Non retroreflective number plates

[powium]

It has come to my attention that all Australian and most European (most likely US as well) number plates are constructed of a retroreflective base, usually in white color, and non retroreflective lettering. I think the way they accomplish this is by embedding tiny glass spheres in the paint.

This makes it very easy to take photos of number plates from long distances. Also, when you're driving at night, people driving behind you can easily identify your number plate because it's being lit up by their headlights.

One of the reasons they make number plates retroreflective is because of speed cameras, a major annoyance for drivers in Australia. Some of the newer cameras are very devious, using an infrared camera/flash so you don't know you've been caught. These number plates work magically for the IR flash, reflecting the flash to the source (the camera) and providing a huge level of contrast between the background and the lettering.

If you've got some spare time, take a photo of your car at night with a flash and you'll see what I mean.

My theory is that if you paint over your number plate with a matte paint, you'll eliminate it's retroreflective properties, reducing chances of your number plate being photographed by a camera/flash setup. It will be calibrated for retroreflective plates, and when it flashes your plate and gets a fraction of the expected level of light, the picture will be illegible.

I've applied this theory to my own number plates, painting the background matte black, and the numbers white (not reflective though). By day, this looks just like a regular number plate (it is possible to order this color scheme legally from the issuing authority, they just make it reflective) - but at night it is very difficult to photograph.

I apologise if this is too far off topic, but I thought it might be of interest to the scientifically literate. Any thoughts/feedback most welcome.

[monkeyboy]

Where I'm from it's illegal. A friend did it to his plates, as part of a ground up restoration of his hot rod, not criminal intent at all. Made it look real nice, spent quite a bit of effort in tracking down the right colors. A cop was behind him & noticed the plate, while equipped with the requisite bulb, did not reflect correctly. They almost impounded the car. It's almost on a par with counter fitting money. I think the ticket was around $500.

[Bugger]

How about varnishing your number plates with a matte polyurethane or epoxy varnish? That should greatly reduce their reflectance.

[Jacks Complete]

There are several issues with this. If we coat the plate with something easily visible, you'll get caught. In the UK there are several firms making plates that are of dubious legality that don't reflect. However, using one is an offence. Plate covers are illegal here, too. As for making it not reflect so it is too dark, try it with a digital camera at night, then turn the brightness and contrast up in Photoshop, and odds are you will see the details easily enough.

A clever way around this it to make the entire plate reflect, black as well. Doing this means that cops can't even lighten the image to get the details, because all they get is a bright white square, and, when they shine a light on it at night, it still works and looks normal at a glance, or if they are following you. There are a number of commercially available products to do this in the UK.

Of course, it's fairly moot now here, because there is a trend towards using passive detection from regular video camera systems, combined with OCR. If you can read it, they can. Of course, at night, you never see them, so odds are it doesn't work after dark! But since it's got nothing to do with road safety, and is all about the income, they don't seem to bother solving that issue.

[tmp]

It's illegal to use a plate cover in Maryland. A friend, in his late 70s, had
called the local pork to report vandalism on his car. Barney Fife took down
the report(useless DUMBASS !) and then proceeded to harass my friend for
having a cover over his license plate. At least the pig was honest about it
when he told my friend that it interferes with red-light cameras. Now they're
talking about the speed limit cameras for Baltimore. Money-grubbing
politiicians know no limits to stealing taxpayers' hard-earned income !

My personal view is that I want something to DESTROY the camera at a
considerable distance ! I've been mulling over a few non-noisy methods ! :D

[grayssk]

Of course, it's fairly moot now here, because there is a trend towards using passive detection from regular video camera systems, combined with OCR. If you can read it, they can. Of course, at night, you never see them, so odds are it doesn't work after dark! But since it's got nothing to do with road safety, and is all about the income, they don't seem to bother solving that issue.

Couldn't you defeat passive cameras with some ultra-bright IR LEDs? Just mount them in a ring around the plate, and wire them through the battery, the way idiots wire ground lighting. If you pump out enough light, it should overwhelm the CCD in the camera, which will pick up the IR, but will be completely invisible to all pigs giving your car a once-over.

