NackerHughes 5 days ago

I remember that when it first came out. I get it’s a theoretical or fashion type thing, but the concept seemed flagrantly absurd to me. Block automated facial recognition in a way that in turn makes your face instantly recognisable in any crowd…

3
glenstein 5 days ago

I've heard this as a reaction to the strategy before. "Now you're much more recognizable!" Well, yes and no. You're identifiable in the sense that you're unique among people in a crowd. But that equivocates between two different senses of identify. There's nothing actionable about looking at a person who looks different and saying "well they look different." That doesn't attach to any database or anything.

Meanwhile, positive facial identification attaches to all kinds of legal and intelligence infrastructure. Now, you can be charged with crimes, have a warrant executed against you, can be accused of supporting terrorists if you show up to a protest, etc.

I suppose I don't think the criticism is wrong, but it seems to presume that this is new information not previously understood rather than an intentional calculated risk.

cwmma 5 days ago

Especially at the time it came out, surveillance footage was mainly going to be reviewed by mark I eyeballs, so the inability for computers to notice where a face was is going to be way outweighed by the person being sooo much more recognizable to a human.

If you don't think there is a disadvantage to looking different in a protest, think about the "qanon shaman" from 1/6 him looking different totally made him more of a target to being identified.

glenstein 5 days ago

I'm struggling to understand how this is responsive. Unless those "mark 1 eyeballs" are a positive identification of a specific person, you're repeating my own observations back to me. You can conceivably be noticed in a crowd, but not positively identified.

I don't think "camouflage" fits any definition of what Qanon Shaman was wearing, either in a general sense or in the tactical sense we're talking about here.

cwmma 5 days ago

so first off, if you are noticed in a crowd but not identified, that might single you out to be pulled from the crowd.

Also if you have a distinctive face paint then your image might be shared more, or just noticed more in the images that are shared to give more opportunities for people to recognize you or to remember your face to be recognized latter.

Also having a distinctive face would make it easier to track in different sets of footage especially when the technique was originally demoed in 2011.

glenstein 4 days ago

I understand the mechanism you're tracing, but it feels like there's a category error here. Everything you're saying hinges on the circumstantiality of human reaction and interactions, which is extremely hard to model in a credible way and easy to become colored by subjective biases informed by things like TV and movies. Those channels of recognition and reporting that would lead to positive identification, are nebulous idiosyncratic and depend too much on speculation.

It's not to say it wouldn't ever happen, but there's an order of magnitude difference between that and guaranteed positive identification which is what informs the calculated risk.

genewitch 5 days ago

A hat with infrared LEDs aimed out, such that there was a torus of light around your face. Invisible to humans (generally), only visible to cameras.

It won't "work right" on cameras that have permanent IR filters. Maybe. I haven't tested this in years.

I have a feeling that IR of the correct strength and frequency would be dimly visible to humans, though. Similar to cameras with monochrome night vision via IR LED.

bsenftner 5 days ago

One only needs 1 or two LEDs near their face, but they need to be blinking in short irregular intervals. Cameras have mechanical controls for controlling focus and the amount of light they capture, and that can be attacked with these irregular blinky LEDs that cause the camera to try to adjust to the bright illumination from the LED, but then it is gone before the adjustment is complete, but then it is on again, then off again. The result is a person that never is more than a grey silhouette.

I worked in enterprise FR, on one of the globally leading systems, as the lead developer. That scenario defeats pretty much all FR when from a single camera. It can be mitigated with multiple camera views, which few FR systems are setup for multiple quality views at every key location.

nhecker 5 days ago

Interesting. I bet a candle-flicker LED or two in series would add a nice bit of random (or psuedo-random LSFR?) AM noise to the IR LEDs.

TeMPOraL 5 days ago

That would only maybe work for automated tracking; if someone wants to get the image of your face, they should be able to do it in post, unless the recording quality is shitty - the tiny variations in brightness might contain just enough information to reconstruct the face shape with a little filtering.

(Now I wonder, how narrow-band such IR LED is, and if it could be made to emit a single frequency so sharp, it would create funny diffraction patterns off cameras' surfaces and lens imperfections, clobbering the high-frequency components of the image...)

bsenftner 5 days ago

And it is trained FR algorithm specific, so more than useless in the real world where one does not know what FR system is in use.