python extract text from image or pdf

John D K -

In this post:

Python's binding pytesseract for tesserct-ocr is extracting text from image or PDF with great success:

str = pytesseract.image_to_string(file, lang='eng')

You can watch video demonstration of extraction from image and then from PDF files:

You could find interesting this summary python post: Python useful tips and reference project

Extract text from image

Below you can find simple python 3 example of reading image file and outputting the text to the console. You will need to import pil and pytesseract:

from PIL import Image
import pytesseract

file = Image.open("/home/user/sample.png")
str = pytesseract.image_to_string(file, lang='eng')

print(str)

You need to add language parameter like:

  • fra - French
  • eng - English
  • spa - Spanish
  • rus - Russian
  • deu - German

Here you can find list of other languages:

tesseract languages

Required Libraries

In order the code above to work you may need(unless you have them) the following additional packages. You need to run this in your terminal or pip console:

  • install tesseract-ocr:
sudo apt-get install tesseract-ocr
  • install pill and pytesseract(used for connection to tesseract-ocr):
pip install pillow
pip install pytesseract

Python OCR(Optical Character Recognition) for PDF

OCR or text extraction from PDF is divided in several steps:

  • open the PDF file with wand / imagemagick
  • convert the PDF to images
  • read images one by one and extract the text with pytesseract / tesserct-ocr
import io
from PIL import Image
import pytesseract
from wand.image import Image as wi

pdfFile = wi(filename = ""/home/user/sample.pdf"", resolution = 300)
image = pdfFile.convert('jpeg')

imageBlobs = []

for img in image.sequence:
	imgPage = wi(image = img)
	imageBlobs.append(imgPage.make_blob('jpeg'))

extract = []

for imgBlob in imageBlobs:
	image = Image.open(io.BytesIO(imgBlob))
	text = pytesseract.image_to_string(image, lang = 'eng')
	extract.append(text)

print(extract)

Required Libraries

Only for PDF example you need to install imagemagick binding of python 3:

pip install wand

Python OCR multiple images in folder:

If you have more than one image you can iterate over all and extract the text by os.walk. Then open image by image and extract the text:

from PIL import Image
import pytesseract
import os

indir = r'/home/user/photos/'
for root, dirs, filenames in os.walk(indir):
    for filename in filenames:
        print('#####################################' + filename + '#####################################')
        im = Image.open(indir + filename)
        text = pytesseract.image_to_string(im, lang='eng')
        print(text)

How to improve the OCR results

Use white color themes (dark text on white background)

Below you can see two examples of a good and a bad image containing one and the same text but giving completely different results:

The good version is and the ouput is:

Unsupported Operating System

You are running Workbench on an unsupported operating system. While it
may work for you just fine, it wasn't designed to run on your platform.
Please keep this in mind if you run into problems.

(© Don't show this message again

OK

While the bad example is here and the result is:

De ee ec Ec
Ses en anche eu

it may work for you just fine, it wasn't designed to run on your platform.
ee oe Sn ere ces

De ee

ir

The lighter version is performing much better in comparison to the dark one.

Scale the image to the optimal size

Depending on the image you can increase the size of the image: double the width and height. This could improve the OCR recognition by PyTesseract significantly for some images. There is a really nice and comprehensive article here:

Improve OCR Accuracy With Advanced Image Preprocessing

In short the practical tips are:

  • remove noise and useless information
  • increase contract
  • choose the right size
  • get the best possible image quality