Recommended computer for ALPR with 2 cameras?

W

wrybread

Pulling my weight
Sep 12, 2018
257
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San Francisco
I'm setting up an ALPR system using a Dahua IPC-HFW5231E-Z12E's and OpenALPR. Eventually I'll be using two cameras.

I'm using an older Thinkpad, the T530, with only 8 megs of RAM, running Ubuntu. Under powered I know.

I have the camera set at 15 fps.

Attached is my view of the license plate.

With this setup I'm missing maybe 1 in 4 plates in daytime. I gather from OpenALPR's support that this is probably from low computing power. I'll be on site later today to check the logs and confirm.

But anyway, I was wondering if there's some computer, ideally a laptop, that people have had good success with? Or a desktop if it's much better and/or cheaper.

Eventually I plan to have two cameras doing simultaneous ALPR through one computer.

Also, what do people think of that picture? I know it's more of an "overview picture" than an ALPR picture. Should I be tuning the camera settings differently? Any tips on that if so?

And what framerate are you using?

Thanks for any help.
 

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Zoom Zoom Zoom.

You don't need all that hill on the left side, or the wall on the right side. If you can zoom in more, please do. You only need to capture the area where vehicles will be. Anything outside of that range is just unnecessary, you are wasting CPU processing and making your plate images smaller which results in less accuracy for plate recognition as well.

If you are using low a low power device, here is a tip for you (this assumes you are using the paid for service and not open source).

You can draw an inclusion range, this way the computer is not spending its CPU cycles looking at an area of the image where there will not be any license plates.

You can actually configure this from the OpenALPR website, no need to even access your Thinkpad to make the change. From the OpenALPR site here is how you find it:

configuration -> agents -> configure -> configure (this should be the stream you are configuring at this point)

You will see a screen that looks something like this:


inclusion.jpg


The CPU can now process much faster by having to look at only the inclusion range.

If you are going to be running dual cameras, you would want to invest in a NVIDIA GPU that has CUDA processing. I have done tests with low end CPU processors, they are fine where there is no movement in the image but will ramp up to 100% when there is movement (like a vehicle, cat, person etc.) as it needs to process the images.

By added even a low end NVIDIA GPU, the CPU usage will not even blink where this is a processing requirement. I have tested it using GTX 1050ti card. I have a GTX 1030 card around here somewhere but I can't find it to test, but based on the GPU usage of only 3% - 4% I am quite confident a GTX 1030 would be more than enough for two cameras.

The 3rd tip I have, is run Linux not Windows if you are comfortable doing that. OpenALPR runs 20% faster under Linux than Windows, so you get more CPU cycles for video processing.
 
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Thanks for the fantastic tips. I just zoomed in a bit (see attached), do you think I'd be better off zooming even more? One factor is that I've been stubbornly trying to make this camera an "overview" cam as well as doing ALPR duty. I have a feeling I should give up on that and focus only on getting license plates. Thoughts?

I'll have a look at inclusion range later today.

And I'm running on Ubuntu, and alprd (currently using the paid version) was frozen this morning. The rest of the OS was happily running. I'm hoping that's rare? Could very well be this old crappy laptop.
 

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Robert G. said:
If you are going to be running dual cameras, you would want to invest in a NVIDIA GPU that has CUDA processing. I have done tests with low end CPU processors, they are fine where there is no movement in the image but will ramp up to 100% when there is movement (like a vehicle, cat, person etc.) as it needs to process the images.

By added even a low end NVIDIA GPU, the CPU usage will not even blink where this is a processing requirement. I have tested it using GTX 1050ti card. I have a GTX 1030 card around here somewhere but I can't find it to test, but based on the GPU usage of only 3% - 4% I am quite confident a GTX 1030 would be more than enough for two cameras.
Click to expand...
I definitely second this. If you get a laptop with an NVIDIA graphics card, you'll probably be able to run OpenALPR with both cameras operating at the full resolution and maximum frame allowed by the cameras themselves. It's night and day in terms of performance.
 
Definitely want to dedicate the camera to full time ALPR duties. Especially if you want night captures as you'll need to tweak settings so all that will be visible at night is the plate.

I've been running three cameras on an HP EliteDesk for over a year now. Also running Ubuntu but the open source version of OpenALPR dumping to a local MySQL database.

