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Shadow Analysis Could Spot Terrorists
Hugh Pickens writes "An engineer at Jet Propulsion Labs says it should be possible to identify people from the way they walk — a technique called gait analysis, whose power lies in the fact that a person's walking style is very hard to disguise. Adrian Stoica has written software that recognizes human movement in aerial and satellite video footage by isolating moving shadows and using data on the time of day and the camera angle to correct shadows that are elongated or foreshortened. In tests on footage shot from the sixth floor of a building, Stoica says his software was indeed able to extract useful gait data. Extending the idea to satellites could prove trickier, though. Space imaging expert Bhupendra Jasani at King's College London says geostationary satellites simply don't have the resolution to provide useful detail. 'I find it hard to believe they could apply this technique from space,' says Jasani." Comments on the article speculate on the maximum resolution possible from KH-11 and KH-12 spy satellites.
Go ahead, develop more technology, there's always around it.
An engineer at Jet Propulsion Labs says it should be possible to identify people from the way they walk -- a technique called gait analysis, whose power lies in the fact that a person's walking style is very hard to disguise.
I knew it! The Ministry of Silly Walks is really just a subdivision of MI6!
Defeated by a simple 2 inch lift in one shoe.
Obviously, but this isn't exactly rocket science.
Just point at the screen and say "Enhance this part!" There you go. If there's something in the way, like a rock, tree, or the roof of a building, just say "Enhance it again" and you'll get all the resolution you need.
If that isn't good enough for you then maybe you could create a GUI interface using Visual Basic to do the job for you.
Would TV lie to me about this kind of thing?
My own was using lamberts cosine law to gather angular information on leg position by the light patterns reflected off the thigh of someone walking directly towards the camera.
The problem with gait recognition is, AFIAK, it's not really been proven to be a decent biometric - i.e. I'm not sure it's really all that unique, not without measuring things at a very high resolution, which probably isn't going to be possible either from space or with the current install-base of cctv cams.
Anyway, scary stuff if it does work.
I like how yet again ``spotting terrorists'' is an euphemism for ``spotting everyone else, too''. I habitually substitute ``spotting YOU'' and honestly think of all the good it would do.
Yes, there's useful stuff in there, but again only if those watching you can be trusted. This has been said often enough before and still people score cheap headlines with the same fallacy.
Anybody spot the shadow of a flying pig yet?
So... um, you've got a "terrorist" under tight enough surveillance that you can build a "gait profile", but you're not arresting or just outright executing them?
Admittedly, I support this effort. Once complete, the DHS can take its rightful place as the Ministry of Funny Names and Walks.
c.
Log in or piss off.
5-10 cm is 1985 resolution, dude. About the time they got bought by Bournes (now Recon/Optical, Inc.), engineers from Chicago Aerial Industries were bragging at MIT meetings in Chicago that we'd never know the resolution of the Keyhole series. Recon, the successor to Chicago Aerial Industries now HQ'd in Virginia, has dominated the industry ever since CAI cameras detected Soviet missiles in Cuba in October, 1962.
And from the same sources, the original Hubble "mirror flaw" occured because they shipped a Keyhole part by mistake. Not hard to believe since they built both systems. Left unsaid was how similar the Hubble/Keyhole airframes were.
23 years later, after spending gadzillion bucks inventing & perfecting adaptive/active optics and instant digital signal processing we certainly are being observed even more closely.
Go ahead, ding a Senior Citizen for trolling... I'll soon be dead anyway.
Bullshit and strawmen, whether intentional or not. The objections to false positives have more to do with statistics, than with slippery slopes or anything else.
E.g., let's say I have a system which can look at photos from the security cameras, and tell you if a face or gait in the crowd matches a terrorist profile with 99% accuracy. (Which is actually a lot higher than what most of these snake oil systems get.) The problem in that case isn't that it lets 1% of the terrorists go. It's that it also creates 1% false positives out of people who aren't, for just one terrorist's photo. Apply that to just one airport, say the JFK, with its almost 60,000 passengers per day. If you get exactly one photo of each passenger, that's 600 false positives per day, in just one airport, for just one terrorist. But more likely you'll have everyone caught by several cameras during their trip to the airport, so the number multiplies accordingly.
Now feed it a database of several tens of thousands of known criminals, suspects, etc, and watch the number of false positives explode. Given that accuracy, just 100 photos are enough to match a majority of the passengers at one point or another.
At some point you can simply swamp the security with false positives, to the point where it's worse than useless.
And it's not just a hypothetical scenario, it's what airport security people themselves have said about previous trials with face recognition system. That they're crap and worse than useless. Would you accuse those too of being paranoid and slippery-slope types, or just accept that they probably know their job enough to know when a gizmo isn't helping it?
So basically spare me the bullshit about "nirvana fallacies" and "paranoid liberals". Learn what the real problem is, before talking out the arse about.
A polar bear is a cartesian bear after a coordinate transform.