问题
TL;DR: I need a way to decode a QR-code from an image file using (preferable pure) Python.
I've got a jpg file with a QR-code which I want to decode using Python. I've found a couple libraries which claim to do this:
PyQRCode (website here) which supposedly can decode qr codes from images by simply providing a path like this:
import sys, qrcode
d = qrcode.Decoder()
if d.decode('out.png'):
print 'result: ' + d.result
else:
print 'error: ' + d.error
So I simply installed it using sudo pip install pyqrcode. The thing I find strange about the example code above however, is that it only imports qrcode (and not pyqrcode though) Since I think qrcode refers to this library which can only generate qr-code images it kind of confused me. So I tried the code above with both pyqrcode and qrcode, but both fail at the second line saying AttributeError: 'module' object has no attribute 'Decoder'. Furthermore, the website refers to Ubuntu 8.10 (which came out more than 6 years ago) and I can't find a public (git or other) repository of it to check the latest commit. So I moved on to the next library:
ZBar (website here) claims to be "an open source software suite for reading bar codes from various sources, such as image files." So I tried installing it on Mac OSX running sudo pip install zbar. This fails with error: command 'cc' failed with exit status 1. I tried to suggestions in the answers to this SO question, but I can't seem to solve it. So I decided to move on again:
QRTools, which according to this blogpost can decode images easily by using the following code:
from qrtools import QR
myCode = QR(filename=u"/home/psutton/Documents/Python/qrcodes/qrcode.png")
if myCode.decode():
print myCode.data
print myCode.data_type
print myCode.data_to_string()
So I tried installing it using sudo pip install qrtools, which can't find anything. I also tried it with python-qrtools, qr-tools, python-qrtools and a couple more combinations, but unfortunately to no avail. I suppose it refers to this repo which says it is based on ZBar (see above). Although I want to run my code on Heroku (and thus prefer a pure Python solution) I successfully installed it on a Linux box (with sudo apt-get install python-qrtools) and tried running it:
from qrtools import QR
c = QR(filename='/home/kramer65/qrcode.jpg')
c.data # prints u'NULL'
c.data_type # prints u'text'
c.data_to_string() # prints '\xef\xbb\xbfNULL' where I expect an int (being `1234567890`)
Although this seems to decode it, It doesn't seem to do it correctly. It furthermore needs ZBar and is thus not pure Python. So I decided to find yet another library.
PyXing (website here) is supposedly a Python port of the popular Java ZXing library, but the initial and only commit is 6 years old and the project has no readme or documentation whatsoever.
For the rest I found a couple qr-encoders (not decoders) and some API endpoints which can decode for you. Since I don't like this service to be dependent on other API endpoints I would want to keep the decoding local though.
So to conclude; would anybody know how I can decode QR-codes from images in (preferable pure) Python? All tips are welcome!
回答1:
You can try the following steps and code using qrtools:
Create a
qrcodefile, if not already existing- I used pyqrcode for doing this, which can be installed using
pip install pyqrcode And then use the code:
>>> import pyqrcode >>> qr = pyqrcode.create("HORN O.K. PLEASE.") >>> qr.png("horn.png", scale=6)
- I used pyqrcode for doing this, which can be installed using
Decode an existing
qrcodefile using qrtools- Install
qrtoolsusingsudo apt-get install python-qrtools Now use the following code within your python prompt
>>> import qrtools >>> qr = qrtools.QR() >>> qr.decode("horn.png") >>> print qr.data u'HORN O.K. PLEASE.'
- Install
Here is the complete code in a single run:
In [2]: import pyqrcode
In [3]: qr = pyqrcode.create("HORN O.K. PLEASE.")
In [4]: qr.png("horn.png", scale=6)
In [5]: import qrtools
In [6]: qr = qrtools.QR()
In [7]: qr.decode("horn.png")
Out[7]: True
In [8]: print qr.data
HORN O.K. PLEASE.
Caveats
- You might need to install
PyPNGusingpip install pypngfor usingpyqrcode In case you have
PILinstalled, you might getIOError: decoder zip not available. In that case, try uninstalling and reinstalling PIL using:pip uninstall PIL pip install PILIf that doesn't work, try using
Pillowinsteadpip uninstall PIL pip install pillow
回答2:
The following code works fine with me:
brew install zbar
pip install pyqrcode
pip install pyzbar
For QR code image creation:
import pyqrcode
qr = pyqrcode.create("test1")
qr.png("test1.png", scale=6)
For QR code decoding:
from PIL import Image
from pyzbar.pyzbar import decode
data = decode(Image.open('test1.png'))
print(data)
that prints the result:
[Decoded(data=b'test1', type='QRCODE', rect=Rect(left=24, top=24, width=126, height=126), polygon=[Point(x=24, y=24), Point(x=24, y=150), Point(x=150, y=150), Point(x=150, y=24)])]
回答3:
I spent nearly half an hour to make it work on Windows + Python 2.7 64-bit, so here are additional notes to the accepted answer:
Download https://github.com/NaturalHistoryMuseum/ZBarWin64/releases/download/v0.10/zbar-0.10-cp27-none-win_amd64.whl
Install it with
pip install zbar-0.10-cp27-none-win_amd64.whlIf Python reports an
ImportError: DLL load failed: The specified module could not be found.when doingimport zbar, then you will just need to install the Visual C++ Redistributable Packages for VS 2013 (I spent a lot of time here, trying to recompile unsuccessfully...)Required too: libzbar64-0.dll must be in a folder which is in the PATH. In my case I copied it to "C:\Python27\libzbar64-0.dll" (which is in the PATH)
Then do
pip install pyqrcode pip install qrtools pip install Pillow
and the code from the main answer should work:
import pyqrcode
qr = pyqrcode.create("HORN O.K. PLEASE.")
qr.png("horn.png", scale=6)
import qrtools
qr = qrtools.QR()
qr.decode("horn.png")
print qr.data
来源：https://stackoverflow.com/questions/27233351/how-to-decode-a-qr-code-image-in-preferably-pure-python