Track Terrorists By Their Shadows

JPL: Use Sats To Track Terrorists By Their Shadows

By Noah Shachtman
September 04, 2008 2:18:00 PM
Categories: Biometrics, Space, You can run...
Courtesy Of Wired.com

Look out, jihadists. The Great Satan is going to stare down from space, and pick you out by the way you walk.

That's the idea, at least, from Jet Propulsion Laboratory engineer Adrian Stoica, who claims he's developed a system for "gait recognition" -- IDing someone, by their stride -- using overhead imagery. Ordinarily, "video taken from above shows only people's heads and shoulders, which makes measuring the characteristic length and rhythm of a person's stride impossible," New Scientist explains.

[But shadows] "provide enough gait data to deduce a positive ID. To prove it, [Stoica] has written software that recognizes human movement in aerial and satellite video footage. It isolates moving shadows and uses data on the time of day and the camera angle to correct shadows if they are elongated or foreshortened. Regular gait analysis is then applied to identify people.

Gait recognition has a certain appeal, Stoica once wrote, because "it offers potential for recognition at a distance or at low resolution, when other biometrics might not be perceivable... Recognition can be based on the (static) human shape as well as on movement, suggesting a richer recognition cue."

The idea of identifying terrorists by their walks enjoyed a brief moment of (in)famy in 2002, when it was included in Darpa's notorious Total Information Awareness project. "Tony Blair has pledged the full coöperation of the Ministry of Silly Walks," the New Yorker quipped, at the time. Researchers from Columbia University to MIT to Georgia Tech took a swing at stride identification before Darpa dropped the effort.

[Photo: Defence.gov.au]