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Title: SCIENCE! Post by: Viin on March 31, 2016, 06:28:31 PM Since we don't have a general purpose SCIENCE! thread, well, here you go!
I ran into this listening to the TED Radio Hour podcast.. Capturing sound from object vibrations (random bag of chips!): https://www.ted.com/talks/abe_davis_new_video_technology_that_reveals_an_object_s_hidden_properties?language=en (https://dl.dropboxusercontent.com/u/42220/Misc/ted_abe_davis.png) Imagine using a security video feed to reconstruct the conversation in a room, simply by analyzing the movements of a random nearby object. Title: Re: SCIENCE! Post by: Goreschach on March 31, 2016, 06:55:03 PM Imagine using a security video feed to reconstruct the conversation in a room, simply by analyzing the movements of a random nearby object. Literally impossible. The nyquist limit of the video framerate would prevent sampling of the typical vocal range of human speech. Haven't even watched the video yet, but I'm assuming they were using hi speed cameras, like the ones mythbusters use sometimes, to record with. Title: Re: SCIENCE! Post by: MahrinSkel on March 31, 2016, 07:04:30 PM Yeah, you need a sampling rate at least twice (and more practically 4x) that of the frequency you are trying to record. Since for standard cameras that is 60 frames per second, you're short an order of magnitude of what you would need to reconstruct a voice (human voices range from 80-250hz).
Not to mention that even 4K resolution probably wouldn't be adequate unless the resonant membrane was extremely close to the camera. Easier just to have a microphone. --Dave Title: Re: SCIENCE! Post by: Furiously on March 31, 2016, 07:07:41 PM Something like a laser and a window??
Title: Re: SCIENCE! Post by: Viin on March 31, 2016, 07:49:22 PM Sorta like a laser and a window, but different. Watch the video before you start spouting about things you don't know ;)
Title: Re: SCIENCE! Post by: MahrinSkel on March 31, 2016, 08:30:47 PM Sorta like a laser and a window, but different. Watch the video before you start spouting about things you don't know ;) 3:30 in the video: "What if we record them with a high speed camera?"EDIT: Later he talks about using a standard camera, but the audio they are getting is so distorted that it doesn't sound like anything at all. And all of this is with the cameras zoomed in on very good resonators (chip bags, maybe a fake plant). EDIT2: The structural analysis and CGI potentials are actually interesting, as is the idea of reading bio-signs from standard video (a camera that could detect apnea in infants could be the first major counter to SIDS). But the 'surveillance' potential is practically nil compared to what equivalent processing could do with even poor quality audio. --Dave Title: Re: SCIENCE! Post by: Viin on March 31, 2016, 08:39:56 PM Keep watching.
Title: Re: SCIENCE! Post by: Yegolev on December 16, 2016, 07:44:15 AM Science.
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