License Plate Camera VS Regular IP MP

[mattaggie 0]

Currently we have no cameras in our front parking lot so I need some advice on what kind of camera to put there. My confusion is over License plate camera vs standard outdoor IP MP camera. We have a 3MP camera for our back area and while it gives a great picture, I noticed that I am unable to read any license plates. But my question is, does a license plate camera function well at showing you the scene other than the license plate? Or do I need a good IP camera plus a license plate camera? Most of our issues occur during the daytime but of course if something does happen at night, I'd like the camera to give a good image of that as well. So I guess my question is how well do license plate cameras capture events other than merely the plate itself. I use Geovision cameras.

[MaxIcon 0]

There are 2 key issues with LP cams - field of view/pixels per foot, and lighting.

 

To get a readable plate, you need enough pixels per foot. This is usually done with a longer zoom lens. Resolution combined with field of view need to give you 80 ppf, give or take, and more is better. As a result, a plate cam will have a narrow field of view, so you need both a wide area cam to watch what's going on and a narrow area cam to capture the plate.

 

Lighting is the other tricky part, and will depend a lot on what cam you choose. Most inexpensive cams will do fine during the day, but may struggle at night, depending on the local lighting. Capturing front vs rear plates at night involves different levels of lighting (headlights on or off, brake lights on or off, is the plate lit, is your IR strong enough to reach the plates, and so on). There are lots of solutions to this, usually involving money and/or special setups.

 

Best bet is to set up a dedicated camera with a lens that gives you 80-100 ppf in the area you expect to capture a plate and see how the results come out. Then you'll know what you need to do to improve it.

[buellwinkle 0]

 

Funny you should ask because I put up my first LPC (license plate capture vs. license plate recognition) camera last week and been tweaking it. I've done LPR several times before, but this is likely what most people here want to do, which is capture plates in videos, but not do LPR. It's a Hikvision mini bullet, the ds-2cd2032-i 12mm. I've getting very good plate captures day or night now at about 50-60' and it's awesome. Even full on headlights at night. Click on the image to see it bigger, then click on the 4 arrows in the lower right to see it at the full 3MP so you have an idea of what is possible.

 

 

 

There's really not much difference between a camera sold for LPR vs. a decent camera, just marketing. Also most sold for LPR are not LPR, but just LPC. The different is LPR implies that it's doing character recognition for storing as text and doing event processing on a plate match. BTW, I've seen the Geovision LPR camera in action and there's likely now way I can see that working for true LPR, at best LPC and even then, the image is not as clear as with the cheap Hikvision.

 

[tomcctv 190]

BTW, I've seen the Geovision LPR camera in action and there's likely now way I can see that working for true LPR, at best LPC and even then, the image is not as clear as with the cheap Hikvision.

 

You must of been looking at the wrong geovision

One thing geo does and does well is LPR

AND IS ALSO 1 of 4 companies which can be licensed to use national vehicle data bases.

 

 

 

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You have an existing geovision system I would look at installing LPR software onto it.

 

This has a lot of good features

[buellwinkle 0]

 

Could be, but the one I've had looked at was this one - http://www.geovision.com.tw/english/Prod_GVLPRHybridCam.asp

 

You can make out plates, but not any better than a Hikvision camera. Has a 1/500th max exposure and the pictures just came out dark and the plate was readable but you had to strain to see it. Do you have a better experience with their LPR IP cameras?

 

[tomcctv 190]

 

Yes lots with geo LPR

 

Yes you image is good but it's controlled I.e cul de sac

 

Show a moving image something 20 mph in dark the hik can't do that. On its own run it through a GV LPR box it might.

 

 

 

But since ops question was something better than just catch image of plate and he is already using the platform (geovision) and its for a parking lot.

Then geo. Can do a lot for him

 

Log plates ... Create data base of car owners ..... And with licence from DMV log owners of cars ....... Check if plate should be on car

 

[mattaggie 0]

 

I don't need it to log every plate into the software that comes through. I just want to be able to read the plate if I'm researching an incident. And there are 4 exits from the parking lot, so it sounds like I would need a LPC camera pointed at each exit.

