Car numberplate not readable when infra-red comes on!

[AlienDroid 0]

I've searched but not found anything on this problem but it must have been covered before on this site.

 

When in low light and darkness once my cams infra-red LED's come on the background of the numberplate or licence-plate reflects back and I can no longer read the plates! Can't see a single letter!

 

I've read about specific cameras for reading plates, so do I need to buy a cam suited for that job or can I add a filter to reduce reflection using a standard cam?

[survtech 0]

The problem is probably angles. If your IR light reflects straight back into the camera, it will overload the images. You need to locate the camera and light source so that the light reflects away from the camera.

[AlienDroid 0]

The problem is probably angles. If your IR light reflects straight back into the camera, it will overload the images. You need to locate the camera and light source so that the light reflects away from the camera.

Thanx for the reply survtech.

 

I'm very restricted on where I can install the cams so changing their position is impossible if I'm to maintain best coverage. The 2 in question just can't go anywhere else due to the design structure.

 

I'm using dome cams BTW, so built in LED's.

Strange thing is they're installed at about 7ft and on garage so cars pass at an angle so I didn't expect to get so much light reflecting back into the cams with this height and angle of approach!

 

I'm using 2 different cams from different makers but get almost the same result from both. The funny thing is even in total darkness headlights can sometimes turn the infra-red off and I can just about make out the numberplate! But I can't reply on that!

 

Even when the car comes closer and the angle increases it still reflects back. Only when at an impossible angle right next to cam the plate starts to show but then not possible to read the plate.

 

Would it work if I filter one of the cams LED's so it can only pick up plates but then no good for anything else?

[Securame 0]

Pics of what the cameras see during day and night would help.

 

You could also try disabling the leds on the camera, and installing IR a little bit away from the camera on a place where the reflection is not be a problem.

[AlienDroid 0]

Pics of what the cameras see during day and night would help.

 

You could also try disabling the leds on the camera, and installing IR a little bit away from the camera on a place where the reflection is not be a problem.

Thanx for reply MindTwist

The attached pic is just on the time the infra red comes on, last month anyway. If it didn't come on it would be possible to make out the plate (just about) but gives you an idea how bad the problem is if it can cause a problem before it even gets dark!

 

I really only have the width of the garage to install anything so not really an option for me to install another IR light.

maybe I could try and install an IR pointing straight down?

[survtech 0]

AlienDroid,

 

Your angle doesn't appear to be the problem. It might be an AGC problem with the camera. Try turning AGC "Off" or at least adjust its level way down in the camera's menu. Also try closing the iris and adjusting the shutter settings.

 

That's a pretty severe angle to see plates.

[AlienDroid 0]

AlienDroid,

 

Your angle doesn't appear to be the problem. It might be an AGC problem with the camera. Try turning AGC "Off" or at least adjust its level way down in the camera's menu. Also try closing the iris and adjusting the shutter settings.

 

That's a pretty severe angle to see plates.

Hi survtech

 

I took that snapshot to just show how bad the problem is when IR is on even at that silly angle! I can read the plates around 15 to 20ft away in good light conditions but not when the IR comes on!

 

I have 2 cams on my garage but neither have on-board menus as far as I know, one is cheap as chips, the one that took above image is a 600TVL which is the better one.

 

I do have cam settings menu for each channel on the DVR but I'll check tomorrow if it has AGC, I don't think so

I did try playing with the settings a while back but didn't help.

[shockwave199 0]

You want to do something specialized with cameras that cannot do it. It's all about the camera. It's probably not practical for you, but I find ptz's can be effective for plates at night. The full control of them helps, as well as being able to cover other needs and areas when plates are not needed. I use two different ptz's, one at home and one at work. They both deliver plates because of the full control over the camera when needed. Also keep in mind that grabbing plates from cars on the move adds an even bigger hurdle too.

 

 

 

 

This is an excellent shot I got with my home ptz with adjustable IR at over 100' away-

[AlienDroid 0]

Hi shockwave199

 

That's an impressive set of pics. I'm trying to keep the cams low profile as they're not very high so having a PTZ will only make it an easy target most likely. The cars come by pretty close and speed may be a problem anyway.

