python - pytesseract using tesseract 4.0 numbers only not working

15
votes

Any one tried to get numbers only calling the latest version of tesseract 4.0 in python?

The below worked in 3.05 but still returns characters in 4.0, I tried removing all config files but the digits file and still didn't work; any help would be great:

im is an image of a date, black text white background:

import pytesseract
im =  imageOfDate
im = pytesseract.image_to_string(im, config='outputbase digits')
print(im)
4
pythontesseract
Add image to the question for answerers to see your problem. – thewaywewere
I went with stackoverflow.com/questions/9413216/… instead. – Cees Timmerman
@CuriousGeorge: Did you find a solution to your upgrade problem? – Jarl
Upgrading to v4.1.1 did not help me properly. I also had to download the tessdata_fast version of the trainddata files. I am attaching a detailed shell script to install 4.1.1 from the source. – Aritra Roy Gosthipaty

4 Answers

15
votes

You can specify the numbers in the tessedit_char_whitelist as below as a config option.

ocr_result = pytesseract.image_to_string(image, lang='eng', boxes=False, \
           config='--psm 10 --oem 3 -c tessedit_char_whitelist=0123456789')

Hope this help.

11
votes

Using tessedit_char_whitelist flags with pytesseract did not work for me. However, one workaround is to use a flag that works, which is config='digits':

import pytesseract
text = pytesseract.image_to_string(pixels, config='digits')

where pixels is a numpy array of your image (PIL image should also work). This should force your pytesseract into returning only digits. Now, to customize what it returns, find your digits configuration file, on Windows mine was located here:

C:\Program Files (x86)\Tesseract-OCR\tessdata\configs

Open the digits file and add whatever characters you want. After saving and running pytesseract, it should return only those customized characters.

4
votes

You can specify the numbers in the tessedit_char_whitelist as below as a config option.

ocr_result = pytesseract.image_to_string(image, lang='eng',config='--psm 10 --oem 3 -c tessedit_char_whitelist=0123456789')
3
votes

As you can see in this GitHub issue, the blacklist and whitelist doesn't work with tesseract version 4.0.

There are 3 possible solutions for this problem, as I described in this blog article:

  1. Update tesseract to version > 4.1
  2. Use the legacy mode as described in the answer from @thewaywewere

  3. Create a python function which uses a simple regex to extract all numbers:

    def replace_chars(text):
    list_of_numbers = re.findall(r'\d+', text)
    result_number = ''.join(list_of_numbers)
    return result_number

result_number = pytesseract.image_to_string(im)