 

Would an higher MP regular camera be able to get plates in my scenario? Obviously vehicles will be moving slowly and usually stop before entering the road. I'm confused as to what a 5MP camera does vs a 3MP. My current 3MP cannot read the plate (Im sure it could if I had it zoomed into a specific spot, but its covering a wide area. Would the 5MP camera allow me to zoom in from a large frame more? Or does a higher MP just add more area covered and not more detail?

 

[buellwinkle 0]

 

It gets pretty expensive with LPR and you are typically charged per lane and while their software is one of the least expensive LPR solutions out there at about $800/camera, it's far from the best.

 

My cameras is set at 1/200 second exposure, I'm pretty sure I can capture a car going much faster. Certainly fast enough to get a plate going in/out of a parking lot. The only reason we do LPR is to activate a gate automatically based on a plate match. From a security standpoint, not sure you would benefit from LPR as you just want to see a plate in a video.

 

[cglaeser 0]

AND IS ALSO 1 of 4 companies which can be licensed to use national vehicle data bases.

 

What is the national vehicle data base?

[tomcctv 190]

AND IS ALSO 1 of 4 companies which can be licensed to use national vehicle data bases.

 

What is the national vehicle data base?

 

 

Sorry usa it's vehical registration

[cglaeser 0]

AND IS ALSO 1 of 4 companies which can be licensed to use national vehicle data bases.

 

What is the national vehicle data base?

 

 

Sorry usa it's vehical registration

 

What do you mean by "geovision is 1 of 4 companies which can be licensed to use vehicle registration" ? Is that for law enforcement? civilian use?

[thewireguys 3]

 

 

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All most any MP camera with the right lens and exposure settings can get plates on a stationary vehicle.

[buellwinkle 0]

That was not a stationary vehicle.

[ssmith10pn 0]

That was not a stationary vehicle.

 

 

Well then he's about to take the curb out.

 

Plus not many states have front plates.

[buellwinkle 0]

Just showing an example, I have plenty every day, a different speeds, different plates. In California front plates are required, but many here in the O.C. do not follow that rule, but go to L.A. and you'll get a ticket. But you can aim the camera at rear plates just as easily and could have done if I wanted too by my primary goal for this camera was mail box theft and license plate capture was a bonus. Rear plates are way easier to capture for 2 reason, most are lit or at least required to be lit by law, and you don't have to overcome headlights, especially large ones like from the example I provided.

 

I my specific case, if I wanted rear plates, I would have to go with a 25mm lens to capture them from the other direction. I tried with a 12mm but in my case, it's just too far away for a 12mm.

 

One caveat, as I've said before with plates with IR cameras, including the Geovision LPR is that you can not capture plates with red characters, for example Illinois license plates. If you are not sure, ask the manufacturer if their cameras can capture Illinois plate number at night (Alberta if you are in or near Canada).

[tomcctv 190]

I don't understand why you say the cameras can't pic up red or blue plates..... Day time should not be a problem and at night both red and blue would show black under IR.

 

Yes geo does pic up red blue black yellow so does aver .. Avigilon ..PIP.

 

The problem is using standard IP as a Anpr camera it will get plates but only as a capture. Only with a good enviroment

[MaxIcon 0]

That capture was 100 ppf, which is pretty ideal at night if the lighting is good and the camera is pointing directly at the plate. As the angle gets greater, like if you're capturing on a through street with the cameras mounted back from the curb (like on a house), there's a trade-off between distance and plate angle.

 

On my Hik 2032 setup with a 25mm lens, mounted at the corner of the house, cars are about 80' away before I can get a good angle on the plate. Any closer, and I get a good view of the side of the vehicle, but the plate is at too much of an angle. At this range, the camera's IR is pretty useless, especially on this 2032, which has lost some of the IR LEDs.

 

As a result, I can get good readable images in the daytime, but at night, there's no reliable legibility of the plate.

 

The other problem I see is that cars are going by too fast at night for the auto exposure to correct. By using fixed exposures, it improves things, but the only way I get readable plates at night is if another car is coming and lights up the plate of the first car. Different cars have different lighting; some don't light the plate at all.

