9 ms·

I'm not the original author, however, ages ago I invented what's now being called "acoustic camera". (Specifically, the SOTA on the math side for precision, ac

• _trampeltier 5y ago
  In industrial maintenace are such cameras in use to find air leaks in pneumatic. The model from Fluke is something like 20k USD. Because of this super high price, I don't know anybody who has a such model. So ask another company, if they are interested.
• paulirwin 5y ago
  Not saying it's exactly the same thing, as I don't think a video overlay was involved, but I know someone that got their PhD in this area in the 1970s and had a long career working for a U.S. military contractor doing this. The U.S. military has a significant interest in acoustic beamforming, both in the air and underwater, for obvious reasons.
  • loxias 5y ago
    Oh absolutely! Sorry, I was excited in my typing. It's not every day you see "your baby" on HN :) Everything I built was on the shoulders of giants, and lol, I didn't invent beamforming itself (of course). The problem I have trying to find the niche application is that there's not much (at least, that I could think of) where you can have high quality audio data, but where a simple camera wouldn't work. Also, full imaging (as opposed to just tracking the largest/loudest source via TDOA) is quite different math, stupendously more computationally intensive.
    • R0b0t1 5y ago
      Industrial automation monitoring is a major commercial application. I was going to look at https://www.minidsp.com/products/usb-audio-interface/uma-16-microphone-array https://www.minidsp.com/products/usb-audio-interface/uma-16-... for doing it. Do you know what limits of detection you could get, and on what equipment? Monitoring structural vibrations is also useful, and I think is an ongoing research area. I mention this because it's possible to sell it and research it at the same time. What about synchronized cameras in different locations?
• cameron_b 5y ago
  Videoconferencing applications are implementing this in conjunction with face detection to "steer" wide angle cameras into "talking head" shots. The current tech is spooky trash, parlor trick-quality from what I've used. Every time we use some of the automatic gizmos in conference rooms, we get tickets to make it stop. Pick your favorite top video conferencing platform or camera maker and they'll want to improve what they have. The Creepy - "Just works" jump is a big one. PS., the industry trade show is happening RIGHT NOW at https://www.infocommshow.org/ https://www.infocommshow.org/
• joshmarlow 5y ago
  I have absolutely no knowledge about this domain, so this idea 1) might not be viable and 2) is not a full developed product idea - but I thought it would be fun to get your thoughts. Could you put some sound sensors inside of some mechanical structure and use the acoustics to figure out where some physical contact is happening on the outside of the structure? Specific Application: prosthetics devices that can - with only a few acoustic sensors - determine where the 'touch' was on the outside of the device. If viable, it may be similarly useful for robots - or any machine in general - that needs a low-hardware (and thus low cost) method of getting course tactile information around it's boundary.
• nyanpasu64 5y ago
  How does this compare with commercial ultrasonic flaw detection systems for physical objects?
  • loxias 5y ago
    No idea! For a few month's stipend and cost of ultrasonic parts, I can find out for you. :)
• _spduchamp 5y ago
  You want to pay the rent? Don't make a product, make a service, mainly, "WHERE IS THAT ANNOYING SOUND COMING FROM? SERVICE". People will pay you to locate sources of irritating sounds.
  • loxias 5y ago
    I have "inverse aptitude" at knowing what should be a product. :) Never trust me to know what would sell or not. In fact, "bet against whatever I think". ;) In my ideal (and in the best jobs I've had in the past), someone finds me (or I find someone) who I can share a list of "cool things I've figured out how to do, but don't know the usefulness of", and that person then tells me what to build. For your "where is that annoying sound coming from?" service, what sort of scale do you imagine, and what form factor? A handheld consumer device with a range of ~10m which points in the direction of the loudest thing? How much would you pay for such a device? (would love your thoughts in email)
  • rapjr9 5y ago
    I use handheld sound amplitude meters and spectrogram software on smartphones to track down sounds I want to eliminate. This is often for musical purposes, but also for annoying sounds. An amplitude meter can be useful for finding the source of a sound, but lower frequency sounds are not as directional, and standing waves in rooms can make a sound source appear to come from somewhere other than the source (though perhaps moving a sound camera around physically could help eliminate this ambiguity?) The spectrogram can provide evidence of a specific periodicity or frequency range that can help identify a source. However these tools while useful are not sufficient all the time and are certainly not quick to use. I've often thought it would be really useful to have something like a gunshot detector for ordinary sounds, to be able to locate sounds both indoors and outdoors. It would help in answering questions like "is that sound a bear/dog raiding my trash?", "is the fan failing in my air purifier?", "is my air conditioner rattling something nearby?", "is my fridge transmitting a low level hum throughout the house?", "is that engine noise a truck pulling up to my house or a truck climbing a hill on the nearby highway?", all problems I have actually faced. Not sure if a sonic camera can deal well with low frequency sounds, but it would certainly make it easier to deal with higher frequency sources of noises. I'd buy one on impulse for $100, with some consideration of features at $300.
• jbay808 5y ago
  It would be great if I could point something at a noisy machine and find out precisely which panel is loose and vibrating!
  • loxias 5y ago
    Really? Would it be "great" enough that you'd pay for such a device? If so how much? (would love to continue over email)
    • schiffern 5y ago
      Looks like it's found use in automotive applications for tracking down NVH (noise, vibration, and harshness) issues. https://www.youtube.com/watch?v=C18AA_nlQN8 https://www.youtube.com/watch?v=C18AA_nlQN8
    • hetspookjee 5y ago
      I’d definitely pay for it. Though I’d use it outdoors in the woods to see where birds and other critters are hiding. Though I reckon the noise will pose a challenge.