The service occasionally crashes for me and a restart fixes it. Not really and consistency to when it crashes so not sure why.

Is this the graphics card recommended? I'd be willing to throw $100 into the machine if it reduces CPU load. Sometimes the web server is super slow to load and reducing CPU usage might help. Gigabyte GV-N1030OC-2GI Nvidia GeForce GT 1030 OC 2G Graphics Card

Edit: here are a couple of my captures. I feed 30fps to the alpr daemon so it has more opportunities to read a plate.
View attachment 64250
View attachment 64251
 
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@th182 , I don't think the open source version has GPU integration. I read about some people doing it, but probably not easy.
 
wtimothyholman said:
I've been running OpenALPR with Ubuntu (Dell Optiplex 9020 with an NVIDIA graphics card) for nearly a year. It's been absolutely rock solid.
Click to expand...

@wtimothyholman can you confirm you are running the paid version? Or did you get GPU support in the open source edition?

I'm using the paid version, Windows 10 and I have never had it crash - not even once.
 
Robert G. said:
@wtimothyholman can you confirm you are running the paid version? Or did you get GPU support in the open source edition?

I'm using the paid version, Windows 10 and I have never had it crash - not even once.
Click to expand...
I'm using the paid version as well. Rekor has made a lot of improvements to the Watchman client over the open source version. Personally I'd recommend to anyone to pay the $5 / month / camera, just to have something that is as reliable as possible. Plus having the license plate alert feature is worth the money.
 
wtimothyholman said:
I'm using the paid version as well. Rekor has made a lot of improvements to the Watchman client over the open source version. Personally I'd recommend to anyone to pay the $5 / month / camera, just to have something that is as reliable as possible. Plus having the license plate alert feature is worth the money.
Click to expand...

It's been a while since I looked into the paid version. Wasnt there a cap on how many images you can have analyzed/month? If I have two cameras at 30fps I feel like I'd use that up quickly. Or does the software pick and choose what images are sent?

I have my open source version integrated with MQTT then my home automation subscribes to that and sends me alerts for a handful of plates.


Sent from my iPhone using Tapatalk
 
I don't think there is a limit on how many plates you can do per month. I do about 900 per day from a single camera.

The $5.00 plan (their cheapest) does have limits though.

1) They retain plate data for only a couple days I think

2) They do not identify the make/model of the vehicle on the $5.00 plan. I think you have to move to the $50 a month plan for that.
 
th182 said:
It's been a while since I looked into the paid version. Wasnt there a cap on how many images you can have analyzed/month? If I have two cameras at 30fps I feel like I'd use that up quickly. Or does the software pick and choose what images are sent?

I have my open source version integrated with MQTT then my home automation subscribes to that and sends me alerts for a handful of plates.
Click to expand...
There's no limit to the number of plates as far as I can tell. You have 5 days of data retention and the ability to put 5 plates on an alertable hotlist. For most homeowners, and many small businesses, that is probably sufficient.

The software does not try to save a plate for every camera image. Instead, it saves the best plate image out of a series of time-shifted plate images it receives from the camera. It is usually "smart" enough to ignore parked cars in the field of view, and very rarely do I get a "double hit" on a particular plate.
 
Robert G. said:
2) They do not identify the make/model of the vehicle on the $5.00 plan. I think you have to move to the $50 a month plan for that.
Click to expand...
In my experience, the make/model ID feature really isn't that useful. Having experimented with the higher tier paid version, I found that it was hit or miss at best during the day, and absolutely useless at night (not surprising for an LPR camera that is optimized to view plates).

One factor in this may be the other cars parked along the side of the road in my residential neighborhood. I assume that having partial views of multiple vehicles confuses the software to some extent. The DOT avoids this with brightly illuminated roadways and an optimal viewing angle of each vehicle.

My strategy is to run a separate camera that records a wider-angle view of each car as it passes, day or night. I can also use one of several free online databases to check the model of the vehicle associated with a given plate number, if the need arises.
 
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Robert G. said:
I don't think there is a limit on how many plates you can do per month. I do about 900 per day from a single camera.

The $5.00 plan (their cheapest) does have limits though.

