Surveillance Cameras Get Smarter

kog777 writes to mention that the IB Times is taking a look at where surveillance camera technology is headed. Soon researchers tell us that cameras will be available that not only record, but are able to interpret what they see. "The advancements have already been put to work. For example, cameras in Chicago and Washington can detect gunshots and alert police. Baltimore installed cameras that can play a recorded message and snap pictures of graffiti sprayers or illegal dumpers. In the commercial market, the gaming industry uses camera systems that can detect facial features, according to Bordes. Casinos use their vast banks of security cameras to hunt cheating gamblers who have been flagged before."

Comments

Gunshots

[Threni]

> For example, cameras in Chicago and Washington can detect gunshots and alert police

Can they tell the difference between gunshots and recordings of gunshots played back on people's mobile phones? I think we're about to find out!

Re:Gunshots

[celardore]

You may be aware that the UK is ahead of everyone else in terms of CCTV surveillance. This doesn't mean that the UK has a lower crime rate though, nor does it mean that they are on top of terrorism or gun crime. There has been a lot of publicity in the UK recently about gun crime, with a famous picture in the papers of Tory leader David Cameron with a youth behind him making some kind of gang sign related to guns.

Surveillance is not the answer, it doesn't make a difference if there are too many criminals to monitor. Gun laws (as Americans will say, right to bear arms etc) are not the answer. This has lead me to believe that there is no answer. We have to be politically correct remember. Don't discriminate against trolls, they're people too.

Doubt it.

[Kadin2048]

Most sound effects / recordings of gunshots aren't accurate representations of the sound (aka, air pressure waves) produced when a gun actually goes off. They're more of an artists' interpretation of what the human mind thinks that a gun sounds like, based on what we remember them sounding like after we've heard one.

Most speakers can't accurately reproduce a gunshot, because they can't move enough air at one time to create the pressure wave. They play something that's more of a "boom," when in reality a gunshot is a sharp "crack" (followed by reverberations / reflections from the room or surrounding objects). Not being able to play the initial 'crack' very well, they over-emphasize the reverberations.

A 'gunshot sensor' would probably be a microphone or microphone-like device that was purposely de-sensitized so that it only received particularly loud, sharp sounds. You might be able to fool it with something explosive (like dry ice and water in a soda bottle), or where there was a significant release of pressure (car backfire), but most sound-reproduction systems wouldn't cut it -- they don't move that much air at once. Even with things like backfiring and explosions, you could probably filter them out if you wanted to, because I doubt they're the same when you really look at the waveforms (I suspect that the high pressure escaping from the small aperture of a gun's muzzle makes a very distinct sound from a car backfiring through the 1-2" muffler), even though they sound the same to a person, because we're not good at discriminating very loud, sharp sounds.

OT: I wonder what a nearby lightning strike "sounds" like to a microphone with the capacity to accurately measure the maximum amplitude of the sound?

Re:Doubt it.

[feepness]

If you want a pistol shot, use a rifle. If you want a rifle shot, use a shotgun. If you want a shotgun blast, use a Howitzer.

Crap, I need a Howitzer recording... anyone got a spare atomic weapon?