Binary image B2
Binary image Y2
I think these images are quite simple and clear. Still pytesseract does not work. I really wonder why.
Here is my code
from pytesseract import pytesseract as tesseract
import cv2 as cv
binary = cv.imread(filepath)
lang = 'eng'
config = 'tessedit_char_whitelist=RGB123'
print(tesseract.image_to_string(binary, lang=lang, config=config))
The output is just blank string.
To Dennlinger's point, I would definitely rotate it before sending it through PyTess. PyTess should rotate it automatically though. Should.
Alternatively, I see in your configuration that you have white listed "RGB123" which, correct me if I'm wrong, may mean that PyTess is mainly looking for those specific numbers and characters.
I'd try changing your configuration by omiting that configuration so that it can pick up the "Y" in there.
I'm learning OCR using PyTesser and Tesseract. As the first milestone, I want to write a tool to recognize captcha that simply consists of some digits. I read some tutorials and wrote such a test program.
from pytesser.pytesser import *
from PIL import Image, ImageFilter, ImageEnhance
im = Image.open("test.tiff")
im = im.filter(ImageFilter.MedianFilter())
enhancer = ImageEnhance.Contrast(im)
im = enhancer.enhance(2)
im = im.convert('1')
text = image_to_string(im)
print "text={}".format(text)
I tested my code with the image below. But the result is 2(T?770. And I've tested some other similar images as well, in 80% case the results are incorrect.
I'm not familiar with imaging processing. I've two questions here:
Is it possible to tell PyTesser to guess digits only?
I think the image is quite easy for human to read. If it is so difficult for PyTesser to read digits only image, is there any alternatives can do a better OCR?
Any hints are very appreciated.
I think your code is quite okay. It can recognize 207770. The problem is at pytesser installation. The Tesseract in pytesser is out-of-date. You'd download a most recent version and overwrite corresponding files. You'd also edit pytesser.py and change
tesseract_exe_name = 'tesseract'
to
import os.path
tesseract_exe_name = os.path.join(os.path.dirname(__file__), 'tesseract')
I'm having difficulty making ReportLab render Chinese Characters. From everything I've looked up people are saying that it is probably a font problem but I've used a lot of different fonts and it doesn't even seem to be using them at all. The Chinese characters always just come out as black squares. Below is some sample code of what I have.
# -*- coding: utf8 -*-
from reportlab.lib.pagesizes import letter
from reportlab.pdfbase.ttfonts import TTFont
from io import BytesIO
pdfmetrics.registerFont(TTFont('Arial', 'arial.ttf', 'UTF-8'))
buffer = BytesIO()
doc = SimpleDocTemplate(buffer,
rightMargin=inch*0.5, # 1/2 Inch
leftMargin=inch*0.5, # 1/2 Inch
bottomMargin=0,
topMargin=inch*0.375, # 3/8 Inch
pagesize=letter)
# Get Styles
styles = getSampleStyleSheet()
# Custom Style
styles.add(ParagraphStyle(name='Address', font='Arial', fontSize=8))
elements = []
elements.append(Paragraph(u'6905\u897f\u963f\u79d1\u8857\uff0c\u5927\u53a6\uff03\u5927', styles['Address']))
doc.build(elements)
# Get the value of the BytesIO buffer and write it to the response.
pdf = buffer.getvalue()
buffer.close()
return pdf
I'm using an arial.ttf font found on my Ubuntu 12.04 installation in the fonts folder. I have also tried other fonts installed on this machine and all have exactly the same look even on the numbers and none of the Chinese characters are anything other than black squares.
Am I registering fonts wrong if even the numbers at the beginning aren't printing correctly? What could be causing the black squares?
Solved it. Turns out in your ParagraphStyle it needs to be fontName="Arial" not font="Arial" but I did learn some other tricks of getting it to work in other ways below.
styles.add(ParagraphStyle(name='Address', fontName='Arial')
After doing some digging I've learned a few things that I hope helps someone else in this situation. When you add the tags inside of your Paragraph around the Unicode text and set it explicitly to a font it will work.
elements.append(Paragraph(u'<font name="Arial">6905\u897f\u963f\u79d1\u8857\uff0c\u5927\u53a6\uff03\u5927</font>', styles['Address']))
This fixes the problem at least for Paragraphs with various fonts.
Again this code will work.
Choose the fonts that supports Chinese characters.
In Ubuntu, I choose "AR PL UMing CN" for example.
My code snippets:
# -*- coding: utf-8 -*-
...
pdfmetrics.registerFont(TTFont('AR PL UMing CN', 'uming.ttc'))
styles = getSampleStyleSheet()
...
styles.add(ParagraphStyle(name='Chinese', fontName='AR PL UMing CN', fontSize=20))
elements=[]
elements.append(Paragraph("成”, styles['Chinese']))
doc.build(elements)
...
I can even change to Chinese editor and type in the character straight off. Hope this helps.
