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kw23

car reg plates

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I want to buy a camera that is good enough to record vehicle reg plates from about 40-50 feet in daylight and at night. probably the best would be an ip cam, but I'm really looking for the chepest option, I have an apple powerbook recording my existing camera (a ycam ip camera) which is not good enough to deciper the reg. ( I want to be able to read the reg myself on viewing the recorded footage not use software to do this). what camera could I buy for this?

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KW,

IP Camera. HD Camera, MegaPixels may easily lead you confused and wrong selection for your app.

Critical Factor is Lens Quality, Focus, and Lighting.

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If your not looking to spend that much, good luck with that. And generally, an LPR is analog.

 

 

"i want to be able to read the reg myself on viewing the recorded footage NOT use software to do this"

Edited by Guest

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KW,

IP Camera. HD Camera, MegaPixels may easily lead you confused and wrong selection for your app.

Critical Factor is Lens Quality, Focus, and Lighting.

 

could I do it with a 12mm lens, or bigger? I live in the uk (fairly large reg plates)

 

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I should add - the cars will be stationary, or moving slowly.

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On a 4CIF/D1 analog camera you'd need atleast a 15mm lens to be able to read a reg plate. But you will also need to well target the camera because the scene you will capture will have a width of 10 feet.

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On a 4CIF/D1 analog camera you'd need atleast a 15mm lens to be able to read a reg plate. But you will also need to well target the camera because the scene you will capture will have a width of 10 feet.

the way i have done our reg plate is we installed a lighting column post light on a concrete pad near end of driveway and the camera was mounted approx half way up the coloumn inside looking through a small pin hole and glass installed over lens will try and take a few shots tonight with camera flash to show.

Edited by Guest

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My DIY LP cam setup consists of

 

[*] An Arecont Vision AV1310DN 1.3MP IP camera with a 1/2" sensor (set to permanent night mode)

[*] 25mm Computar megapixel manual iris lens

[*] 37mm IR filter (blocks visible light)

[*] RayMax RM100 940nm IR illuminator (to make reflective plates legible at night)

 

Total cost ~$US1300

 

This setup has been working well for a couple of years now. The only weaknesses are 1) non-reflective plates are illegible at night, and 2) because the manual iris lens has a fixed aperture a plate can get overexposed when bright sunlight is shining from exactly the right angle. I figure 2) could be overcome with an auto-iris lens, but since the AV1310DN does not support auto-iris lenses I would need a new camera as well as a new lens, so that experiment has been put on the back burner.

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My DIY LP cam setup consists of

 

[*] An Arecont Vision AV1310DN 1.3MP IP camera with a 1/2" sensor (set to permanent night mode)

[*] 25mm Computar megapixel manual iris lens

[*] 37mm IR filter (blocks visible light)

[*] RayMax RM100 940nm IR illuminator (to make reflective plates legible at night)

 

Total cost ~$US1300

 

This setup has been working well for a couple of years now. The only weaknesses are 1) non-reflective plates are illegible at night, and 2) because the manual iris lens has a fixed aperture a plate can get overexposed when bright sunlight is shining from exactly the right angle. I figure 2) could be overcome with an auto-iris lens, but since the AV1310DN does not support auto-iris lenses I would need a new camera as well as a new lens, so that experiment has been put on the back burner.

 

 

How far can you read plates with that setup?

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Are the cars moving or are they at a stop sign or something like that when they are 50 feet away? Have you considered a PTZ

camera to move around at will?

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To what kind of use is this LPR camera coming to? 40-50ft seems a bit long distance for normal LPR usage (LPR for gate control etc.).

 

If possible, installing the camera closer would probably make the system way cheaper than it is with 40-50ft, i wouldnt personally install LPR camera more than ~15ft away from the plate in case of gate control or such.

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I just recently installed an analog LPR off a gate house and the stop sign down the road was roughly 50 feet away. The lens on the camera was 5-50mm and it's working out great. The camera was under 400usd. I also installed two 1.3mp cameras off the guard house so I used an analog DVR as an encoder and my NVR records the analog LPR.

