MIT Finds Can Hear What Is Going On In A Room By Video Recording Vibrations Of A Potato Chip Bag

Posted on Aug 5 2014 - 9:53pm by Steve M

MIT bag of chips vibration microphone

Yep, you read that long ass title correctly. The smart kids at MIT have found a way to use a high-speed camera to video an object in a room (through a window let’s say) and decode the vibrations in to an audio track. In other words… if they can see inside your car, house, or office they can pretty much hear what is going on inside the room.  How do they do this?  Here is what the smart kids have to say about this –

When sound hits an object, it makes distinct vibrations. “There’s this very subtle signal that’s telling you what the sound passing through is,” said Abe Davis, a graduate student in electrical engineering and computer science at MIT and first author on the paper. But the movement is tiny – sometimes as small as thousandths of a pixel on video. It’s only when all of these signals are averaged, Davis said, that you can extract sound that makes sense. By observing the entire object, you can filter out the noise.

The results are certainly impressive (and a little scary). In one example shown in a compilation video, a bag of chips is filmed from 15 feet away, through sound-proof glass. The reconstructed audio of someone reciting “Mary Had a Little Lamb” in the same room as the chips isn’t crystal clear. But the words being said are possible to decipher.

This is similar to laser microphones which pick up the vibrations on windows and the like to decode the audio in the room. The main difference being you can use any high-speed camera.  Very cool.  Video of this MIT research technology in action after the break.


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