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I moved my license plate camers from under an eave into it's own housing with heater/fan. It gives a better angle. Cars drive directly towards the camera instead of past it at a 20 degree angle) Critique welcome...

At those prices you have money left over to buy a can of spam.

What does this look like if the car has a smoked license plate cover? I've reviewed aprx 10 days worth of video... hundreds of vehicles not seen one yet. Also, we're catching plates coming AND going... we have front and rear plates in TX. Seen any printed plates? More seriously, what about temp tags and motorbike plates? Smaller writing.

Smoked plate covers are difficult to see through. At night with IR it's relatively good. During the day it's relatively good too. You have to watch out for that dusk/dawn twilight time where there's enough light to keep the IR off but not enough to keep a good shutter speed. The pro cameras should have that covered. This is bad enough with uncovered plates when you use a non-LPR camera to read plates. The smoked plate increased the amount of time that the plate is unviewable during the dusk/dawn hours. The smoked covers show up as darker, of course, so if your brightness/contrast etc are set to a good level for seeing regular plates then you may or may not see though smoked covers. This is one of the reasons I use multiple channels recording of the same image with the brightness/contrast set per-channel at the DVR. The three different settings give me more chances of hitting upon the right levels on at least one channel.

Most like that aren't DIYers though; they're gathering info to play the pros against each other and get bargain-basement quotes. Can you offer two quote levels? A simple quote with cam positions and generic specs is free, whereas a quote with specific hardware, lens settings and detail that took time to prepare would cost $100 (credited against the job if they go forward) I'll get competing quotes from contractors and I select based upon the rapport I develop with the contractor and the "vibe" I get from him or her, not he quote amount. Slimy sales approach is a deal-breaker. Down-to-earth normal guy who knows his stuff wins it every time. Having said that, I will NOT get a quote from a contractor with the intent to use that quote as a blueprint for a DIY install. That's like doing free consulting work...

What does this look like if the car has a smoked license plate cover?

I'm definitely in the D category. I do it because I enjoy the technical challenge of getting different types of shots. My stuff is not critical and if I screw something up then so be it. I'm under no deadline.

What do you want the cameras to do?

If your camera has the IRs built in then it will refect rain/snow etc. How about using a seperate IR illuminator mounted sever feet away from the camera but pointing at the same place? This will also help stop objects close to the camera from being washed out.

Couldn't find a camera that stated it had eclipse and negative. Also, the primary aim was to deal with the low contrast between the lettering and abckground on some plates. That is what I'm trying to fix with the negative feature. The headlights are a secondary concern and my current setup deal with headlights ok right now.

I just got a CNB 605 and set it up as my new LP camera. The lens has an 850nm filter on it. Something I noticed is that if I set the D/N mode to Night and set the WDR to ON then the screen goes dark for a split-second every couple of seconds. If I turn WDR it stops. If I turn D/N mode to Day then it stops. What gives?

Am I the only one who has seen problems using infra-red to read printed license plates (not stamped). I'm using an 850nm emitter and an 850nm ir-pass filter. They appear as blank to me. I've seen this with an Ohio Veteran plate and a stock Indiana plate. So what do the big names like Extreme do with Indiana plates?

So here is what I have now with the CNB605 installed... Before: (day) After: (day) (The top plate is exposed as normal. The bottom plate has a smoked cover) After: (night) I need to get my hands on a printed plate to test it... Also, in my other thread I noted that the the combination of D/N mode in Night and WDR On causes the camera to black out for a split second every couple of seconds.

I'm still trying to figure out why tomcctv keeps saying that a cif image is better than a d1 image in this configuration: You get interlacing with d1, sure. That's why you de-interlace. The 18% calculation works for D1 but does it work for cif? At 320 pixels wide that means the plate is ~60 pixels wide. IS that enough detail to read a plate? I'm be aiming for 35-40% plate/screen ratio if I was forced to use CIF. But I wouldn't use CIF, I'd use D1 on a DVR that has a good de-interlace tha is tuned for motion. (aver's de-interlace #2 works great for my needs). And as far as lens calculations go - they work as expected for my camera setup which is a standard camera with a standard lens and IR filter. I can't figure out what part of the LP camera would change the physics of light to a point where the CCD size plus focal length cannot determine the field of view. Is an LP camer not simply a higher shutter speed camera with a standard lens and an IR filter? Again, folks, you guys are the experts on here and I'm just a hobbyist, but I like to think I've learned enough to be competent. If there is some explanation why CIF at 29.97fps is better for LP capture than D1 at 29.97fps (which is then deinterlaced) then just tell me - don't leave me sitting here wondering why I'm being told I'm wrong when I point out that it is counter-intuitive. Same with the lens calculations... Is 16mm on a 1/3" ccd through an 850nm ir pass filter REALLY a different FOV than the same withouth the filter?

