Amazing! Scientists Recover Sound by Analyzing Tiny Vibrations in Solid Objects

https://www.youtube.com/watch?v=ytcUmFx0BLg

Wow, who knew...sound causes the surfaces of objects to vibrate.

http://en.wikipedia.org/wiki/Laser_microphone

http://en.wikipedia.org/wiki/Loudspeaker

and of course the famous

http://en.wikipedia.org/wiki/Thing_(listening_device)

I'm sure the researchers at MIT are aware that the technology to record sound through vibrations using the above linked lasers, etc, is not new. What may be new however is that this analysis is coming from high speed video recording of the object.

I am sure they are too. It is well known that sound causes objects to vibrate, with advances in sensor technology and computation software weaker vibration forces (by way of video) are now apparently able to be decoded.

My only point is that this sort of thing is not entirely new.

This is really old technology.

The CIA used a similar technique with a laser aimed at windows to "hear" conversations in that building.

The reflected laser beam would be doppler shifted by the audio vibrations on the glass and demodulated to reproduce the original audio.

That was in the 1960s or 1970s. 40 to 50 years later I am sure the technique has long been improved upon.

This is not so amazing after all.

WHAT?! SOUND IS VIBRATION?????

They woke me up for that gem? Didn't we all know that already?

Blimey if they fine tune the effect they could make ... errr a microphone (slaps furry head with paw)

When you actually consider it a crisp packet is pretty much optimal. If they did it with a brick or a squirrels ar$e I'd be impressed.

And regarding the title... a crisp packet is a solid object? Discus.

Del (zzzzzz)

What is even more amazing are two things: first when you tell kids today that "Mary had a little lamb" they would respond by saying "ewe, I am a vegan" [ewe, that's funny]. And the second amazing thing is that someone at MIT knows how to play Mary had a little lamb.

S.R.V. version ? yeah, it'd be amazing.

You guys are hard to impress. The really interesting thing here is that they didn't use a laser beam reflected from the object. They used a digital camera in which the movement of the vibrating leaves of the plant was less than a tenth of a pixel. They calculated the vibration of the leaves by observing changes in the pixels across the entire picture. Naturally in order to get a high enough sampling rate they had to use a high speed camera with thousands of frames per second.

Then they did something even more clever. They used a standard cell phone camera to detect movements of vibrating objects, without using thousands of frames per second. In essence they figured out how to make an ordinary, 30 fps, high definition camera in a cell phone into a "microphone" that can "listen" to conversations behind a soundproof window.

I know someone who already covers his iPhone camera with electrical tape, because a hacker can use it to spy on him. This takes that level of spying and ups it an order of magnitude.

Never heard of the IPhone having a microphone then! There is Nerds and there is even more Nerds.

Always wonder what they see when they switch the camera on when its in your pocket!

Hard to impress?

Sure get something new. With 30 FPS they can still tell if it is a woman or man speaking. Gosh I think the camera picture would be of better use here!