kagan94 / automatic-plate-number-recognition-apnr

Simple Automatic Plate Number Recognition script (APNR)

Simple script to detect and recognize plate number (Automatic Plate Number Recognition - APNR)

Link to the .pdf report

Steps:

1. Load image

2. Apply blur filter (to remove noise)

3. Convert blurred image to grayscale

4. Apply Sobel filter to find vertical edges (car plates have a high density of vertical lines)

5. Apply threshold with Ostu’s Binarization (Ostu’s binarization will automatically calculate optimal threshold from image histogram)

   

6. Create a rectangular mask of size of 17x3 and apply “closing” filter to detect plate number more clearly

7. Find and fetch contours of possible plates
8. Validate contours and clear out those, that can't be potential plate numbers
   • Is white color dominant?
   • Rotated not more than 15 degrees
   • In Europe, car plate size: 52x11, aspect 4,7272
   • Define min && max area of plate number
9. After (8), apply dilate filter and threshold to validated contours to get numbers and characters

10)Apply Tesseract to extract plate number as a text. Tesseract is an optical character recognition (OCR) engine sponsored by Google.

Final Results

automatic-plate-number-recognition-apnr's Issues

Compile Error [solved] I have to have my trained data file

I get this error when I try to run it

py -2 main.py

Traceback (most recent call last):
  File "main.py", line 353, in <module>
    process_single_image(images)
  File "main.py", line 305, in process_single_image
    plates, plates_images, mask = find_plate_numbers(img, contours, mask)
  File "main.py", line 263, in find_plate_numbers
    plate_text = image_to_string(plate_im, lang='eng')
  File "D:\Python27\lib\site-packages\pytesseract\pytesseract.py", line 309, in image_to_string
    }[output_type]()
  File "D:\Python27\lib\site-packages\pytesseract\pytesseract.py", line 308, in <lambda>
    Output.STRING: lambda: run_and_get_output(*args),
  File "D:\Python27\lib\site-packages\pytesseract\pytesseract.py", line 218, in run_and_get_output
    run_tesseract(**kwargs)
  File "D:\Python27\lib\site-packages\pytesseract\pytesseract.py", line 194, in run_tesseract
    raise TesseractError(status_code, get_errors(error_string))
pytesseract.pytesseract.TesseractError: (1, u'Tesseract Open Source OCR Engine v3.05.00dev with Leptonica Error opening data file D:\\Tesseract-OCR\\tessdata/eng.traineddata Please make sure the TESSDATA_PREFIX environment variable is set to the parent directory of your "tessdata" directory. Failed loading language \'eng\' Tesseract couldn\'t load any languages! Could not initialize tesseract.')

Which version do you use of all??