RE: Can they catch you using sound?
Discussion
chrisjl said:Doppler shifts have potential but how will they cope in real world real time with gear changes and so many signals coming in some of which will cause beats etc. Seems like too much trouble when there are already better solutions at work now...
It's not about what gear you're in, or what circumference your tyres are. It's about the difference in the perceived sound as you go from approaching the vicinity of the microphone to departing it.
[quote=turboblokeSeems like too much trouble when there are already better solutions at work now...[/quote]
Thats tony and mates - first decimate (possibly) the best traffic police in the world for some dodgy bit of gear , then try some more flannel.
Be interesting to see what happens to these mikes when a chavmobile goes past with the chavsound (and base ) making houses shake.
Or when a cyclist goes past after a nasty curry.
>> Edited by oldie on Tuesday 25th April 12:30
Thats tony and mates - first decimate (possibly) the best traffic police in the world for some dodgy bit of gear , then try some more flannel.
Be interesting to see what happens to these mikes when a chavmobile goes past with the chavsound (and base ) making houses shake.
Or when a cyclist goes past after a nasty curry.
>> Edited by oldie on Tuesday 25th April 12:30
What a load of shit! So its acurate within a few percent 97 percent of the time! So it knows about my engine does it? Does it know i've changed the exhaust and air box which changes the sound? What if i've put different sized wheels on and changed the gearing? Or just changed the final drive?
eein said:Yes they do. SPECS emit pulsed IR for VRM illumination.
Averaging camera systems do not emit anything either ........
How so would this system differentiate between different cars, or even the same model cars? What happens when there are two cars, one overtaking the other? What about corroborating evidence? What about vehicle/driver ID? - this idea has more holes than the shadow mask in my CRT monitor.
Presumably theres two ways of doing this -
1) If you know how many cylinders and what cycle its running (ie. 2 stroke/4 stroke) you can in theory determine the engine speed from the noise it makes. There are a few small problems(!) like knowing what the engine configuration is, what gear the car is in, detecting gear changes during the speed trap area etc etc etc etc
2) The other way of doing it is with the Doppler effect, but if the car was accelerating or decelerating the frequency of the sound source would change and it would screw up the Doppler. (I think). Also strikes me as a very complicated way of doing it.
There is of course a simple 'stealth' way of doing it, but wouldn't want to give fuhrer Blair and his chums any ideas!!
1) If you know how many cylinders and what cycle its running (ie. 2 stroke/4 stroke) you can in theory determine the engine speed from the noise it makes. There are a few small problems(!) like knowing what the engine configuration is, what gear the car is in, detecting gear changes during the speed trap area etc etc etc etc
2) The other way of doing it is with the Doppler effect, but if the car was accelerating or decelerating the frequency of the sound source would change and it would screw up the Doppler. (I think). Also strikes me as a very complicated way of doing it.
There is of course a simple 'stealth' way of doing it, but wouldn't want to give fuhrer Blair and his chums any ideas!!
Chaps, just found this:
www.freshpatents.com/Truck-acoustic-data-analyzer-system-dt20060223ptan20060037400.php
>> Edited by smeggy on Tuesday 25th April 23:30
www.freshpatents.com/Truck-acoustic-data-analyzer-system-dt20060223ptan20060037400.php
>> Edited by smeggy on Tuesday 25th April 23:30
Pah, once Road Angel have a database, then they are flawed again.
They can't really be hidden too well either, otherwise you can easily dismantle/damage them. Wires? Where? They won't be obscure even if they used them.
Clutch in as you approach?
It assumes everything from the engine speed, if you approach in 1st and pass in 6th it'll expect you are going 400mph! Or if you pass it accelerating it won't know if your just slipping the clutch or actually transmitting torque to the wheels!
Maybe good as a "guide", but you couldn't use it for prosecution without the good old time delay imagery, so whats the point?
Stupid system, probably only works if the car is going a constant speed in the same gear. Real world tests my bottom!
Dave
They can't really be hidden too well either, otherwise you can easily dismantle/damage them. Wires? Where? They won't be obscure even if they used them.
Clutch in as you approach?
It assumes everything from the engine speed, if you approach in 1st and pass in 6th it'll expect you are going 400mph! Or if you pass it accelerating it won't know if your just slipping the clutch or actually transmitting torque to the wheels!
