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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.
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.
How does it account for any type of foot, ankle, or leg injury that doesn't require crutches?
How about someone throwing a handful of rocks in the shoe to forcibly change their gait?
How about someone that is conscientious enough to change their gait at every new location?
(I cannot lay claim to these ideas myself - I read Cory Doctrow's "Little Brother" - a very good novel that is licensed under the Creative Commons model and is available at http://craphound.com/littlebrother/ )
This just reeks of wasted money and more governmental control.
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.