4 ms·

Also, I think a big advantage for the camera-based solutions is that they're totally passive, while laser-based need to interact with the object.

• Zigurd 9y ago
  To make a camera-based solution practical, it seems like one would neeed a specialized camera, for modest resolution, but very high frame rate. Without enough frame-rate, you can't capture high frequencies. Even if speech could be discerned from a spectrum that rolls off at 300hz, well under the peak energy of a typical human's speech, you would still need many hundreds of frames per second.
  • fisherjeff 9y ago
    If you watch the video at the end, you'll see that they actually exploit the fact that CMOS pixels are read out sequentially and use the data from each row to extract surprisingly decent high frequency data from even 60 Hz video!
  • mikeash 9y ago
    They article says they were able to use the rolling shutter on standard cameras to extract data at a much higher frequency than the nominal framerate would allow.
  • regularfry 9y ago
    The article talks about this. The rolling-shutter effect means that you can get information out at higher than frame rate.