It seems that I have not installed pyOCR correctly cause I am get an empty list when I do:

import pyocr.builders
pyocr.get_available_tools()

Any ideas?

I have installed pyOCR in an environment through pip:

pip install pyocr --upgrade

EDIT

The following did the trick.

sudo apt-get install tesseract-ocr
sudo apt-get install tesseract-ocr-eng
sudo apt-get install tesseract-ocr-ell