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Extracting Audio From Visual Information

Posted by samzenpus on from the what-the-bag-says dept.

rtoz writes 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 (video) photographed from 15 feet away through soundproof glass.

6 of 142 comments (clear)

  1. Not surprising by Z00L00K · · Score: 4, Insightful

    Measuring the vibrations of windows or other items was used already 40 to 50 years ago by spy agencies, so I wonder if this isn't something that has been re-discovered?

    --
    If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
    1. Re:Not surprising by Hamsterdan · · Score: 5, Insightful

      The countermeasure for laser listening was to install the windows inside a pipe *frame* and play music in the pipes. Using an object inside the building to extract audio defeats that countermeasure. This is 2014, do not expect any privacy, especially from government agencies...

      --
      I've got better things to do tonight than die.
    2. Re:Not surprising by timeOday · · Score: 4, Insightful

      Well, even a normal microphone is "just" measuring the linear displacement of a membrane over time, so clearly the important distinction is how you measure it. A laser range-finder is different from a microphone, and a video camera is different from a laser range-finder.

  2. Re:Now my tin-foil hat... by JackieBrown · · Score: 4, Insightful

    The hat is a trick!

    The reason they want you to wear foil is so that the sound can bounce off it.

  3. Re:Requires a very high speed camera by interiot · · Score: 4, Insightful

    30 Hz is far below the Nyquist rate (6800 Hz, going by POTS specs), so no, that wouldn't be possible without some fundamental changes in our understanding of information theory and physics.

  4. Re:Now my tin-foil hat... by fuzzyfuzzyfungus · · Score: 4, Insightful

    Worse than that. If there's a metal foil involved, vibration measurement should be doable with RF as well as light. Only with a next generation reduced radar cross section geometries and RF absorbent materials can a truly secure tinfoil hat be constructed.

    Unfortunately, walking around with what appears to be a small F-117 attached to your head offers limited visual camouflage potential and may prove counterproductive in your attempts to avoid Their surveillance.