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this is how ive done my own umber plate, its a covert style bullet cam mounted inside the post with security screws/bolts and sealed with a black silicon style sealant to the light post, heres a day shot of what you see

1028022790_photo1.JPG.4096f49d79a65533faad80569890d072.JPG

545209679_photo209.JPG.64c4f7231bba04c845bc17d378069b18.JPG

numplate.thumb.JPG.4e1536f6e6a48e2dbf97086fc3bec1d8.JPG

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This is the best my ptz can muster zoomed in 27x and catching cars going around 40mph as the sun sets. This isn't a solution to consider of course- it just got me curious what I could get. You should consider what Lucky is doing- perhaps a similar setup.

 

 

 

1080071990_lpr1.jpg.0986309c34e6d19d489cd569c4eeb523.jpg

lpr2.jpg.c60d3c64b3f52564760794916fb30c71.jpg

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its a covert style bullet cam mounted inside the post with security screws/bolts and sealed with a black silicon style sealant to the light post

 

That is awesome! " title="Applause" />

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How far can you read plates with that setup?

 

I have captured plates from clear across the cul-de-sac, probably 60-70 feet, even at night.

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1. Your focal point should not be much wider than a single car driveway

2. Angle should not be greater than 30 deegrees

3. Infrared needs to match your states color contrast. Different states use different color temperatures for best result.

4. Lighting must match focal distance

 

If you are looking for a stationary plate capture the above should work.

If you are looking for a "In motion capture" The camera should use a CCD sensor instead of CMOS

 

Frame rate should be 30fps to 60fps and shutter speed above 2400.

 

Does anyone know of a IP camera with CCD ?

I know NST has a HD-SDI CCD high speed camera designed for LPR, Red light etc but the low end is $1150

They also have a speedbump cameras available in analog, HD-SDI and I think IP. The analog gets a great image as the focal point is right on top of it.

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My DIY LP cam setup consists of

 

[*] An Arecont Vision AV1310DN 1.3MP IP camera with a 1/2" sensor (set to permanent night mode)

[*] 25mm Computar megapixel manual iris lens

[*] 37mm IR filter (blocks visible light)

[*] RayMax RM100 940nm IR illuminator (to make reflective plates legible at night)

 

Total cost ~$US1300

 

First, not quite sure how total cost is $1,300 when the RM100 can cost that much by itself, but I concur with the setup, but the RM100 940nm may be underpowered for this. I would recommend the RM100 850nm as it's at least twice as bright and it costs less. At 50', the RM100-30 with 850nm would be at it's maximum distance for this purpose.

 

Also, I would go with a varifocal lens, say Fujinon 5-50mm so you have more control over it, costs is cheap, maybe $100. It's not effective to capture an entire scene, you need to zoom in on the plate area, at most capture the front of the car or rear from edge to edge. If you try and capture a large area, you'll need to get a much brighter illuminator, maybe the RM200-50 and wider illuminator to make the scene evenly lit because the plate will be so small relative to the scene, it won't get the correct exposure for it. I would say make sure the plate represents at least 5% of the image. For 40', our lens is set to about 30mm, so 25mm used above would be the minimum. We don't use a filter of any kind other than the IR Cut filter in the camera.

 

Any decent low light performance cameras will do for this. We use an Axis Q1604 (not the -E because it can't fit a longer lens) which I believe is only about $800USD but you may be able to use a good ACTi box camera for a fraction of the price if you want an IP cameras but you can use analog. I would not go for more than a megapixel. We run our Q1604 at VGA resolution because it's zoomed in on the plate, that's more than enough resolution. Also, it's set for MJPEG because it provides a clearer single frame shot to me than h.264. Also turn down any sharpening and kick up contrast.

