使用python从PDF提取扫描页面

Question

I have a lot of PDF files, which are basically scanned documents so every page is one scanned image. I want to perform OCR and extract text from those files. I have tried pytesseract but it does not perform OCR directly on pdf files so as a work around, I want to extract the images from PDF files, save them in directory and then perform OCR using pytesseract on those images directly. Is there any way in python to extract scanned images from pdf files? or is there any way to perform OCR directly on pdf files?

Answer 1

This question has been addressed in previous Stack Overflow Posts.

Converting PDF to images automatically
Converting a PDF to a series of images with Python

Here is a script that may be helpful: https://nedbatchelder.com/blog/200712/extracting_jpgs_from_pdfs.html

Another method: https://www.daniweb.com/programming/software-development/threads/427722/convert-pdf-to-image-with-pythonmagick

Please check previous posts before asking a question.

EDIT:

Including working script for future reference. Program works for Python3.6 on Windows:

# coding=utf-8
# Extract jpg's from pdf's. Quick and dirty.

import sys

with open("Link/To/PDF/File.pdf", "rb") as file:
    pdf = file.read()

startmark = b"\xff\xd8"
startfix = 0
endmark = b"\xff\xd9"
endfix = 2
i = 0

njpg = 0
while True:
    istream = pdf.find(b"stream", i)
    if istream < 0:
        break
    istart = pdf.find(startmark, istream, istream + 20)
    if istart < 0:
        i = istream + 20
        continue
    iend = pdf.find(b"endstream", istart)
    if iend < 0:
        raise Exception("Didn't find end of stream!")
    iend = pdf.find(endmark, iend - 20)
    if iend < 0:
        raise Exception("Didn't find end of JPG!")

    istart += startfix
    iend += endfix
    print("JPG %d from %d to %d" % (njpg, istart, iend))
    jpg = pdf[istart:iend]
    with open("jpg%d.jpg" % njpg, "wb") as jpgfile:
        jpgfile.write(jpg)

    njpg += 1
    i = iend