The researchers obtained useful audio information by studying the vibrations of other objects, such as plant leaves, aluminum foil and a glass of water. This audio information is due to the ability of sound to cause objects to vibrate when it hits them. This vibrational motion brings about very small, visual signals that are not visible to the naked eye.

Researchers at MIT, Microsoft and Adobe have invented a new algorithm that can reconstruct human-understandable sound information by recording and analyzing the tiny vibrations of objects such as potato chip bags.

Such technology makes it easier for scientists to know what words someone is saying. This would raise new privacy concerns. When sound hits an object, it can cause the object to vibrate," said Abe Davis, a graduate student at MIT and the first author of the paper. This vibrational motion brings a very small, invisible visual signal to the naked eye. People don't realize that such information exists."

In one experiment, the researchers recovered sound information using a bag of potato chips nearly 5 meters away from the soundproof glass. In another experiment, the researchers obtained useful audio information by studying the vibrations of other objects, such as plant leaves, aluminum foil and a glass of water.

The method used by the researchers usually requires the use of high-speed cameras that capture thousands of frames per second. Through this method, researchers can know the number and gender of speakers in the room. If the speaker's voice information is obtained in advance, then the identity of the speaker can also be identified.