 

Shutter speed, this is where it gets interesting. Milestone LPR recommends like 1/500th as the max exposure for a car going 30mph, but we run it at slower speeds and it's good enough, maybe 1/60th or 1/120th of a second. Also, we run the camera at 4fps, that seems to be sweet spot for capturing the plates without too much excess.

 

Also, angle of view makes a difference. I would recommend no more than a 30 degree angle from the camera to the plate at least in the US where many states use embossed plates.

 

With our setup, we can read plates up to about 40mph 24/7, very sharp and clear distinct numbers.

 

Having software to convert the plate numbers to text is more awesome than you can image because say there's a crime that has been committed. With a list of plate numbers, you can determine how many times and when the suspect has passed your camera in the past, maybe tie it in with past crimes. You can set alerts to text you if they return.

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First, not quite sure how total cost is $1,300 when the RM100 can cost that much by itself

 

IIRC I paid around $800 for mine maybe 2 years ago. Worth every penny!

 

the RM100 940nm may be underpowered for this.

 

Agreed. Unfortunately I have some special circumstances where I need to keep as low a profile as possible, and 850nm LEDs are extremely noticeable - especially super-bright ones like those on the Raymax. Even the 940nm LEDs are visible if you're looking right at the face of the iluminator.

 

Also, angle of view makes a difference. I would recommend no more than a 30 degree angle from the camera to the plate at least in the US where many states use embossed plates.

 

Angle is especially important for software OCR. For Human Character Recognition you can deal with more skew. However, some vehicles like pickup trucks with the license plate recessed into the rear bumper or SUVs with a big spare tire mounted on the back can block your line-of-sight unless you have a straight-on view.

 

Having software to convert the plate numbers to text is more awesome than you can image

 

Care to mention which software you use and how much it costs?

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Funny you ask because LPR has been stressful source of much fun for our installers and me. First I selected IPConfigure, runs as an app inside an Axis camera and costs about $1,500. Conceptually very cool, no PC required. Does not work well at all. Accuracy was lacking, would not trigger an event on a plate match and it took about 15 seconds per plate, and occasionally locked up the camera requiring a reboot. Would not recommend, LOL.

 

Next I tried Milestone LPR. Cost about the same, it's like $300 for the LPR Base license, and $1,295 per camera. This worked a lot better. The plates were recognized, has been stable for 2 weeks and it triggers events on plate match and you can maintain multiple lists. I would recommend this as it's industrial grade from a known vendor and support has been very good.

 

Next I tried home grown. Of course the advantage is that it's free, but clearly there's more effort involved. I'm using open source LPR scan software from www.openalpr.com and it's pretty accurate. You give it a picture and it finds the plate. They have a demo on their site - http://www.openalpr.com/demo.html where you can give it your picture and it will return the plate number. I have it running on my PC, and I can take pictures captured by Milestone and put them through this and I get similar results. I'm working on a VB script on Windows that takes snapshots from the Axis camera and passes it openalpr and just in the early testing stages as I just wrote it today. The only problem with VBS is that it triggers all sorts of virus warnings, oh no, the sky is falling. So it's more for prototyping but I'll probably have to take the VB script code and create a program in VB.net.

 

Nothing is perfect and sometimes all of these pick up printing on the side of a car or a bumper sticker as a plate, but for the most part they get the plate number. Q's seem throw it off because it may have trouble selecting from a zero. Also, thick license plate frames may throw it off. All three solutions work with plates from the US or Europe but have region specific settings. For example, if I chose California, I get better accuracy than if I just pick all of the U.S. but may suffer a little on plates from other states.

 

Camera settings make a big difference. Set sharpening way down and contrast a little up. Setting resolution lower makes for faster plate recognition. I use 640x480. Also, most seem to recommend 4fps and that works well for us. Also, don't use h.264, it's not as clear per frame as mjpeg for this purpose.

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Which camera are you using?

 

Thanks.

this is how ive done my own umber plate, its a covert style bullet cam mounted inside the post with security screws/bolts and sealed with a black silicon style sealant to the light post, heres a day shot of what you see

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