 

Could send me the cam speck or make you're using? PM me if you don't want to put that up on a post! I think you're right, I just don't have the best cam for the job.

I'll be checking today if I can make any adjustment a previous poster suggested but I don't think my cams have a built in menu etc.

Note. I did see a clip online a while of a cam that can be made to capture plates by adjusting its settings! My DVR is only 960H so maybe not sharp enough, plus with PAL 25fps and not 30fps under NTSC!

 

If you could also send me details of the cam you got that amazing shot of 100ft away with adjustable IR I would appreciate it?

 

I'm pretty sure I can filter the IR light down with sticking on my home made filters but think I need a better cam, when I stuck on some filter before I got IR reflection back into the lens which gave crap results.

[tomcctv 189]

Hi . Alien.

With a UK plate you will not get image using standard IR.

But with the distance in your image I would look at covering up your IR. and just see what image you get from the plate without

[AlienDroid 0]

Hi . Alien.

With a UK plate you will not get image using standard IR.

But with the distance in your image I would look at covering up your IR. and just see what image you get from the plate without

Hi tomcctv

 

I did mean to ask a question you've just reminded me of..

Is there a difference to the reflective background on plates when comparing UK, US and CA etc etc?

So is there a special IR lights specific for recording plates?

Or does this just come down to getting the right cam for the job?

 

I did make my own IR filters up but it didn't work too well. Although they did help a bit with reading plates they also caused the IR LED's to reflect light back into the lens!

 

What I originally wanted was no visible light from the LED, I didn't realise that most cams were using 950nm, so was thinking about a small project and see what difference swapping out the 950's for 850nm LED's would make!

Probably not worth the bother but have you or anyone on the forum tried anything like this?

 

In answer to your question about covering the LED's. I need the cams also to watch out for fly tippers about 90ft either side of my garage, night time at the moment that gives me about 25ft

So if I cover the LED's that gives me a problem, but yes it will work better if cars are very close as long as they keep there lights on!!

So I'm thinking now should I install a specific night numberplate cam that will just do that job and not be much good at night to see anything else?

 

PS. Had a recording yesterday of a car that when it had it brake lights on the IR's turned off and I could see the plate. When brake light went off the IR's came back on and couldn't see the plate at all!

[tomcctv 189]

Hi yes between Uk and US plates are very different. Uk are reflective and readable for upto 100m.

 

 

It might be worth you using two cameras your current one for the fly tipping and a black white for plates.

 

You can run 4 cameras from the one coax if installing another cable is a problem.

 

 

In the uk you should not be funding this yourself there is money available

[shockwave199 0]

One ptz I use at work is a dahua and the other- the one that grabbed the last shot at my home, is a no name brand from ebay. But it has been doing well for over a year now. But as you mention, a ptz isn't right for your situation. Good luck to you.

[AlienDroid 0]

Hi yes between Uk and US plates are very different. Uk are reflective and readable for upto 100m.

 

 

It might be worth you using two cameras your current one for the fly tipping and a black white for plates.

 

You can run 4 cameras from the one coax if installing another cable is a problem.

 

 

In the uk you should not be funding this yourself there is money available

Hi tomcctv

I think I'll take your advice on installing a black & white cam for plates only and one with an on screen menu this time so can tweak the settings.

 

So the UK reflective plates don't seem to work great with IR's. Maybe that's why most speed cams have to use flash to light the whole street up like the sun just came up then lol

 

If as you suggest I can save laying a new cable that would be great!

I dug a small trench about 60ft and put 2 cables inside for the current cams and pipe for protection, so laying a 3rd cable would be a lot of extra work as I almost used all of the 40m run after spending time hiding it and not taking the direct route.

I have no idea how I can run 4 cams off one cable so if you can save me some searching on how to do that I would appreciate it?

 

I'm not sure about the funding for cctv, I know we pay the government in taxes to watch us but not sure about the other way round?

[AlienDroid 0]

One ptz I use at work is a dahua and the other- the one that grabbed the last shot at my home, is a no name brand from ebay. But it has been doing well for over a year now. But as you mention, a ptz isn't right for your situation. Good luck to you.

Hi shockwave199

Thanx I'll check that cam out and have something to compare on the spec when searching for another cam.

 

Cheers everyone for the info and replies " title="Applause" />