Here's one technique James Bond probably wishes he'd had more than a few times. Researchers managed to reconstruct voices and music being played in a room just from video of the minute vibrations produced in nearby leaves and other objects. The vibrations are caused by the sound waves, and a high-speed camera, trained on thin surfaces (an empty bag of potato chips, for instance) as they move, can work out the frequency and timing of those sound waves.
"Mary had a little lamb" was as clear as a bell, reflected in some plant leaves, and Queen's "Another One Bites the Dust" could be detected just by close visual inspection of a pair of earbuds playing it — no microphones allowed, of course. The technique won't work if the object being observed is moving for another reason, like wind, and there's room to improve the signal-to-noise ratio. But just the possibility of having your voice recorded and identified just by the way a candy bar wrapper moves may be enough to ratchet up anyone's paranoia. The study, conducted by researchers at MIT, Microsoft and Adobe, will be presented at this year's Siggraph computer graphics conference.
— Devin Coldewey, NBC News