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Not recognizing eu number plates #177

onno182 opened this Issue Aug 12, 2015 · 4 comments


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onno182 commented Aug 12, 2015

EU number plates do not get recognized, while US do.


When using using attached image:

alpr -c eu lp.jpg
No license plates found.

alpr -c us lp.jpg
plate0: 1 results
- L87E confidence: 83.688
plate1: 7 results
- 87RSR confidence: 88.2947
- 87R5R confidence: 79.1333
- 87RR confidence: 76.2563
- 87RBR confidence: 73.8303
- 87RS confidence: 72.3227
- 87R5 confidence: 63.1613
- 87RB confidence: 57.8583


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onno182 commented Aug 12, 2015

Anyone have any ideas?

@matthill matthill added the question label Aug 12, 2015


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onno182 commented Aug 12, 2015

Incase someone has the same problem, setting the following seemed to have fixed the problem.

detection_iteration_increase = 1.1


detection_iteration_increase = 1.5


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matthill commented Aug 13, 2015

I ran OpenALPR on the image. If you run 100 images through that look similar to this, you'll probably get 98 correct results. There's just a small chance that it doesn't pick up the features. It's just the nature of computer vision -- it will never be 100%. There's some discussion about this in the forum:!searchin/openalpr/computer$20vision/openalpr/vpky-7qFXSI/F_Fcjy9cqt4J

Changing the detection_iteration_increase value results in essentially a different chance at reading the plate (since the area being analyzed will be ever-so-slightly different). If you changed it to 1.09 or 1.11, I suspect that will make it read correctly as well.

@matthill matthill closed this Aug 13, 2015


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BramWerbrouck commented Sep 10, 2018

I have a similor probleem, it’s like the API cloud Version Works corrector than the ‘general’ version.
when I Change “us” into “eu” (because I want to read licence plates from Europe) I get An Error.

I used this in my python script:
Plate = ALPR(“eu” , “/etc/openalpr/openalpr.conf” , “/usr/share/openalpr/runtime_data”)

The EU seems logical to me, but it doens’t work.. what do I do wrong?

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