[monkeyboy]

My personal view is that I want something to DESTROY the camera at a
considerable distance ! I've been mulling over a few non-noisy methods ! :D

You might find these helpful:
How to ZAP a Camera:
Using Lasers to Temporarily Neutralize Camera Sensors
http://www.naimark.net/projects/zap/howto.html

Researchers develop prototype system to thwart unwanted video and still photography
http://architectures.danlockton.co.uk/2006/06/19/researchers-develop-prototype-system-to-thwart-unwanted-video-and-still-photography/

My infrared-veil
http://forums.makezine.com/comments.php?DiscussionID=89&Focus=338#Comment_338

Sniping the security
http://www.c-h-a-o-s.com/2007/08/11/sniping-the-security/

Laser Flashlight Hack
http://www.instructables.com/id/EWM4YR2F4WY1LQ2/?ALLSTEPS

[nbk2000]

Setting the IR LED's to pulse in a random pattern of varying brightnesses would play hell with the cameras, as it'd be trying to adjust it's gain to deal with the last frame, which is no longer the same as the current frame, etc.

[Jacks Complete]

I actually came up with this a few days ago whilst brain-storming. Another one I saw somewhere was the "FlasHat" - a simple circuit responds to the camera flash by firing another flash back at the camera, or, for preventing photos of celebs at the wrong time, the flash fires downwards, lighting the face, especially the nose and cheekbones and upper lip, whilst not having any effect on the wearers eyes. I'm not having any luck with finding it online, though. There are dozens of false hits, and several things like it, though, such as at the bottom of this page http://www.we-make-money-not-art.com/archives/009552.php
and this page http://www.textually.org/picturephoning/archives/2004/11/006109.htm has some fairly random, though interesting ideas, though who thinks any paparazzi will turn on the setting that allows the privacy badge to protect its wearer?

Since the shutter time on the camera is going to be at least a millisecond, it is actually fairly easy to react to it and counterattack at the speed of light.

Personally, I'd combine several systems, so that it fires an IR flash back at the flashgun in the static camera, and a white light flash downwards at the numberplate. This would effectively jam anything at all, since the IR will be invisible to the guy behind, and the flash heading downwards would be covered by the static camera's flash. I would also use a coating that claimed to reflect more light at the camera, but I would apply it partially.

To see why partial use is your friend, write down something like a license number on a bit of paper. Now, try to erase it with the same pen without making holes. It takes a lot of work, and you can probably still, just about, work out what was written. Now, do it again, but write another letter over the letters - try changing an H into an N. One stroke, and it is already impossible to tell what the original was. Do this with your plate, and outline one letter so it is entirely impossible, under flash, to determine the original letter. Do this to a few digits, then wipe the entire mass of one of them, and two others. (Use your head in your choices) Now, your plate is impossible to "make" from any one photo, even if they play with the contrast, even if the coating is wearing off a little, etc. and also it is a passive backup for when your flash fails to fire because a spider made its home in the sensor!

You would need twin power systems, since the cameras take two photos (in the UK at least) 0.25 seconds apart, and your speed is worked out from the distance moved in that time from the (extra) white lines on the road.

There are two other systems in use, too. They use no radar, or laser, as my detectors have never yet tripped as I've driven through them. One looks different to a regular GATSO, but is clearly recognisable, and has just 3 lines painted on the road.

The other, and the most serious one to find out about, is the "Talivan" which is a mobile speed trap system that the police hide in the back of a van on the side of the road. It generally sees you before you see it. As far as I know, it uses video evidence, and is totally passive. However, I've never worked out what it keys off. It might be twin rangefinding cameras, but that's pure conjecture.

[nbk2000]

I think the one with the 3 lines is a camera that detects when a moving car obscures the lines, and calculates the speed based on that, using optical motion sensing to turn on.

I've seen myself a lot of inks that are transparent in IR, but otherwise visible to the naked eye.