Maybe good as a "guide", but you couldn't use it for prosecution without the good old time delay imagery, so whats the point?
Stupid system, probably only works if the car is going a constant speed in the same gear. Real world tests my bottom!
Dave
Einion Yrth said:
I thought they used this to detect submarines and called it SONAR. It's a 70+-year-old technology.
Sonar is active, this is passive.
From [url]http://en.wikipedia.org/wiki/SONAR[/url]
"Active sonar creates a pulse of sound, often called a "ping", and then listens for reflections of the pulse."
"Passive sonar listens without transmitting. It is usually employed in military settings, although it is occasionally used in science applications.......Another use of the passive sonar is to determine the target's trajectory. This process is called Target Motion Analysis (TMA), and the resultant "solution" is the target's range, course, and speed."
Why dont the Americans study something useful instead of trying to develop speed detection devices to sell at excessive prices to the British Government, it is not as though the Americans will use them.
Shaft the Driver all the time!!!!!!!
Why dont we start suing pedestrians for damage to our cars if they are run over in the road!!!!!!
Lets alienate the pedestrian and start charging them the walk on the pavements, and have scameras up to see if they are exceeding the walking speed limit dropping litter etc etc.
(sorry this is getting silly now isn't it, then again so are all these anti-speed devices)
Shaft the Driver all the time!!!!!!!
Why dont we start suing pedestrians for damage to our cars if they are run over in the road!!!!!!
Lets alienate the pedestrian and start charging them the walk on the pavements, and have scameras up to see if they are exceeding the walking speed limit dropping litter etc etc. (sorry this is getting silly now isn't it, then again so are all these anti-speed devices)
you could measure speed by the change in pitch between the cound coming toward you and the sound going away as the car passes. Not sure what the maths are but I think that the actual sound of the car is immaterial, it's how the sound changes that's the important bit. Thing is, if as the point of passing the device you put your foot on the clutch, the pitch would drop dramatically as the engine slows, giving a big pitch change and therefore a big speed reading. The electronic companies will come up with anything to sell won't they!. And so far, they've done rather well out of it when you think!
You have to love this site. A report about a technology without any actual statement that the uk are going to deploy it as speed ticketing system and you guys are in anti-establishment mode within a couple of hours. Has anyone actually read the original New Scientist article?
I can think of a few uses for this technology without considering speed enforcement. In fact it is highly unlikely to be used for speed enforcement for the reasons some of yous have mentioned.
I can think of a few uses for this technology without considering speed enforcement. In fact it is highly unlikely to be used for speed enforcement for the reasons some of yous have mentioned.
I think this system would work rather well indeed. My guess is it uses a sophisticated combination of doppler effect and frequency measurement to determine the speed of a car, and the big plus point of this kind measurement: It will probably be able to process a bunch of cars simulataneously (like when installed on a motorway bridge or something), when used in combination with a low frequency video camera to identify the number plates and the type of car, and to provide some visual estimation of the traffic situation. This is of course highly interesting to governmental authorities who never get tired of taking money from motorists for even the most irrelevant of causes. And additionally, it will help to install new laws limiting the use of aftermarket exhaust systems, as those will of course make it harder for the system to determine accurately wether it was the Golf, the Peugeot or the Ford that endangered world peace by going 125km/h in the 120 zone.
Very nice system in fact, for people who hate cars in general, and noisy cars in particular.
Chris
>> Edited by ChrisD on Tuesday 25th April 20:32
Very nice system in fact, for people who hate cars in general, and noisy cars in particular.
Chris
>> Edited by ChrisD on Tuesday 25th April 20:32
summit7 said:
Yet more money being spent in the name of road safety that will not make a jot of difference to the death stats on our roads. Why don't they spend the money on a) DRIVER EDUCATION, b) CARDINGTON TRAINED TRAFFIC POLICE. rant over now - Summit7
As a matter on interest, what is Cardington Trined Traffic Police, thats a new one on me.
Maybe the technology could be altered to pick up the sound of breaking glass, fit them to every house, link it via satelite to the local police station, and hey, they can ring you and tell you your house is being burgled, save them having to come out to investigate, you can do it yourself!.
Meanwhile over half the world is starving, buts lets spend zillions to catch those speeding motorists, so we can gather more money to make more gizmos to catch motorists, so we can gather more money etc etc etc.............
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