Agreed. That's why I moved my own LP camera to be mounted dead center on the driveway. However, the longer lens camera is almost triple the cost of the REG-X. And the reg-x IS spec'd for 50mph at 40deg looking down and 40 deg looking across the road. So although the image would undoubtably be *better* with the car driving directly away from the camera rather than past it at an angle... If the "past it as an angle" image is perfectly satisfactory then it wouldn't justify the extra cost of the bigger camera.

I don't think GIMP will help you in this case... The brightness and contrast is set on the DVR at before the image is recorded. I don't think you will get the same effect altering the resulting jpg image after the fact.

Why do you keep saying CIF gives better image than D1?? I don't get it...

Your 18% calculation is more complex than it needs to be. If your image is 720x??? then make sure the license plate is at least 720*.18 = 130 pixels wide. For US license plates, if you can see past *both* sides of the car then the plate is too small. This is the smallest I would have the plates and still expect to read them... Too small: More thoughts:

I don't get what you mean by 120%. When I say 18% I mean the width of the plate is 18% of the width of the screen. Using US license plates (same character height as UK number plates, but the lettering is thinner and the characters are closer together) this means the car takes up the whole image.

Thanks!

tomcctv, The OP is talking about catching plates from cars that pass by in the closest lane within 2m of the camera as it sits on the side of the road. This is perfectly doable, even at a 35deg angle, within the 7.6m range of the REG-X. The current thought process is not calling for 35m range, more like 6m. Don't forget they are also talking about putting in a standard WDR cam that will get the vehicle description.

I have found the 18% number is a good baseline for my own system too. At less than that you an't tell the difference between D, O and Q. N, M and W blur together too. At 25% I can get a read every time as long as the plate would have been visible to the naked eye. I also have an LP cam (visible light) there the plate is 50% of the width of the screen. I can read your plate with no trouble at all. Heck, I can tell you what county you're in and tell if your stickers have expired! But unusual vehicles like the UPS truck with it's rear plate mounted hi-left pose a problem in that the plate does not pass through the tight shot. My struggles tend to be mostly with blurry images at night due to slow shutter times. The *real* lpr cameras can maintain a fast shutter at night.

automated license plate recognition is not the same as ALPR which in true terms means AUTOMATIC LICENCE PLATE RECOGNITION also known as anpr. the cameras dont see numbers its a very powerful algorithm set to read plates from upto a mile away and at speeds of over 100mph and your looking at $15.000 each. information from a ANPR camera licence number colour and make owners details tag check outstanding fines insured or not persons wanted. ALPR does not mean 100mph a mile away. It just means a computer converts the video image of the plate to text in order to do some further processing. Now, that *may* be a 100mph camera at a toll booth gathering plates of toll offenders... Or a 100mph camera on a police car reading the plates of oncoming cars to check for stolen/warrants etc Or it can be a REG-X in the entranceway of a gated community telling the gates to open becuase it's a known car, on on a parking enforcement car looking for scofflaws with outstanding tickets to clamp/boot them...

I didn't think the requirement for the license plates to be read and converted to text by a computer. I thought we were talking about recording a video image that woudl be read by a human? 18% is ok for a license plate. 20% is better. The bigger you get the more you you lose in focal width running the risk that cars will drive too far left or right and you'll miss the plate. Depending on the license plate font, O and D look very similar. Same with Q. Don't be surprised is the license plate you give the police is "DWM1234 or OWM1234" The police will tell you if either of the options you give them match the make/color for that license plate.

most dvrs will auto reboot now. the problem you are going to have is what make to use. and i will go back to the bosh camera again. am reading the spec for the camera and the engineers set-up dvr should record 2cif or 4cif ............ the camera will not work with D1 and will need to run 30fps. this system design is going to cost a lot of money if it was your own then yes TRY it out. but upto now nothing matches the camera and dvrs that have been listed are not compatible. and also the points of the camera being stolen or damaged. this is only because you have to mount it low because of the type of camera you are using. no camera should be installed in arms reach. What DVR do you recommend? (version 3.0) What is the effective difference between 4CIF and D1? Why will 4CIF work but D1 not work? If he goes with an EB1304 SATA for about $350 then he had 60fps D1 and can set the LPR channel to 30fps, and the car ID channel to 30fps, leaving the other 2 channels unused. You can't jsut keep saying "This DVR won't work, that DVR won't work..." without telling us which DVR you think *will* work.