pytesseract tessedit_char_whitelist not accepting quote

Question

I have started working with pytesserract in python. When i pass it single or double quote in

from PIL import Image
import pytesseract
import numpy as np

tesseract_config = r"""-c tessedit_char_whitelist=0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ#'<>(){};:"""
tesseract_language = "eng"

text = pytesseract.image_to_string(Image.open('res/outc001.jpg'), lang=tesseract_language, config=tesseract_config)
print text

it returns

Traceback (most recent call last):
  File "main.py", line 15, in <module>
    text = pytesseract.image_to_string(Image.open('res/outc001.jpg'), lang=tesseract_language, config=tesseract_config).split('\n')
  File "/usr/local/lib/python2.7/dist-packages/pytesseract/pytesseract.py", line 193, in image_to_string
    return run_and_get_output(image, 'txt', lang, config, nice)
  File "/usr/local/lib/python2.7/dist-packages/pytesseract/pytesseract.py", line 140, in run_and_get_output
    run_tesseract(**kwargs)
  File "/usr/local/lib/python2.7/dist-packages/pytesseract/pytesseract.py", line 106, in run_tesseract
    command += shlex.split(config)
  File "/usr/lib/python2.7/shlex.py", line 279, in split
    return list(lex)
  File "/usr/lib/python2.7/shlex.py", line 269, in next
    token = self.get_token()
  File "/usr/lib/python2.7/shlex.py", line 96, in get_token
    raw = self.read_token()
  File "/usr/lib/python2.7/shlex.py", line 172, in read_token
    raise ValueError, "No closing quotation"
ValueError: No closing quotation

I have been searching for a way to escape single and double quotes and none of them worked.

When i run tesseract as itself with

tesseract res/outc001.jpg tesseract_out/out001 -c "tessedit_char_whitelist=0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ#\'\"<>(){};:"

it works just fine.

What do you mean "when I pass it single or double quote in"? It's not like you're manually calling tesseract with command line arguments; from the looks of the error message you're using `pytesseract.image_to_string`. What are `tesseract_language` and `tesseract_config`? GIve us a [mcve] to work with. — Aran-Fey, Mar 31 '18 at 11:38
text = pytesseract.image_to_string(Image.open('res/outc001.jpg'), lang="eng", config= r"""-c tessedit_char_whitelist=0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ#'<>(){};:""") But the language and config are in a separate file, and I have used every type of escaping quotesi found — Mixony, Mar 31 '18 at 11:44
There's a difference between the text you used in python and the text you used on the command line. You have to escape the quotes. I don't know why you did it on the command line but didn't do it in python. — Aran-Fey, Mar 31 '18 at 11:47
Dupe: https://stackoverflow.com/questions/35817/how-to-escape-os-system-calls — Aran-Fey, Mar 31 '18 at 11:47
I didn't know I have to escape them inside three double quotes, i thought i just put " inside three double quotes. — Mixony, Mar 31 '18 at 12:03

sinecode · Accepted Answer · 2018-03-31T16:05:35.487

Pytesseract uses shlex to separate config arguments.

The escape character for shlex is \, if you want to insert quotes in the shlex.split() function you must escape it with \.

If you want ' only in the whitelist:

tesseract_config = "-c tessedit_char_whitelist=blahblah\\'")

If you want " only:

tesseract_config = '-c tessedit_char_whitelist=blahblah\\"')

If you want both ' and ":

tesseract_config = '''-c tessedit_char_whitelist=blahblah\\'\\"''')

or

tesseract_config = """-c tessedit_char_whitelist=blahblah\\"\\'""")

pytesseract tessedit_char_whitelist not accepting quote

1 Answers1