 

So, if you have a good choke point, where you can get a reliable, head-on, full frame image, you can make it work. Other situations, like a house with a big yard set back from a through street, can be more challenging with inexpensive cams using M12 lenses.

 

For the OP, having dedicated cams at each entrance/exit with a good FOV should provide a usable solution.

[buellwinkle 0]

It's all about the settings, you don't need to have fixed exposure, just a fast max exposure, about 1/200 and kick gain down a bit, maybe 75 or so the image look close to black except plates and headlights. My image is very dark, then the car turns the cul-de-sac and it's instant bright lights and there's no adjustment period, do you want me to post the video. I don't know the angle but my camera is mounted on the fascia board of my garage roof just above the garage door. The camera is pointed to the opposite end of the property which is about 50' if it was a straight line, but angled towards the street it may be 60' or so. The distance between the camera and curb is about 30'. If I had to guess angle, in this picture, about 31 degrees, cars towards the middle of the street that I captured, about 38 degrees. Those are good plate capture angles.

 

As for 80', that's pushing it for that IR, but I get plate reflectivity but your IR 's diminishing/failing. May be worth getting a decent illuminator or maybe an indecent one.

 

As for red letter plates, if you can read red on white then that's awesome because none of my cameras see red at night, just comes out white. For example, look at the plate in this picture and try and read the word California which is red above the plate number, I can't. If you have an image from a camera of red letter on white background or white letters on red background taken at night without an IR filter (nigh mode), please show us. Sure, if you have an IR filter on the camera then you can see red vs. white, but then you can't use IR illuminators.

[tomcctv 190]

If the letters were same size of licence plate then yes you would.

 

Move away from your state say an area with red on white or blue on white or black on yellow are you saying there is no chance of plate capture ???

 

Get yourself a geovision

[buellwinkle 0]

Which Geovision because the LPR one I looked at did not see red at night, the one I mentioned earlier. Heck, even the sample images from Geovision website are not showing red. Do you have one of these cameras? Can you show us a night shot showing red characters?

[buellwinkle 0]

Check this out on Geovision website - http://www.geovision.com.tw/english/Prod_GVLPRHybridCam.asp

 

Look at the sample images, pretty cool right except the state name is missing, hmm. So I dug deeper and those are uniquely Washington state license plates.

 

This is what it looks like during the day. See "Washington" in red.

[tomcctv 190]

If the words Washington were same size letters then it would

 

 

Is it not the licence plate number were talking about ???

[cglaeser 0]

As for red letter plates, if you can read red on white then that's awesome because none of my cameras see red at night, just comes out white. For example, look at the plate in this picture and try and read the word California which is red above the plate number, I can't. If you have an image from a camera of red letter on white background or white letters on red background taken at night without an IR filter (nigh mode), please show us. Sure, if you have an IR filter on the camera then you can see red vs. white, but then you can't use IR illuminators.

 

License plates in states like CA use more than high contrasting colors to read plates at night. They also use a retro-reflective coating on the area that is not the ID. So, yes, the red on a CA plate is difficult to read in part because it shows up as white, but also because the red "California" on the plate is retro-reflective. This is purely speculation, but I think that if the ID on CA plates was red, it would not be as easy to read as blue, but would still be readable in many cases because the ID would not be retro-reflective while the rest of the plate would be. Just guessing, though.

[buellwinkle 0]

If the words Washington were same size letters then it would

quote]

 

Show me, prove me wrong. Then why can I see the registration stickers on the plate, but not the larger WASHINGTON?

[cglaeser 0]

If the words Washington were same size letters then it would

 

Show me, prove me wrong. Then why can I see the registration stickers on the plate, but not the larger WASHINGTON?

 

It's not just the color, contrast and size of the letters that matter at night. It's also the retro-reflective coating. Red on white is a poor choice for night identification, but if the white is retro-reflective and the red letters are not, that will make it much easier to read at night with an IR camera.

Edited January 19, 2015 by Guest