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I would request that a crowd as technically sophisticated as HN move past marketing claims when discussing this system. "Gunshot detection" is pure marketing.

by loteck 3y ago

I would request that a crowd as technically sophisticated as HN move past marketing claims when discussing this system. "Gunshot detection" is pure marketing. The devices are hot mics — public audio surveillance. The software layer triggers alerts on loud noises, which are sent off to a facility that is little more than a call center, for characterization by a human worker there. This system detects door slams and popped volleyballs just as well as it detects gun fire (which is to say, imperfectly on all counts).

Aurornis 3y ago
> This system detects door slams and popped volleyballs just as well as it detects gun fire (which is to say, imperfectly on all counts). Sound classification moved far beyond what you’re claiming years ago. If you set the threshold at “imperfectly” then no system will ever meet your bar, because perfect is an unreasonable threshold. However, the claim that we’re unable to differentiate between gunshots and car doors is extremely incorrect.
- loteck 3y ago
  Shotspotter falsely classifies popped volleyball as gunshot: https://www.wtol.com/article/news/local/false-shotspotter-alert-in-east-toledo-tuesday/512-75fb9bb6-b9cf-49dd-889e-d31782ed9967 https://www.wtol.com/article/news/local/false-shotspotter-al... Slamming doors: https://www.axios.com/2022/04/07/campaign-zero-against-shotspotter-crime https://www.axios.com/2022/04/07/campaign-zero-against-shots... This list can go on. Jackhammer, nail gun, normal hammers. https://voiceofsandiego.org/2020/09/22/shotspotter-sensors-send-sdpd-officers-to-false-alarms-more-often-than-advertised/ https://voiceofsandiego.org/2020/09/22/shotspotter-sensors-s...
  - jacurtis 3y ago
    Yes there are false positives. This is an alert system and doesn't have to be perfect. This is the difference between a sensor in a self-driving car and a sensor for something like Shotspotter. If a self-driving car sensor has a 1% fail rate, then it is useless and would cause crashes and death. It couldn't be used. But if shotspotter is 1% inaccurate, then it just sends police to a street corner where there is actually just road construction or a volleyball popped. The consequences are pretty low to nil. Many people might not know this all calls have priorities in a policing system, they are not treated equal. So Shotspotter alerts are very low priority to officers. The same is true for home alarm systems. Home alarm systems trigger false alarms constantly. Police treat them as very low priority as a result. So if a 911 call comes in or an eyewitness reported shooting, or even a wreckless driver or suspected DUI, the police will treat that first. In fact if they are on the way to a shotspotter alert and encounter something else, they will stop for it. This is to say, that the false positives aren't as important as everyone makes them out to be. If a false positive happens, it means that a cop that's sitting on a random street corner gets moved to a street corner where the false alarm from Shotspotter fired. There's not really any harm being done here.
    - lifeformed 3y ago
      > The consequences are pretty low to nil. Having American cops rush to your door thinking violence is happening is not inconsequential. Just a few days ago they shot at a kid who was playing with fireworks, due to a false positive. Also, see swatting and its fatal consequences.
      - Jcowell 3y ago
        Exactly this. When it comes to American Police the consequences are not deterministically nil
      - astrea 3y ago
        As much as I hate to participate in political discussions, I have to agree here. No US cop would ever respond to gunshots in a casual manner. Think about Swatting.
- photochemsyn 3y ago
  Sound classification under fairly well-controlled conditions could be very different from a real world streetcorner situation, where sound can bounce off surfaces and generate different signals depending on direction and distance of origin relative to the collecting microphone. High-quality omni-directional microphones can be expensive and I imagine there would be theft concerns if they used really good ones.
  - hcfman 3y ago
    I recommend primo EM272 microphone capsules for use with https://github.com/hcfman/sbts-aru https://github.com/hcfman/sbts-aru. They are high quality, very sensitive with high signal to noise ratio, lauded for nature recording use cases. They can be bought assembled for around 65 euros in the Netherlands. However these capsules are often found in much more expensive equipment.

by loteck 3y ago

Aurornis 3y ago

> This system detects door slams and popped volleyballs just as well as it detects gun fire (which is to say, imperfectly on all counts). Sound classification moved far beyond what you’re claiming years ago. If you set the threshold at “imperfectly” then no system will ever meet your bar, because perfect is an unreasonable threshold. However, the claim that we’re unable to differentiate between gunshots and car doors is extremely incorrect.

loteck 3y ago
Shotspotter falsely classifies popped volleyball as gunshot: https://www.wtol.com/article/news/local/false-shotspotter-alert-in-east-toledo-tuesday/512-75fb9bb6-b9cf-49dd-889e-d31782ed9967 https://www.wtol.com/article/news/local/false-shotspotter-al... Slamming doors: https://www.axios.com/2022/04/07/campaign-zero-against-shotspotter-crime https://www.axios.com/2022/04/07/campaign-zero-against-shots... This list can go on. Jackhammer, nail gun, normal hammers. https://voiceofsandiego.org/2020/09/22/shotspotter-sensors-send-sdpd-officers-to-false-alarms-more-often-than-advertised/ https://voiceofsandiego.org/2020/09/22/shotspotter-sensors-s...
- jacurtis 3y ago
  Yes there are false positives. This is an alert system and doesn't have to be perfect. This is the difference between a sensor in a self-driving car and a sensor for something like Shotspotter. If a self-driving car sensor has a 1% fail rate, then it is useless and would cause crashes and death. It couldn't be used. But if shotspotter is 1% inaccurate, then it just sends police to a street corner where there is actually just road construction or a volleyball popped. The consequences are pretty low to nil. Many people might not know this all calls have priorities in a policing system, they are not treated equal. So Shotspotter alerts are very low priority to officers. The same is true for home alarm systems. Home alarm systems trigger false alarms constantly. Police treat them as very low priority as a result. So if a 911 call comes in or an eyewitness reported shooting, or even a wreckless driver or suspected DUI, the police will treat that first. In fact if they are on the way to a shotspotter alert and encounter something else, they will stop for it. This is to say, that the false positives aren't as important as everyone makes them out to be. If a false positive happens, it means that a cop that's sitting on a random street corner gets moved to a street corner where the false alarm from Shotspotter fired. There's not really any harm being done here.
  - lifeformed 3y ago
    > The consequences are pretty low to nil. Having American cops rush to your door thinking violence is happening is not inconsequential. Just a few days ago they shot at a kid who was playing with fireworks, due to a false positive. Also, see swatting and its fatal consequences.
    - Jcowell 3y ago
      Exactly this. When it comes to American Police the consequences are not deterministically nil
    - astrea 3y ago
      As much as I hate to participate in political discussions, I have to agree here. No US cop would ever respond to gunshots in a casual manner. Think about Swatting.
photochemsyn 3y ago
Sound classification under fairly well-controlled conditions could be very different from a real world streetcorner situation, where sound can bounce off surfaces and generate different signals depending on direction and distance of origin relative to the collecting microphone. High-quality omni-directional microphones can be expensive and I imagine there would be theft concerns if they used really good ones.
- hcfman 3y ago
  I recommend primo EM272 microphone capsules for use with https://github.com/hcfman/sbts-aru https://github.com/hcfman/sbts-aru. They are high quality, very sensitive with high signal to noise ratio, lauded for nature recording use cases. They can be bought assembled for around 65 euros in the Netherlands. However these capsules are often found in much more expensive equipment.