Researchers Develop a Low-Cost Visual Microphone (phys.org) 23
alternative_right shares a report from Phys.org: Researchers have created a microphone that listens with light instead of sound. Unlike traditional microphones, this visual microphone captures tiny vibrations on the surfaces of objects caused by sound waves and turns them into audible signals. In the journal Optics Express, the researchers describe the new approach, which applies single-pixel imaging to sound detection for the first time. Using an optical setup without any expensive components, they demonstrate that the technique can recover sound by using the vibrations on the surfaces of everyday objects such as leaves and pieces of paper. [...]
To demonstrate the new visual microphone, the researchers tested its ability to reconstruct Chinese and English pronunciations of numbers as well as a segment from Beethoven's Fur Elise. They used a paper card and a leaf as vibration targets, placing them 0.5 meters away from the objects while a nearby speaker played the audio. The system was able to successfully reconstruct clear and intelligible audio, with the paper card producing better results than the leaf. Low-frequency sounds (1 kHz) showed slight distortion that improved when a signal processing filter was applied. Tests of the system's data rate showed it produced 4 MB/s, a rate sufficiently low to minimize storage demands and allow for long-term recording. "Currently, this technology still only exists in the laboratory and can be used in special scenarios where traditional microphones fail to work," said research team leader Xu-Ri Yao from Beijing Institute of Technology in China. "We aim to expand the system into other vibration measurement applications, including human pulse and heart rate detection, leveraging its multifunctional information sensing capabilities."
To demonstrate the new visual microphone, the researchers tested its ability to reconstruct Chinese and English pronunciations of numbers as well as a segment from Beethoven's Fur Elise. They used a paper card and a leaf as vibration targets, placing them 0.5 meters away from the objects while a nearby speaker played the audio. The system was able to successfully reconstruct clear and intelligible audio, with the paper card producing better results than the leaf. Low-frequency sounds (1 kHz) showed slight distortion that improved when a signal processing filter was applied. Tests of the system's data rate showed it produced 4 MB/s, a rate sufficiently low to minimize storage demands and allow for long-term recording. "Currently, this technology still only exists in the laboratory and can be used in special scenarios where traditional microphones fail to work," said research team leader Xu-Ri Yao from Beijing Institute of Technology in China. "We aim to expand the system into other vibration measurement applications, including human pulse and heart rate detection, leveraging its multifunctional information sensing capabilities."
Re: Incomplete report (Score:5, Interesting)
Or even a high speed camera. Pretty big improvement on the old laser mike...
Re: (Score:3)
What (Score:1)
I used devices like this in Desert Storm. No laser just point it at a wall or window what ever.
Re: (Score:2)
And they were probably $100,000 a pop.
Now they're commercial and getting much cheaper and more available as the tech becomes mainstream.
Like, pretty much, almost anything in high-end military, Formula 1 or rally driving, etc. etc. etc.
Expensive thing deployed as brand-new tech to get a slight edge in a billion dollar business becomes off-the-shelf cheap junk tech to help granny snoop on grandpa. It's really not unusual.
Re: (Score:2)
You're only off by 4 decimal places. This is over a decade old:
https://www.instructables.com/... [instructables.com]
Re:Won't work in the dark (Score:5, Interesting)
So confused (Score:1)
Re: So confused (Score:2)
Let go of your feelings, Luke
Re: (Score:2)
It'll look impressive. The sound will, for obvious reasons, be like ass. (Researchers spent over a hundred years researching the best materials, and the shapes to make them, to use as microphone diaphragms, turns out rocks, bananas, spoons, cuddly bears, nearby people, onions, yogurt, and crates of copy paper, are not optimal at vibrating at all frequencies.)
But it's nonetheless a cool experiment even if it's not (see other posts) a completely new concept. It is, however, a new way of implementing that conc
still only exists in the laboratory...... (Score:2, Interesting)
Re: (Score:2)
Open The Pod Bay Doors, Hal (Score:2)
Just picturing all those robot cleaners and flying micro drones out there.
Not really new (Score:3)
A method of hearing whats going on inside a building uses a LASER shined on a window and has been around for at least 20 years. The reflections are modulated by sound inside, allowing the listeners to hear conversations and other sounds from miles away.
"Clear and intelligible audio" (Score:2)
This is pretty cool, but "clear and intelligible audio" is overselling it. The examples are noisy as fuck.
How does a traditional microphone work? (Score:2)
"Unlike traditional microphones, this visual microphone captures tiny vibrations on the surfaces of objects caused by sound waves and turns them into audible signals."
That's exactly how traditional microphones work. Also, optical listening devices have been around since the 1960s.
Re: (Score:2)
You might note the lack of the word "other" in the quoted sentence in the post you responded to. The membranes in a traditional microphones are objects.
But you knew that . Why cheekily be dumb?
The Photophone (Score:2)
https://en.wikipedia.org/wiki/Photophone [wikipedia.org]
Invented, in part, by Alexander Graham Bell.
I used to work at an outfit that had a big conference room, with big beautiful windows, that faced out across an airfield into a wooded area (good hiding places). In order to mitigate such optical surveilance, the windows were equipped with small piezoelectric speakers. Driven with (I'm guessing) white noise.
Re: (Score:2)
I used to work at an outfit that had a big conference room, with big beautiful windows, that faced out across an airfield into a wooded area (good hiding places). In order to mitigate such optical surveilance, the windows were equipped with small piezoelectric speakers. Driven with (I'm guessing) white noise.
If I'm understanding the article correctly, the conference room window mitigation wouldn't work against this. It doesn't rely on vibrations of the windows. Instead, you'd just need a piece of paper inside the room, lit by ordinary lamps. As long as the light reflecting off the paper could pass through the windows unmodified (i.e. the windows provide clear visibility) the white noise vibrations of the windows would have no effect.
On the other hand, lightweight curtains that blocked the view through the w