Problem Polish plate (eu) with the letter I in the third position

[rafbi77]

Hello. I have a problem with Polish number plates with the letter I in the 3rd position. I use in openalpr.conf settings ocr_language = leu. Examples: 1. alpr -c eu --config /home/pi/openalpr.conf --clock /home/pi/IMG_20180801_180432.jpg Total Time to process image: 441.7ms. plate0: 8 results -- Processing Time = 239.964ms.

• KL4228C confidence: 90.9312
• KL422BC confidence: 82.11
• KL4Z28C confidence: 81.5972
• KL42Z8C confidence: 81.0869
• KL4Z2BC confidence: 72.776
• KL42ZBC confidence: 72.2657
• KL4ZZ8C confidence: 71.753
• KL4ZZBC confidence: 62.931

2. alpr -c eu --config /home/pi/openalpr.conf --clock /home/pi/IMG_20180801_181042.jpg Total Time to process image: 396.535ms. plate0: 10 results -- Processing Time = 203.787ms.

   • SC8995 confidence: 81.3158
   • SC895 confidence: 80.4155
   • SC84995 confidence: 79.8447
   • SC8495 confidence: 78.9443
   • S8995 confidence: 77.532
   • S84995 confidence: 76.0608
   • S8495 confidence: 75.1605
   • SCB995 confidence: 72.2444
   • SC899S confidence: 72.0792
   • SCB95 confidence: 71.344

3. alpr -c eu --config /home/pi/openalpr.conf --clock /home/pi/IMG_20180801_182437.jpg Total Time to process image: 260.946ms. plate0: 6 results -- Processing Time = 136.325ms.

   • SM97LS confidence: 89.3511
   • 5M97LS confidence: 81.5484
   • SM97L5 confidence: 78.4478
   • M97LS confidence: 77.4218
   • 5M97L5 confidence: 70.6451
   • M97L5 confidence: 66.5184

But with license plates with the letter I in the 2nd position is Ok:

alpr -c eu --config /home/pi/openalpr.conf --clock /home/pi/IMG_20180801_182142.jpg Total Time to process image: 430.729ms. plate0: 10 results -- Processing Time = 296.253ms.

• W033OP confidence: 84.6708
• WI033OP confidence: 83.4689
• W1033OP confidence: 82.464
• W0330P confidence: 82.1501
• WI0330P confidence: 80.9481
• W10330P confidence: 79.9432
• W033O confidence: 79.9352
• WI033O confidence: 78.7332
• W033DP confidence: 77.7499
• W1033O confidence: 77.7283

All 3 letter prefixes in Poland with the letter I: DMI CLI LBI FMI FZI EPI ESI EWI KLI KMI KWI WCI WLI WPI WSI RMI RNI BIA SPI SBI SCI SMI TPI TKI NGI NIL NLI NNI NPI PMI ZBI

[mateok0]

I'm pinching. Do you have an idea for an idea? Did you manage to solve?

[ArturRog]

I'd also like to know if you found any solution!

[rafbi77]

After some time, I came to the conclusion that the reason for incorrect reading is a small verification sticker on the license plate. When we retouch it, the algorithm works good.

alpr -d -c eu --config /home/pi/openalpr.conf --clock /home/pi/mik.jpg Total Time to process image: 312.825ms. plate0: 10 results -- Processing Time = 124.663ms.

• SMI7LS confidence: 89.1368
• SMI97LS confidence: 87.5475
• 5MI7LS confidence: 81.5313
• 5MI97LS confidence: 79.942
• SMI7L5 confidence: 77.2448
• MI7LS confidence: 77.2324
• SMI97L5 confidence: 75.6555
• MI97LS confidence: 75.6431
• 5MI7L5 confidence: 69.6393
• 5MI97L5 confidence: 68.05

Now how to improve it in the code or config?

1. Potential places are binarizewolf.cpp or characteranalysis.cpp?
2. Controlling parameters does not give results: char_analysis_min_pct = 0.35 char_analysis_height_range = 0.15 char_analysis_height_step_size = 0.10 char_analysis_height_num_steps = 5

segmentation_min_speckle_height_percent = 0.2 segmentation_min_box_width_px = 5 segmentation_min_charheight_percent = 0.4 segmentation_max_segment_width_percent_vs_average = 2.0