New to LPR? Considerations Before You Begin

wittaj

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FYI Plate Recognizer uses AWS Rekognition, so it is fairly accurate.

Depending on number of plates, OpenALPR is $8/month unlimited images and a utility was created by members here to store the plates.
 

reflection

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FYI Plate Recognizer uses AWS Rekognition, so it is fairly accurate.
Yeah, Rekognition is slick. And their AI/ML model will continue to improve over time, which should improve accuracy.

I'm sure Plate Recognizer is much more polished than my skunkworks project :). Trying to learn AWS.

Here's my thinking for an automated workflow:
1. BI detects motion and sends image to AWS S3.
2. Lambda function detects a new image in S3 and calls Rekognition to analyze the image.
3. Text results (plates) are stored in a NoSQL database like DynamoDB.

Number 1 is what I need to figure out. This might have to be a script that calls "aws s3 cp..."
 

Ballistyx

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We installed our roadside camera initially just for motion notifications, but have recently felt the need to identify vehicles due to local crime (and the police constantly calling me to ask if I might have footage of suspicious vehicles!).

Ideally, I'd like to be able to at least manually read number plates night and day - ANPR or even NPR is probably not absolutely necessary - and also need to cover the driveway entrance and hopefully the mailbox (circled on right).

Distance to these vehicles is approx 15m, and they will be travelling around 80km/h. Camera is maybe 30ºH, 15ºV.

Currently using camera's IR lighting, but have toyed with the idea of mounting an illuminator on the corner of the shed (circled on left), because I get far too many false alerts from raindrop reflections.

So, from what I'm reading, I need maybe 4MP, 1/1.8" CMOS, fast shutter, varifocal lens, small aperture... now all I need is the local suppliers here in NZ to let me filter their products by these specs and I'm good. Unfortunately...

I see most recommendations are Dahua, but it appears the local stockist only has the crappy 1/3" sensors. I'll keep looking for just the right combination, but if anyone can suggest some particular models of various brands that fit the bill, it would be great :)

(I'd consider a dedicated camera for cars, as well as the existing one, if I thought I could possibly feed an additional cable through the conduit that I spent so much time and effort digging in!)
cam1.png
 
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Check with Andy from Empire Tech for Dahua cameras. He can supply them at great prices and ships anywhere in the world. Given the information you've provided I'd say a 5442-Z4 would more than work for you. Lots of zoom to get good captures. LPR is an art and the cameras used are dedicated strictly to LPR. Some "light" reading for you as well.

LPR

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Andy's instructional videos -
 

samplenhold

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Thanks, Sebastian! I'll check it out :)
Like I say, I don't know that I need to read every single plate that passes, but I'd like to be able to when I need to lol
It has been two years since I made this post. I have learned a lot about LPR from my experience, other's postings and questions, and how my needs morphed over time.

I did not spend much time on building a database of plates. I have been watching those threads and maybe someday when life gives me some time, I will get back to that. I rarely have the need to see if a certain car came by before. So right now I just have the video, which is stored for about 3 weeks.

Contact Andy ( @EMPIRETECANDY ) as I am pretty sure he ships to NZ. I have bought all of my cams directly from him by sending him an email at kingsecurity2014@163.com and paying through PAYPAL. You do not need a 4MP on a 1/1.8" sensor for LPR. The conventional cam most of us use is the Dahua HFW5241E-Z12E which is a 2MP on a 1/2.8" sensor. Most use this cam since it has good zoom and IR distance.

The reason folks like a 4MP on a 1/1.8" sensor is to get good video in color at night. But for LPR you will not be using color at night, you will be in B&W using IR. This is to ensure that you can freeze motion well enough to read the plate by using a very fast shutter speed, like 1/2000. LPR is all about the snapshot and not the video. So it is most like sports photography than movie making.
 
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Ballistyx

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The reason folks like a 4MP on a 1/1.8" sensor is to get good video in color at night. But for LPR you will not be using color at night, you will be in B&W using IR. This is to ensure that you can freeze motion well enough to read the plate by using a very fast shutter speed, like 1/2000. LPR is all about the snapshot and not the video. So it is most like sports photography than movie making.
Cheers.
While I know that there's no one-size-fits-all solution, I do hope that, in addition to the clarity to be able to at least manually read plates when necessary, I can get decent low light definition rather than the blur I currently get!

cam2.png
 

David L

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Cheers.
While I know that there's no one-size-fits-all solution, I do hope that, in addition to the clarity to be able to at least manually read plates when necessary, I can get decent low light definition rather than the blur I currently get!

