By analysing the movements of human shadows in aerial and satellite footage, JPL engineer Adrian Stoica 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.Our fingerprints are unique; no matter how similar they may be, they will still be different. Since our hands are the tools our mind uses to create things, this entails that what each person does will be created in a unique way... it's shape will have our individual "fingerprints" all over it.
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. That's not true of shadows, though, Stoica told a security conference in Edinburgh, UK, last month. Shadows, he says, provide enough gait data to deduce a positive ID. To prove it, he has written software that recognises 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. In tests on footage shot from the sixth floor of a building, Stoica says his software was indeed able to extract useful gait data.
I remember reading somewhere that a person's toes have similarly unique markings on them as our fingertips do, but it's rather impractical to catalogue them or use them to identify people, because we never go around barefoot. The romantic in me finds it fascinating that our unique feet propel us forward in unique ways, creating unique rhythms, leaving unique marks attesting to our irreplaceable uniqueness, and our consequent value as individuals.
But then, people are always saying that I march to a different drummer...
[thanks to MHA at Flares Into Darkness]