4 ms·

> It's much easier to get a detailed image of a person's iris from 100m. Seriously? That sounds insane, wow. I mean, an iris is like 1cm wide, can you really g

by 4ggr0 3y ago

> It's much easier to get a detailed image of a person's iris from 100m. Seriously? That sounds insane, wow. I mean, an iris is like 1cm wide, can you really get a detailed image from 100m away, while the person is walking, looking around, blinking etc.? EDIT: I mean in the context of surveillance, I can imagine that a dedicated photographer could get such a picture with a fancy camera, but we're talking about 24/7 video surveillance.

Tade0 3y ago
> I mean, an iris is like 1cm wide, can you really get a detailed image from 100m away, while the person is walking, looking around, blinking etc.? I assumed there would be an appropriate setup for that. In any case systems collecting iris data en masse from 6m were available a decade ago. Ultimately it's just a photo in near infrared, nothing fancy. The whole reason why this even works is that the iris as a modality has an unrivaled 240+ bits of entropy, so even partial or blurred images yield enough information to identify a person(requiring 60bits at most). On top of that it's an extremely stable feature. Shabrat Gula was famously identified after almost 20 years, despite being a child when her photo was taken.
- 4ggr0 3y ago
  Thanks for the interesting answer, lots of things I want to google now! :D
  - Tade0 3y ago
    If you want to learn more, I recommend a paper by John Daugman - inventor of the encoding system used to store and verify iris data: https://www.robots.ox.ac.uk/~az/lectures/est/iris.pdf https://www.robots.ox.ac.uk/~az/lectures/est/iris.pdf By far the largest database of irises is the one created by India’s Unique Identification Authority, with more than a billion people enrolled: https://www.irisid.com/indian-national-identity-program-tops-one-billion-enrollees-2/ https://www.irisid.com/indian-national-identity-program-tops...

4 ms·

> It's much easier to get a detailed image of a person's iris from 100m. Seriously? That sounds insane, wow. I mean, an iris is like 1cm wide, can you really g

by 4ggr0 3y ago

Tade0 3y ago
> I mean, an iris is like 1cm wide, can you really get a detailed image from 100m away, while the person is walking, looking around, blinking etc.? I assumed there would be an appropriate setup for that. In any case systems collecting iris data en masse from 6m were available a decade ago. Ultimately it's just a photo in near infrared, nothing fancy. The whole reason why this even works is that the iris as a modality has an unrivaled 240+ bits of entropy, so even partial or blurred images yield enough information to identify a person(requiring 60bits at most). On top of that it's an extremely stable feature. Shabrat Gula was famously identified after almost 20 years, despite being a child when her photo was taken.
- 4ggr0 3y ago
  Thanks for the interesting answer, lots of things I want to google now! :D
  - Tade0 3y ago
    If you want to learn more, I recommend a paper by John Daugman - inventor of the encoding system used to store and verify iris data: https://www.robots.ox.ac.uk/~az/lectures/est/iris.pdf https://www.robots.ox.ac.uk/~az/lectures/est/iris.pdf By far the largest database of irises is the one created by India’s Unique Identification Authority, with more than a billion people enrolled: https://www.irisid.com/indian-national-identity-program-tops-one-billion-enrollees-2/ https://www.irisid.com/indian-national-identity-program-tops...