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pythonimage-processingocrpython-tesseract

Pytesseract not working for low resolution images

I am trying to read numbers from an image with 20x10 resolution. I know this question might be a duplicate. I've gone through most of the questions here on stack overflow but none of the answers seems to work for me. Here is the image I am trying to read text from:
enter image description here

Here is the my current code:

import pytesseract as pt
from PIL import Image


pt.pytesseract.tesseract_cmd = r"C:\Program Files\Tesseract-OCR\tesseract.exe"

img = Image.open('foo.PNG')
text = pt.image_to_string(img)
print(text)

?

I am new to pytesseract and image processing. Any suggestion or help will be greatly appreciated.

Solution

  • Actually, I have to say that tesseract is very touchy to play with. According to my experiences, I can easily say that if you -as a human- are not able to read a text clearly, you shouldn't expect tesseract to read it either.

    First of all; to get better results, it is a must to make a good preprocessing. I strongly recommend anyone dealing with tesseract to check their documentation about Improving the quality.

    In your case, problem is about the resolution. Is low resolution a reason for tesseract not to read a text ? Answer is absolutely yes. Documentation says:

    Tesseract works best on images which have a DPI of at least 300 dpi, so it may be beneficial to resize images.

    In here DPI means dots per inch and its suggested lower limit is 300 DPI which is higher than your image. When you resize the image to a higher resolution, for example 10 times bigger:

    enter image description here

    Now even if DPI satisfies, now you are losing the accuracy and getting noises.

    Note: It also doesn't mean that higher resolution means better results. Please check here.

    Note: If you really need to continue on these types of images, you may need to have a look at here. First you get higher resolution and then deblurring operation, this may help to figure it out.