South African number plates

[Jacques Britz]

Hi,
First of all, thank you for the great work that you are doing.
I'm a .NET developer myself and is currently working on an ALPR
solution for our local community. (Non profit)

My ultimate goal is to have an ALPR solution run on a Rasberry PI.

Would it be possible to change your library to recognise South African
number plates? (How much effort would it be? Will I be able to do it
myself?)

The EU mode works well when then it's a close up photo.(86% match)

Please let me know.

Regards
Jacques

[Matt]

Jacques,

Just looking at the South African number plates, they look fairly similar to the European ones.  I think the font may even be a derivative of the German plates.  As-is, I suspect you'll get reasonable performance out of the library -- but it can, of course, be improved.

The best way to improve the detection accuracy would be to crop out many license plate samples and retrain the detector.  Currently the EU license plate detection is based on roughly 1000 or so positive image samples.  If you are able to find and crop out a few hundred to a few thousand South African license plate images, the accuracy would be significantly improved.  This repo has examples of what images you would need.  Basically, they need to be cropped around the license plate (including a little bit of car/truck bumper is a good thing).  The imageclipper program (with a fixed aspect ratio) is helpful for doing this type of manual cropping:

https://github.com/openalpr/train-detector

[Jacques Britz]

Thank you Matt.

I will give it a try and let you know. 

[Mark Theunissen]

Hi Jacques

Did you ever get training data together for South African plates? There's a Github issue here too (https://github.com/openalpr/openalpr/issues/129).

I'm also interested in Raspberry Pi + South African plates. I've built OpenALPR and made it available here: https://github.com/marktheunissen/lpr-deps

I've also approached Package Cloud and they should be providing a proper APT archive soon. 

- Mark