were.

I'm also flying to Kenya and other E. African countries so it wouldn't be surprising if they flagged me.

I always assumed they are storing every photo to help recognition because it definitely seems to get better the more you use it. You're right there is a human there though monitoring it, I assume they only step in when the system cant identify you.

The human is only a second-level control in case the confidence level is too low, or the system can't match the face with the passport photo. Also, the face is matched against the photo stored in the electronic passport, not against a central database. With respect to resolution etc., there are specifications in place about the quality of the passport photo. If your photo doesn't meet them, you will be asked to submit another photo for your passport application.

I'm not sure what the resolution is (I tried it out a few years back), but you can actually pull your digital passport photo out of your passport using NFC. There's an Android app for it.

Not to mention some portion of photos would have to be out-of-date or otherwise unusable.

My guess is the app probably just approved anyone or nearly anyone. It's unlikely someone without a boarding pass would try to get on and it's likely that anyone with a boarding pass who got disapproved would be pissed.

Or who knows, maybe homeland security did a mechanical Turk and had someone at the other end looking at faces and checking off names.

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