Algorithm recovers speech from vibrations of potato-chip bag filmed through soundproof glass

[Jim__]

From phys.org:

Researchers at MIT, Microsoft, and Adobe have developed an algorithm that can reconstruct an audio signal by analyzing minute vibrations of objects depicted in video. In one set of experiments, they were able to recover intelligible speech from the vibrations of a potato-chip bag photographed from 15 feet away through soundproof glass.

In other experiments, they extracted useful audio signals from videos of aluminum foil, the surface of a glass of water, and even the leaves of a potted plant. The researchers will present their findings in a paper at this year's Siggraph, the premier computer graphics conference.

"When sound hits an object, it causes the object to vibrate," says Abe Davis, a graduate student in electrical engineering and computer science at MIT and first author on the new paper. "The motion of this vibration creates a very subtle visual signal that's usually invisible to the naked eye. People didn't realize that this information was there."

...

Reconstructing audio from video requires that the frequency of the video samples—the number of frames of video captured per second—be higher than the frequency of the audio signal. In some of their experiments, the researchers used a high-speed camera that captured 2,000 to 6,000 frames per second. That's much faster than the 60 frames per second possible with some smartphones, but well below the frame rates of the best commercial high-speed cameras, which can top 100,000 frames per second.


more ...

[arcane1]

1. Cool! And maybe a little creepy too

[PoliticAverse]

2. From now on I'm only buying chips that come in an acoustic foam bag. n/t

[Ilsa]

3. Reminds me of a scene from Eagle Eye in which

the humans (SecDef, military officer, etc) are discussing national security in soundproofed room with plexiglas or something. They unplugged the telephone in the room, but the Artificial Intelligence computer spying on them interpreted the soundwaves in a cup of coffee to eavesdrop on them.

Fiction becomes reality.

[Brother Buzz]

15. That was based on reality, not fiction

Laser microphones can read sympathetic sound vibrations from objects in a room from a distance, although the effectiveness is questionable. Straight audio.


This device converts optical footage to acoustic sound with the help of some slick software.

[Ilsa]

16. I think the movie was made in 2011 or 2010. Were the

Laser mics able to do that then?
Creeps me out anyway.

[Brother Buzz]

17. Infrared beam microphones were used first

Back in the seventies, the military guarded against them with a 'noise' generator doohickey attached to the building; white noise canceled out sympathetic voice vibrations. Visualize classified military briefings being held in the basement surrounded by HVAC equipment. Well, it wasn't that loud, but it did put me to sleep every time.

[LiberalEsto]

4. The day the chips start ratting on us ...

[eppur_se_muova]

5. Interesting -- no laser beam required.

Eavesdropping with lasers bounced off of vibrating surfaces (usually window glass) has been in use for a long time; US embassy windows have been made with special glass which scatters and decoheres light for a long time.

One of the textbooks designed to train security personal contains a section on such devices. It says one can be built using a General Electric H1A1 laser, which radiates about 35 watts of power in the infrared band. It is pulsed with a simple transistor circuit at 10 kilohertz. The receiver is an astronomical reflecting telescope bought from Edmund Scientific Company. A photomultiplier tube, which turns the pulsed infrared signal into a series of electrical pulses, is mounted in place of the eyepiece. The output of the photomultiplier is then fed to an amplifier to recover the voice signal from within the room.

http://www.bugsweeps.com/info/bugsweepers.html

This is actually a description of an early, fairly crude version of this device -- older than desktop computers.

[toby jo]

6. How come every time these cool inventions come up they immediately get used

to get the little people? Let's use this to control people better, line them up, make them behave for us.

I hope they get a medical advancement out of this. Or maybe something that will help us in space exploration.

[Blue Owl]

7. That's some crisp audio alright

n/t

[BlueJazz]

9. LOL!

[littlemissmartypants]

11. DUsy. n/t

[packman]

8. Cat purring explained

So when I talk to my cat he purrs. Ahh, so. "When sound hits an object, it causes the object to vibrate,"

[Ikonoklast]

13. Your cat isn't purring at you, he's singing your death song.

Prepare yourself.

[ThoughtCriminal]

10. See! This is why they WANT us to wear tin foil hats!

So they can record us when the hats vibrate!



The government starts conspiracy theories to convince us to wear them.


http://thoughtcrimewave.blogspot.com/2008/01/tin-hats.html

[JDPriestly]

12. Wow! Soon they will be able to read minds. I'm serious.

Thinking is also a vibration. I understand that they are now looking at the vibrations reflected in objects that absorb and reflect sound vibrations, but . . . . they will find a way to read human minds.

[Spitfire of ATJ]

14. All the more reason to blast the stereo as you whisper to each other.

[JackInGreen]

18. As if I wasn't paranoid enough

Now I have to fear my bag of plain Lays chips. Shit.