Extracting tables from a pdf

问题:

I'm trying to get the data from the tables in this PDF. I've tried pdfminer and pypdf with a little luck but I can't really get the data from the tables.

This is what one of the tables looks like:

As you can see, some columns are marked with an 'x'. I'm trying to this table into a list of objects.

This is the code so far, I'm using pdfminer now.

# pdfminer test
from pdfminer.pdfdocument import PDFDocument
from pdfminer.pdfparser import PDFParser
from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter
from pdfminer.pdfdevice import PDFDevice, TagExtractor
from pdfminer.pdfpage import PDFPage, PDFTextExtractionNotAllowed
from pdfminer.converter import XMLConverter, HTMLConverter, TextConverter, PDFPageAggregator
from pdfminer.cmapdb import CMapDB
from pdfminer.layout import LAParams, LTTextBox, LTTextLine, LTFigure, LTImage
from pdfminer.image import ImageWriter
from cStringIO import StringIO
import sys
import os


def pdfToText(path):
    rsrcmgr = PDFResourceManager()
    retstr = StringIO()
    codec = 'utf-8'
    laparams = LAParams()
    device = TextConverter(rsrcmgr, retstr, codec=codec, laparams=laparams)
    fp = file(path, 'rb')
    interpreter = PDFPageInterpreter(rsrcmgr, device)
    password = ''
    maxpages = 0
    caching = True
    pagenos = set()

    records = []
    i = 1
    for page in PDFPage.get_pages(fp, pagenos, maxpages=maxpages, password=password,
                                  caching=caching, check_extractable=True):
        # process page
        interpreter.process_page(page)

        # only select lines from the line containing 'Tool' to the line containing "1 The 'All'"
        lines = retstr.getvalue().splitlines()

        idx = containsSubString(lines, 'Tool')
        lines = lines[idx+1:]
        idx = containsSubString(lines, "1 The 'All'")
        lines = lines[:idx]

        for line in lines:
            records.append(line)
        i += 1

    fp.close()
    device.close()
    retstr.close()

    return records


def containsSubString(list, substring):
    # find a substring in a list item
    for i, s in enumerate(list):
        if substring in s:
            return i
    return -1


# process pdf
fn = '../test1.pdf'
ft = 'test.txt'

text = pdfToText(fn)
outFile = open(ft, 'w')
for i in range(0, len(text)):
    outFile.write(text[i])
outFile.close()

That produces a text file and it gets all of the text but, the x's don't have the spacing preserved. The output looks like this:

The x's are just single spaced in the text document

Right now, I'm just producing text output but my goal is to produce an html document with the data from the tables. I've been searching for OCR examples, and most of them seem confusing or incomplete. I'm open to using C# or any other language that might produce the results I'm looking for.

EDIT: There will be multiple pdfs like this that I need to get the table data from. The headers will be the same for all pdfs (s far as I know).

回答1:

I figured it out, I was going in the wrong direction. What I did was create pngs of each table in the pdf and now I'm processing the images using opencv & python.

回答2:

Give a try to Tabula and if it works use tabula-extractor library (written in ruby) to programatically extract the data.