This question already has answers here:
How to extract text from a PDF file?
(33 answers)
Closed 2 months ago.
Problem
I'm trying to determine what type a document is (e.g. pleading, correspondence, subpoena, etc) by searching through its text, preferably using python. All PDFs are searchable, but I haven't found a solution to parsing it with python and applying a script to search it (short of converting it to a text file first, but that could be resource-intensive for n documents).
What I've done so far
I've looked into pypdf, pdfminer, adobe pdf documentation, and any questions here I could find (though none seemed to directly solve this issue). PDFminer seems to have the most potential, but after reading through the documentation I'm not even sure where to begin.
Is there a simple, effective method for reading PDF text, either by page, line, or the entire document? Or any other workarounds?
This is called PDF mining, and is very hard because:
PDF is a document format designed to be printed, not to be parsed. Inside a PDF document,
text is in no particular order (unless order is important for printing), most of the time
the original text structure is lost (letters may not be grouped
as words and words may not be grouped in sentences, and the order they are placed in
the paper is often random).
There are tons of software generating PDFs, many are defective.
Tools like PDFminer use heuristics to group letters and words again based on their position in the page. I agree, the interface is pretty low level, but it makes more sense when you know
what problem they are trying to solve (in the end, what matters is choosing how close from the neighbors a letter/word/line has to be in order to be considered part of a paragraph).
An expensive alternative (in terms of time/computer power) is generating images for each page and feeding them to OCR, may be worth a try if you have a very good OCR.
So my answer is no, there is no such thing as a simple, effective method for extracting text from PDF files - if your documents have a known structure, you can fine-tune the rules and get good results, but it is always a gambling.
I would really like to be proven wrong.
[update]
The answer has not changed but recently I was involved with two projects: one of them is using computer vision in order to extract data from scanned hospital forms. The other extracts data from court records. What I learned is:
Computer vision is at reach of mere mortals in 2018. If you have a good sample of already classified documents you can use OpenCV or SciKit-Image in order to extract features and train a machine learning classifier to determine what type a document is.
If the PDF you are analyzing is "searchable", you can get very far extracting all the text using a software like pdftotext and a Bayesian filter (same kind of algorithm used to classify SPAM).
So there is no reliable and effective method for extracting text from PDF files but you may not need one in order to solve the problem at hand (document type classification).
I am totally a green hand, but this script works for me:
# import packages
import PyPDF2
import re
# open the pdf file
reader = PyPDF2.PdfReader("test.pdf")
# get number of pages
num_pages = len(reader.pages)
# define key terms
string = "Social"
# extract text and do the search
for page in reader.pages:
rext = page.extract_text()
# print(text)
res_search = re.search(string, text)
print(res_search)
I've written extensive systems for the company I work for to convert PDF's into data for processing (invoices, settlements, scanned tickets, etc.), and #Paulo Scardine is correct--there is no completely reliable and easy way to do this. That said, the fastest, most reliable, and least-intensive way is to use pdftotext, part of the xpdf set of tools. This tool will quickly convert searchable PDF's to a text file, which you can read and parse with Python. Hint: Use the -layout argument. And by the way, not all PDF's are searchable, only those that contain text. Some PDF's contain only images with no text at all.
I recently started using ScraperWiki to do what you described.
Here's an example of using ScraperWiki to extract PDF data.
The scraperwiki.pdftoxml() function returns an XML structure.
You can then use BeautifulSoup to parse that into a navigatable tree.
Here's my code for -
import scraperwiki, urllib2
from bs4 import BeautifulSoup
def send_Request(url):
#Get content, regardless of whether an HTML, XML or PDF file
pageContent = urllib2.urlopen(url)
return pageContent
def process_PDF(fileLocation):
#Use this to get PDF, covert to XML
pdfToProcess = send_Request(fileLocation)
pdfToObject = scraperwiki.pdftoxml(pdfToProcess.read())
return pdfToObject
def parse_HTML_tree(contentToParse):
#returns a navigatibale tree, which you can iterate through
soup = BeautifulSoup(contentToParse)
return soup
pdf = process_PDF('http://greenteapress.com/thinkstats/thinkstats.pdf')
pdfToSoup = parse_HTML_tree(pdf)
soupToArray = pdfToSoup.findAll('text')
for line in soupToArray:
print line
This code is going to print a whole, big ugly pile of <text> tags.
Each page is separated with a </page>, if that's any consolation.
If you want the content inside the <text> tags, which might include headings wrapped in <b> for example, use line.contents
If you only want each line of text, not including tags, use line.getText()
It's messy, and painful, but this will work for searchable PDF docs. So far I've found this to be accurate, but painful.
