I've got this scanned pdf file. Image based low resolution pdf file. I'm trying to extract the data in it and all options I've tried seem not to work.
Option 1 - using pdfminer
from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter
from pdfminer.converter import TextConverter
from pdfminer.layout import LAParams
from pdfminer.pdfpage import PDFPage
from io import StringIO
def convert_pdf_to_txt(path):
rsrcmgr = PDFResourceManager()
retstr = StringIO()
codec = 'utf-8'
laparams = LAParams()
device = TextConverter(rsrcmgr, retstr, laparams=laparams)
fp = open(path, 'rb')
interpreter = PDFPageInterpreter(rsrcmgr, device)
password = ""
maxpages = 0
caching = True
pagenos=set()
for page in PDFPage.get_pages(fp, pagenos, maxpages=maxpages, password=password,caching=caching, check_extractable=True):
interpreter.process_page(page)
text = retstr.getvalue()
fp.close()
device.close()
retstr.close()
return text
Option 2 - using tika
from tika import parser # pip install tika
raw = parser.from_file(path)
text=raw['content']
# I don't like to use it very much because it often corrupts the file
Option 3 - using pypdf
import PyPDF2
pdf_file = open(path, 'rb')
read_pdf = PyPDF2.PdfFileReader(pdf_file)
number_of_pages = read_pdf.getNumPages()
page = read_pdf.getPage(0)
page_content = page.extractText()
text=page_content.encode('utf-8')
All the options return empty results. I suppose it might be related to the quality of the file. I know we could work on images and increase image characteristics to ease the data extraction (increase image size, work on thresholds, etc, you can do a lot of stuff with PIL). Is there an efficient way to also do that with pdf files?
In the end I came up with a solution which is not ideal but worked for me using pdfminer and pytesseract:
from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter
from pdfminer.converter import TextConverter
from pdfminer.layout import LAParams
from pdfminer.pdfpage import PDFPage
from io import StringIO
def convert_pdf_image_to_text(file_path):
from pdf2image import convert_from_path
import pytesseract
dpi = 350 # dots per inch
pages = convert_from_path(file_path ,dpi)
text=""
for i in range(len(pages)):
page = pages[i]
a=pytesseract.image_to_string(page)
text=text+a
return text
def convert_pdf_to_txt(path):
rsrcmgr = PDFResourceManager()
retstr = StringIO()
codec = 'utf-8'
laparams = LAParams()
device = TextConverter(rsrcmgr, retstr, laparams=laparams)
fp = open(path, 'rb')
interpreter = PDFPageInterpreter(rsrcmgr, device)
password = ""
maxpages = 0
caching = True
pagenos=set()
for page in PDFPage.get_pages(fp, pagenos, maxpages=maxpages, password=password,caching=caching, check_extractable=True):
interpreter.process_page(page)
text = retstr.getvalue()
fp.close()
device.close()
retstr.close()
# extracting data from image pdfs
if "a" not in text or "A" not in text and extract_image_pdfs==True:
# my pdfs will always have an "a" that's why I use this if sentence above
try:
print('starting to convert to image')
text=convert_pdf_image_to_text(path)
print('finished converting to image')
except:
text="no text"
print("not pdf nor image")
return text