Posted on 08/06/2014 8:42:07 AM PDT by servo1969
(Videos)
When sound hits an object, it causes small vibrations of the object’s surface. We show how, using only high-speed video of the object, we can extract those minute vibrations and partially recover the sound that produced them, allowing us to turn everyday objects—a glass of water, a potted plant, a box of tissues, or a bag of chips—into visual microphones. We recover sounds from highspeed footage of a variety of objects with different properties, and use both real and simulated data to examine some of the factors that affect our ability to visually recover sound. We evaluate the quality of recovered sounds using intelligibility and SNR metrics and provide input and recovered audio samples for direct comparison. We also explore how to leverage the rolling shutter in regular consumer cameras to recover audio from standard frame-rate videos, and use the spatial resolution of our method to visualize how sound-related vibrations vary over an object’s surface, which we can use to recover the vibration modes of an object.
(Excerpt) Read more at people.csail.mit.edu ...
used surreptitiously since the ‘70s, at least.
Good, good, good vibe ray shuns!
(You’re welcome.)
They have been using lasers on window glass for decades............
“allowing us to turn everyday objects—a glass of water, a potted plant, a box of tissues, or a bag of chips—into visual microphones.” Windows, too.
Decades ago, third floor, E-ring of the Pentagon, electrical vibration devices were attached to the windows to distort and make unreadable any vibrations from people speaking in the room.
Aim a laser at an unprotected window and variations in the laser return can be used as a microphone to pick up speech.
Yes, the CIA famously developed a device that used a laser to detect the sound vibrations on a piece of glass, so they could point it at the windows of the Russian embassy and hear what was being said inside.
Interesting way of avoiding the Nyquist limit with a 30 frame per second video.
The cops already use this with lasers on windows and walls. But like any good authoritarian would say...”If you haven’t done anything wrong, you have nothing to worry about. Trust me...”
They did it to us, first, with a passive device embedded in a “gift.”
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