View attachment 146388
Optical Zoom will be the key to your success.
 

samplenhold

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Cheers.
While I know that there's no one-size-fits-all solution, I do hope that, in addition to the clarity to be able to at least manually read plates when necessary, I can get decent low light definition rather than the blur I currently get!

View attachment 146388
Compare that shot with these. The day is for you to see how zoomed in and the night is to see how well the plate can be seen.

LPR East 2022-05-25 03.01.24.520 PM.jpgLPR-E.20210306_132401944.114.jpgLPR East 2022-10-11 09.29.06.531 PM.jpgLPR East 2022-05-02 09.35.30.921 PM.jpg
 

Ironheadchop

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The big key is to run daytime at 1/2000 shutter and then either force it to night settings B/W 45 minutes before sunset and 45 minutes after sunrise so that it has something to focus on, or use the utility posted on the forums that will set focus within the utility.

I ran mine 24/7 using the nighttime settings until I decided to give that utility a try, so now I run color in daytime with 1/2000 shutter
What utility are you mentioning here?
 

wittaj

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What utility are you mentioning here?
This one

 

pbc

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Helpful thread. Been using the 5241-z12 for a while trying to capture 2 lanes which poses challenges.

Curious,are their significantly better options out there for double or triple the price?

Or would some sort of long range IR device be better recommended?

Have been using 1/500 exposure and get captures like these (need to work on focus):

01563A5A-0C94-4841-8E13-AD0217348EBA.jpegD7CA6B27-7A87-488C-88C0-4785D98BECC6.jpeg

Juar changed to 1/2000 and had a neighbour sit there for me to change settings. But struggling with many plates that are a bit dirty in terms of lighting them up with IR.

So was curious what other camera options are out there and or if external IR would be a better option?

In the meantime will keep tweaking when I get a chance!
 

samplenhold

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Both Dahua and Hik make cams specifically for LPR, but they do not have the amount of optical zoom as our trusty 5241 Z12E cams.

How far away are these caps from? Can you zoom in more?

There will always be problem plates. Some you will just never be able to get. I have a few that come by that to get the full plate number, I have to step through frame-by-frame.
 

wittaj

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Helpful thread. Been using the 5241-z12 for a while trying to capture 2 lanes which poses challenges.

Curious,are their significantly better options out there for double or triple the price?

Or would some sort of long range IR device be better recommended?

Have been using 1/500 exposure and get captures like these (need to work on focus):

View attachment 151098View attachment 151099

Juar changed to 1/2000 and had a neighbour sit there for me to change settings. But struggling with many plates that are a bit dirty in terms of lighting them up with IR.

So was curious what other camera options are out there and or if external IR would be a better option?

In the meantime will keep tweaking when I get a chance!
With capturing plates, it is all about making the plate as large as possible, and that is simple physics and optics. Not many cameras have this amount of zoom.

So for some field of views and angles, trying to get two lanes can be problematic.

The right kinds of external IR will help (focused versus wide IR).

But we have to recognize we won't get every plate. Some are dirty or rusty or temp tags, etc.
 

pbc

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Both Dahua and Hik make cams specifically for LPR, but they do not have the amount of optical zoom as our trusty 5241 Z12E cams.

How far away are these caps from? Can you zoom in more?

There will always be problem plates. Some you will just never be able to get. I have a few that come by that to get the full plate number, I have to step through frame-by-frame.
With capturing plates, it is all about making the plate as large as possible, and that is simple physics and optics. Not many cameras have this amount of zoom.

So for some field of views and angles, trying to get two lanes can be problematic.

The right kinds of external IR will help (focused versus wide IR).

But we have to recognize we won't get every plate. Some are dirty or rusty or temp tags, etc.
Distance is about 100-120 feet. Unfortunately, short of putting up a 3rd camera in the spot (one is general viewing, the other is dedicated LPR), stuck with trying to capture two lanes with the one camera so can't zoom in much more (I'm at 900 on the manual zoom).

Was just curious if there were better cameras out there with sharper focus and/or better IR, dedicated for LPR. Otherwise I could possibly look into external IR, not sure what's recommended for that distance?
 

samplenhold

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Ok, so you have one cam for two lanes at 100-120 feet. When you say two lanes, are you talking about a normal suburban neighborhood street? Like 24 feet wide? Similar to the map view below?

8.JPG

If so, then your LPR setup is comparable to mine. Show a daytime shot so we can see what the situation looks like.
 

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looney2ns

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The product says "Pulsed mode allows syncing with a camera shutter for industrial, machine vision, and ANPR/LPR applications. " I wonder how that would work?

Also, would this product allow for a local 120v power source?

Guess I'm still hoping for the white light strobe which is supposed to be invisible to the human eye.
Lots of info on the manufacturer's website.
 
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