OCR for Scanned Documents
Tesseract via pytesseract, image preprocessing, and accuracy improvement.
When OCR Is Necessary
Not all documents are digital-native PDFs. Scanned documents, photographs of text, handwritten notes, and image-based PDFs require Optical Character Recognition (OCR) to extract text.
OCR converts pixel images of text into machine-readable characters. Two leading Python libraries: pytesseract (Google Tesseract) and EasyOCR (deep learning, multilingual).
pytesseract Basics
pytesseract is a Python wrapper around Google's Tesseract OCR engine. Install Tesseract first (OS-level), then pip install pytesseract Pillow.
import pytesseract
from PIL import Image
# Simple text extraction
image = Image.open('scanned_document.png')
text = pytesseract.image_to_string(image)
print(text)
# Specify language (default: English)
text_fr = pytesseract.image_to_string(
Image.open('french_doc.png'),
lang='fra'
)
# Get detailed output with bounding boxes
data = pytesseract.image_to_data(
image,
output_type=pytesseract.Output.DICT
)
for i, word in enumerate(data['text']):
if word.strip():
conf = data['conf'][i]
print(f'Word: {word!r:20} Confidence: {conf}')All lessons in this course
- PDF Parsing with PyMuPDF and pdfplumber
- OCR for Scanned Documents
- Multi-Document Q&A Agents
- Document Classification and Routing