Here is the solution that I found it comfortable for this issue. In the text variable you get the text from PDF in order to search in it. But I have kept also the idea of spiting the text in keywords as I found on this website: https://medium.com/#rqaiserr/how-to-convert-pdfs-into-searchable-key-words-with-python-85aab86c544f from were I took this solution, although making nltk was not very straightforward, it might be useful for further purposes:
import PyPDF2
import textract
from nltk.tokenize import word_tokenize
from nltk.corpus import stopwords
def searchInPDF(filename, key):
occurrences = 0
pdfFileObj = open(filename,'rb')
pdfReader = PyPDF2.PdfFileReader(pdfFileObj)
num_pages = pdfReader.numPages
count = 0
text = ""
while count < num_pages:
pageObj = pdfReader.getPage(count)
count +=1
text += pageObj.extractText()
if text != "":
text = text
else:
text = textract.process(filename, method='tesseract', language='eng')
tokens = word_tokenize(text)
punctuation = ['(',')',';',':','[',']',',']
stop_words = stopwords.words('english')
keywords = [word for word in tokens if not word in stop_words and not word in punctuation]
for k in keywords:
if key == k: occurrences+=1
return occurrences
pdf_filename = '/home/florin/Downloads/python.pdf'
search_for = 'string'
print searchInPDF (pdf_filename,search_for)
I agree with #Paulo PDF data-mining is a huge pain. But you might have success with pdftotext which is part of the Xpdf suite freely available here:
http://www.foolabs.com/xpdf/download.html
This should be sufficient for your purpose if you are just looking for single keywords.
pdftotext is a command line utility, but very straightforward to use. It will give you text files, which you may find easier to work with.
If you are on bash, There is a nice tool called pdfgrep,
Since, This is in apt repository, You can install this with:
sudo apt install pdfgrep
It had served my requirements well.
Trying to pick through PDFs for keywords is not an easy thing to do. I tried to use the pdfminer library with very limited success. It’s basically because PDFs are pandemonium incarnate when it comes to structure. Everything in a PDF can stand on its own or be a part of a horizontal or vertical section, backwards or forwards. Pdfminer was having issues translating one page, not recognizing the font, so I tried another direction — optical character recognition of the document. That worked out almost perfectly.
Wand converts all the separate pages in the PDF into image blobs, then you run OCR over the image blobs. What I have as a BytesIO object is the content of the PDF file from the web request. BytesIO is a streaming object that simulates a file load as if the object was coming off of disk, which wand requires as the file parameter. This allows you to just take the data in memory instead of having to save the file to disk first and then load it.
Here’s a very basic code block that should be able to get you going. I can envision various functions that would loop through different URL / files, different keyword searches for each file, and different actions to take, possibly even per keyword and file.
# http://docs.wand-py.org/en/0.5.9/
# http://www.imagemagick.org/script/formats.php
# brew install freetype imagemagick
# brew install PIL
# brew install tesseract
# pip3 install wand
# pip3 install pyocr
import pyocr.builders
import requests
from io import BytesIO
from PIL import Image as PI
from wand.image import Image
if __name__ == '__main__':
pdf_url = 'https://www.vbgov.com/government/departments/city-clerk/city-council/Documents/CurrentBriefAgenda.pdf'
req = requests.get(pdf_url)
content_type = req.headers['Content-Type']
modified_date = req.headers['Last-Modified']
content_buffer = BytesIO(req.content)
search_text = 'tourism investment program'
if content_type == 'application/pdf':
tool = pyocr.get_available_tools()[0]
lang = 'eng' if tool.get_available_languages().index('eng') >= 0 else None
image_pdf = Image(file=content_buffer, format='pdf', resolution=600)
image_jpeg = image_pdf.convert('jpeg')
for img in image_jpeg.sequence:
img_page = Image(image=img)
txt = tool.image_to_string(
PI.open(BytesIO(img_page.make_blob('jpeg'))),
lang=lang,
builder=pyocr.builders.TextBuilder()
)
if search_text in txt.lower():
print('Alert! {} {} {}'.format(search_text, txt.lower().find(search_text),
modified_date))
req.close()
This answer follows #Emma Yu's:
If you want to print out all the matches of a string pattern on every page.
(Note that Emma's code prints a match per page):
import PyPDF2
import re
pattern = input("Enter string pattern to search: ")
fileName = input("Enter file path and name: ")
object = PyPDF2.PdfFileReader(fileName)
numPages = object.getNumPages()
for i in range(0, numPages):
pageObj = object.getPage(i)
text = pageObj.extractText()
for match in re.finditer(pattern, text):
print(f'Page no: {i} | Match: {match}')
A version using PyMuPDF. I find it to be more robust than PyPDF2.
import fitz
import re
# load document
doc = fitz.open(filename)
# define keyterms
String = "hours"
# get text, search for string and print count on page.
for page in doc:
text = ''
text += page.getText()
print(f'count on page {page.number +1} is: {len(re.findall(String, text))}')
Example with pdfminer.six
from pdfminer import high_level
with open('file.pdf', 'rb') as f:
text = high_level.extract_text(f)
print(text)
Compared to PyPDF2, it can work with cyrillic