You could have two layers for your plate, one the actual plate number (visible to the eye), and the other a transparent layer of IR opaque ink, that would do the H/N obscure like JC described. :)

[megalomania]

There is an aerosol spray for license plates that can block out the cameras. One product is available from phantomplate.com. I found this youtoob video of a Fox News broadcast where they had the police test these products:
http://www.youtube.com/watch?v=-_e2BC_kXis

It looks like the spray worked the best, beating the plastic plate covers. The spray causes a high gloss finish that causes the license plate portion of a photograph to be overexposed when a camera flash is used. This is the opposite of the principle powium suggested. The spray actually increases the amount of light bouncing back to the camera

I am surprised the police let the journalists film them testing these products. Technically, according to the report, these things are not illegal (yet).

Now all I need is one of those traffic light changers firetrucks use :)

The spray still does not address light reflectivity for reading by human eyes. The spray might make seeing the plate even easier at long distances if it even more reflective. You can always put your plate in the back window. I don’t know how legal that is, but it will be away from the direct beam of headlights, and thus harder to read.

[monkeyboy]

On a semi-related note:

A while back I ran across a little package that you strap to the bottom of your motor cycle, to trigger inductive light sensors. It appears to just be a small electro-magnet, although some are just a couple rare earth magnets.

So that got me thinking...

Are the red light cameras hooked in to the inductive sensor?
If they are, couldn't you wind a couple coils & glue them to some plywood. Then lay them across the corner of the sensor & fire it at the appropriate time to cause the camera to go off?

How many pictures of nothing do you think it would take for them to get the point?

Any suggestions on how to do this for speed cameras?

[Toggle]

Now all I need is one of those traffic light changers firetrucks use :)

Well if you really want one here's the plans for building your own for under $20 as opposed to trying to buy one (if you can) for $340.

The "DIrtY MIRT"
http://www.i-hacked.com/content/view/176/44/

What's one more FEDERAL Offense, right ? :rolleyes:

[Mr Science]

^ I have a feeling the one you posted Toggle would work better, but here are several traffic light-themed videos I discovered.

http://www.metacafe.com/watch/496319/change_traffic_lights_with_a_universal_remote/
^Turning a TV remote into a MIRT

http://video.google.com/videoplay?docid=5307919148544017291
^Doing the same thing, but by pressing the walk-button in a special combination.

And I learned at one point these actually were LEGAL for the general public to have, but they became illegal in most states in 2005, if not all.

EDIT- http://www.themirt.com/markets.html
And take a look at this website, might show a few people to start being friends with. ;)

2ND EDIT- What would even be nice is for someone to get one real one, and do an autopsy of it on video.

3RD EDIT (Seriously, I am done)- Found a website that DOES sell these.
http://www.skyoptics.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=030

[Toggle]

The Universal TV remote thing is a joke. Cop cars do not emit a '911 code' to turn the lights to green. It's simply a 14Hz infrared flasher. Even if a TV remote could output the right signal, that one IR LED on the remote is going to be too feeble to effect the MIRT.

I fell for the traffic light code too. I actually tried it years ago. This bit of "info" has been around for at least a decade.
But at least I'm not the only sucker to bite.

Is there a secret code to control traffic lights?
http://www.wisebread.com/is-there-a-secret-code-to-control-traffic-lights

As far as I know it's still legal under Federal law to build and have a MIRT. Selling or using one is illegal.

[Man Down Under]

Illinois installing IR license plate reading cameras in all interstate rest stops, connected to automated databases.


http://ftp.extremecctv.com/marketing/Extreme_Documents/PR%20-%20Illinois%20Interstate%20Highway%20get%20REG%20L PR_v2.pdf


“We are proud to be a part of an on-going effort of securing
North America and excited to see our award-winning REG™
be a part of a statewide initiative to protect the citizens of
Illinois,” said Jack Gin, CEO and President of Extreme
CCTV. “ We think our REG™ License Plate Reader should
be installed throughout the highways of the USA for
integration with powerful and effective programs such as
‘Amber Alert’. Most crimes involve vehicles so an
automated computer driven vehicle identification system
would be of enormous aid to law enforcement agencies.
Recent highly-publicized child abductions in the USA have
underscored the need for the kind of Automatic License Plate
Reading (ALPR) that has quickly become popular for pro-active
policing in the United Kingdom”.

'For the Children' justifies anything.