Visualizing Sound

In the CACM:
" .... In the movies, people often discover their room is bugged when they find a tiny microphone attached to a light fixture or the underside of a table. Depending on the plot, they can feed their eavesdroppers false information, or smash the listening device and speak freely. Soon, however, such tricks may not suffice, thanks to efforts to recover speech by processing other types of information.

Researchers in the Computer Science and Artificial Intelligence Laboratory at the Massachusetts Institute of Technology (MIT), for instance, reported at last year's SIGGRAPH meeting on a method to extract sound from video images. Among other tricks, they were able to turn miniscule motions in the leaves of a potted plant into the notes of "Mary Had a Little Lamb," and to hear a man talking based on the tiny flutterings of a potato chip bag.     ... "