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I have seen the question raised in a previous thread about whether SPECS cameras can read number plates at night and the answer was yes - by infra red. I was intrigued by the number of cars passing me last night in the (in)famous M1 roadworks between Luton and the M25 - I was doing a constant 50 but lost count of the cars (and lorries) passing me, and not just creeping past at 51 but hurtling past. Are they all anticipating SPECS doesn't work at night or will they be receiving brown envelopes?
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I have been past some of these yellow-poled SPECS on motorways at around 20mph over the hideously-low limit, and I suspect they are fake, set to 70mph for legal reasons or just CCTV, as I have never had tickets.
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I raised this point some time ago. I have a strong suspicion that these cameras cannot operate at the speeds required and in the presence of stray visible light, water spray etc. at night. Having seen some of the military technology which can do this, my thoughts are that the units on the gantries are not up to this job. Of course, it suits Whitehall admirably for us to believe they operate under all conditions.
This Forum can easily prove or disprove this. Could anyone caught by one of these cameras in darkness please post here?
659.
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Those on A1 at wetherby 50 mph appear to only have 1 camera although there are 2 lanes.
I bigger central (camera?) box and 2 smaller adjacent sensors??
do they only scan 1 lane.
Have seen previous discussion re changing lanes as it is believed to only compute over 1 lane.
can any body confirm???
THANKS
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This Forum can easily prove or disprove this. Could anyone caught by one of these cameras in darkness please post here?
In fact, come to think of it, afaik I don't know anyone who as been snapped by a SPECS camera at all, never mind whether it be light or dark.
The ones currently on the M69 roadworks don't appear to be pointing at ANY lane, just vaguely pointing towards the ground.
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I doubt that an infra red camera can read a number plate. Correct me if I'm wrong but AFAIK Infra red cameras rely on differences in heat signatures, how is the camera going to see the numbers if they are behind a perspex sheet, the surface temperature of the number plate is going to be constant surely.
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I doubt that an infra red camera can read a number plate. Correct me if I'm wrong but AFAIK Infra red cameras rely on differences in heat signatures
Here is the correction. Infra red cameras use a different portion of the light spectrum to "see" Less white light is required in this application.
surface temperature of the number plate is going to be constant surely.
You are thinking thermal imaging.
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Here is the correction. Infra red cameras use a different portion of the light spectrum to "see" Less white light is required in this application. You are thinking thermal imaging.
I stand corrected ;0)
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>> >> You are thinking thermal imaging.
An example of active infra-red "night vision": snipurl.com/210yh [en_wikipedia_org] .
This system is clearer than military ones, but not used by military as the infra red emitters are easily visible by the enemy. Ive no idea whether the Specs images have the same clarity as this.
;o)
Edited by Rich 9-3 on 05/03/2008 at 13:52
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easily visible by the enemy.
Should obviously read "visible to"!
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kith
Emissivity factors are the big problem with remote temperature measurement. Objects at the same temperature but with different emissivity show up clearly on infra-red. believe me, I've tried it. This why infra red cameras would be able to read number plates.
Same temperature across the plate yes, but the black letters will have greater emissivity than the surrounding white, so they would show up clearly and could be 'read' by suitably sensitive equipment.
JS
Edited by John S on 06/03/2008 at 19:13
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In fact come to think of it afaik I don't know anyone who as been snapped by a SPECS camera at all never mind whether it be light or dark.
Yeah, by the ones on the way into Nottingham, it was a Friday Evening last summer. Still fairly light outside if I remeber correctly.
Lee
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The ones on the M42 work.
We've got infra-red fitted to the ANPR in our cars. They read number plates without problem at night.
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Infra red ANPR from a car is relatively easy. Distances are closer, data capture time is far longer with no angle correction factors needing to be built into the image procesing software.
I'm still very sceptical as to whether "they" have actually achieved this reliably from a gantry camera. Night time bookings - please record here.
659.
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Data capture time is longer? It's a fraction of a second and the camera's are a lot smaller.
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MLC
Can you see the red glow from the infra red light which is transmitted from the Police vehicle?
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Let me get this right then, an infra red camera such as ANPR transmits infra red light then picks up the picture from the reflected light that it has transmitted ?
A bit like shining a toch on an object in the visible light spectrum.
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Let me get this right then an infra red camera such as ANPR transmits infra red light then picks up the picture from the reflected light that it has transmitted ?
AFAIK infra red is only just outside the visible spectrum. So far as the camera is conerned the IR is as good as a floodlight albeit with litle colour differentiation.
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" bit like shining a toch on an object in the visible light spectrum"
But you'd notice a high powered torch wouldn't you. So the discreet infra-red light which you cannot see and therefore cannot affect night vision etc. is better.
Not a problem for any of us anyway. Don't speed and no risk with any speed camera technologies or the good old traffic officer. So nothing to worry about.
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\"Can you see the red glow from the infra red light which is transmitted from the Police vehicle?\"
Fullchat...No! It\'s very discrete.
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"on the way into Nottingham"
No help re the night time discussion, but son was done by a specs camera a year ago going out of Nottingham - A610 Mansfield Rd I think - daylight though - 34 in 30 limit.
Thing I wonder about while driving cautiously at 50 through the M1 ones is whether they can record EVERY car going through when there is a constant stream of 2/3 lanes of traffic. Can they?
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Yep. I can park on the hard shoulder and my ANPR merrily pings away as each and every car goes past.
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mlc,
Thanks - that's really cheered me up!
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