    • jbay808 5y ago
      Yes. Email sent ;)
  • ZeikJT 5y ago
    There was a thread on here a while back where people would set up cameras and be able to make a motion image showing what parts moved with a regular frequency. Was being used at factories to determine points of failure via vibration. Can't find the thread now though.
    • ZeikJT 5y ago
      Aha, it was a video by Steve Mould: https://www.youtube.com/watch?v=rEoc0YoALt0 https://www.youtube.com/watch?v=rEoc0YoALt0
• robmiller 5y ago
  I am an acoustics consultant who designs buildings with architects, then sees them through construction. Doors intended to isolate noisy rooms regularly underperform, whether due to manufacturing or installation problems. Lots of fingerpointing when we call it out on project sites, and having a camera show the weaknesses due to the perimeter gasketing, frame, door leaf, or wall construction surrounding the door would provide the necessary visual for contractors to see the problems we are pointing out.
  • loxias 5y ago
    I think you're talking about a different problem, though that one could also be helped with the right tool. After setting up the array, once could answer questions like "where is that darn squeak coming from!", and even characterize the undesirable noise, both spatially and spectrally. You could also measure how effective noise isolation materials are, but I don't see what the spatial information gets you. However, if weaknesses due to "perimeter gasketing, frame, door leaf, or wall construction" result in some sort of localized noise, then a system like this would certainly pinpoint it.
    • robmiller 5y ago
      Yes, this is in reference to noise passing through a door that is localizable. Typically we would play pink noise (broadband, equal energy per octave band) on one side and listen for "hotspots" on the quiet side. I would wonder about the precision of being able to tell in the image the contribution of the door frame from the perimeter gasketing. Acoustic cameras like from Noiseless Acoustics are on the market though they seem to be marketed to industrial customers. There are similar mapping systems using a scanning mic like from Soft dB.
      • loxias 5y ago
        Ah! In that case yeah, this tech could possibly help. At least, I'd love to give it a shot! (I hope you don't mind an email from me later...) It's sensitive enough to noise that I can pick up (and locate) the air vents in a room, even when the sound is at the threshold of hearing. Noise (pink and white), and even more so MLS (maximum length sequence) really "jumps out" (it's very obvious), well below my threshold of hearing. There's so many interesting areas of research I've never had the time/money to fully investigate. I'd love to play with an "active" system, not just "passive", with a goal of experimentally finding modes of resonance of objects in a room. I bet once can tell the relative contribution to noise of one physical object over another, but I don't know enough about construction to know if one would be able to separate the door frame from the perimeter gasketing. You do need line of sight for it to work. At the least, you'd have a way to quantify the sound leak, with numbers and reproducibility. FWIW the Noiseless Acoustics camera costs ~$18k(!)
• beachy 5y ago
  A "squid game"-style kids game. Kids must tiptoe across in front of the camera. If they make any noise, the camera uses a powered gimbal to aim a hose at them and squirt them with water. And a terrifying siren goes off.
• wpietri 5y ago
  How precise can I make it? And how do I think about optimal microphone layout? I've been considering putting multiple microphones on one side of the house to track birds. I mainly want to isolate the audio for recognition. But setting up a PTZ camera to get good shots would be even cooler.
  • loxias 5y ago
    > multiple microphones on one side of the house to track birds. This was one of my first at home demos! Tracking birds and cars. If you want to get started DIY and figuring it out yourself, try about 5 microphones, each 1m apart. The trick is having all the mics in line of sight to the object in question. Otherwise you're left with doing an "intersection of angles" method, which is much simpler, but horrible in terms of precision. In a later demo I used a PTZ laser pointer to track the moving sound sources, so, it's at least possible!
    • ggm 5y ago
      sound tracking + laser == mosquito zapper
    • wpietri 5y ago
      Thanks! And do you have suggestions about how to think about extracting relatively pure sound from that point? It seems intuitive to me that it's doable, and I'm sure there must be a lot of work already done, but I'm clearly not googling the right terms.
• grayfaced 5y ago
  What kind of range/sensitivity could you get outdoors? Maybe spotting deer for hunters. (caveat I'm not a hunter)
• anitil 5y ago
  I would suggest asset protection. I used to work for a company (Droneshield) that would provide protection from drone-based sabotage/intelligence gathering/smuggling. It's a big field, but if you could, for instance, set up an alert for when a noise source crosses a property border, or when something that sounds like a human comes within x meters of a particular building, I think that would be valuable. I'm no longer there, but happy to talk if you're interested.
  • loxias 5y ago
    This sort of tech was really good at tracking drones. Neat thing about drones is they put off so much waste audio, rich with information. I know very little about drones, but, in a demo I made years ago (trying to convince someone to give me money for using this in a drone defense product), I was able to "fingerprint" different drone models, even sometimes distinguish between two different drones of the same model. As long as there's line of sight, you can sometimes "see", in the data, slight changes in the speed of the propeller, as well as the rough "shape" of the drone itself. But for all those applications, even though I love sound, I always think to myself.... "wouldn't a pair of cheap cameras do this better?" :) > no longer there, but happy to talk if you're interested. Thanks!
    • anitil 5y ago
      > "wouldn't a pair of cheap cameras do this better?" That's part of where they've gone (though the cameras are far from cheap) as well as RF, with some AI magic sprinkled on top. I wouldn't suggest doing drone defense, but smaller-scale asset protection might be more approachable. There's what, 3000 local governments in the US? I'm sure a lot of them have had a tractor stolen from a road construction site. Or maybe if they lease their equipment you could sell a solution to the leasing company.
• socatacos 5y ago
  I have seen a similar product used in automotive acoustic wind tunnels to help identify the locations of acoustic hot spots in the flow around a car.