1) They retain plate data for only a couple days I think

2) They do not identify the make/model of the vehicle on the $5.00 plan. I think you have to move to the $50 a month plan for that.
Click to expand...

Now I remember why I didn't go the paid route. Just too expensive for me as the $5 plan was not sufficient. With the open source version I have unlimited retention and it's free! I do miss out on the filtering that the paid version provides. So mine logs all plate read attempts regardless of confidence and it doesn't ignore parked cars (although with tweaking if the code it is supposed to).

Currently I have 611,000 records in my MySQL database that was started in April of 2019!! I intended to set up some routines to clean up the database automatically but never got around to it.


Sent from my iPhone using Tapatalk
 
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As far as the NVIDIA cards, is there some way to tell if the card's GPU is being utilized? I have another thinkpad (a different model T530) that has two GPU's (I think), an Intel and an Nvidia, so i'm curious to see which it's using. I'm using the paid version of OpenALPR in Ubuntu. I guess I could ask their support about this too.

As far as vehicle make and model, has anyone found this to be accurate? In my experience it's almost random, and just when I'm about to give up on it it'll get one right. On the plus side, when I hold a plate in front of my camera for testing, it always thinks I'm a Harley Davidson motorcycle.

I can also use one of several free online databases to check the model of the vehicle associated with a given plate number, if the need arises.
Click to expand...

Very interesting. Can you share which DB's you've had good luck with?

As far as duplicates and parked car filtering, I'm using the "webhooks" feature of OpenALPR, which sends a hit to my script on a remote webserver whenever it detects a plate. Interestingly when doing that it doesn't filter the results, so I get a hit for every single detection. I'm currently filtering with a lockout period (don't record the same plate within a 1 minute period), which misses people quickly turning around. I wonder if ALPR's built in detection is doing something more sophisticated. I'd love to be able to filter using the direction but if someone stops it'll often think they're going the other direction.
 
wrybread said:
As far as the NVIDIA cards, is there some way to tell if the card's GPU is being utilized? I have another thinkpad (a different model T530) that has two GPU's (I think), an Intel and an Nvidia, so i'm curious to see which it's using. I'm using the paid version of OpenALPR in Ubuntu. I guess I could ask their support about this too.
Click to expand...

You can install the NVIDIA driver using the same Ubuntu installer that you used to install the agent. Once that is done, you'll be able to verify the NVIDIA card is functioning with the 'nvidia-smi' command in Ubuntu. You'll also see that your CPU utilization will plummet while your camera frame rate increases.

I'm able to run two Dahua -Z12E cameras at 50 fps with full 2 MP resolution at about 25% utilization on the GPU, and 30% utilization on my CPU.

Very interesting. Can you share which DB's you've had good luck with?
Click to expand...
I generally use www.findbyplate.com. It's useful for determining if the plate you recorded was stolen from a different model car, or for getting more specific information (i.e. model year) about the vehicle.
 
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Wow, that's amazing, that service has found every plate I've fed to it so far (and for anyone else, there's a typo in the domain, I think it's findbyplate.com).

They have an API for automated lookups, but it's surprisingly expensive at two cents a lookup:

API Instructions

API Instructions to get access to license plate related information
findbyplate.com findbyplate.com

But certainly useful for regular web searches (or, I suppose, scraping, but that would probably violate the TOS).
 
wrybread said:
Wow, that's amazing, that service has found every plate I've fed to it so far (and for anyone else, there's a typo in the domain, I think it's findbyplate.com).

They have an API for automated lookups, but it's surprisingly expensive at two cents a lookup:

API Instructions

API Instructions to get access to license plate related information
findbyplate.com findbyplate.com

But certainly useful for regular web searches (or, I suppose, scraping, but that would probably violate the TOS).
Click to expand...
Thanks for pointing out the typo; I've fixed it in my original post.

If you're willing to pay you can even get the name of the person to whom the plate is registered, but I've read that you shouldn't rely on that information being accurate. These services don't have access to the latest DMV databases, only to older datasets that may not include new owners of a used vehicle.

Here's another useful trick: use www.vehiclehistory.com to get the VIN associated with a license plate. Then go to VINCheck® | National Insurance Crime Bureau to confirm if the VIN belongs to a vehicle reported as stolen. You're allowed five free lookups per day.
 
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