How to decode a QR-code image in preferably pure Python

Question

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

User · Accepted Answer

You can try the following steps and code using qrtools:

Create a qrcode file, 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)
```
Decode an existing qrcode file using qrtools
- Install qrtools using sudo 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.'
```

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 PyPNG using pip install pypng for using pyqrcode
In case you have PIL installed, you might get IOError: decoder zip not available. In that case, try uninstalling and reinstalling PIL using:
```
pip uninstall PIL
pip install PIL
```
If that doesn't work, try using Pillow instead
```
pip uninstall PIL
pip install pillow
```

User · Answer

There is a library called BoofCV which claims to better than ZBar and other libraries  Here are the steps to use that  any OS   Pre-requisites   Ensure JDK 14  is installed and set in  PATH pip install pyboof  Class to decode  import os import numpy as np import pyboof as pb  pb init memmap    Optional  class QR Extractor        Src  github com lessthanoptimal PyBoof blob master examples qrcode detect py     def   init   self           self detector   pb FactoryFiducial np uint8  qrcode            def extract self  img path           if not os path isfile img path               print  File not found    img path              return None         image   pb load single band img path  np uint8          self detector detect image          qr codes              for qr in self detector detections              qr codes append                    text   qr message                   points   qr bounds convert tuple                          return qr codes  Usage  qr scanner   QR Extractor   output   qr scanner extract  Your-Image jpg   print output   Tested and works on Python 3 8  Windows  amp  Ubuntu

User · Answer

For Windows using ZBar Pre-requisites   Install ZBar by either   Install Chocolatey and choco install zbar Or use Windows Installer for ZBar   pip install pyzbar  To decode  from PIL import Image from pyzbar import pyzbar  img   Image open  My-Image jpg   output   pyzbar decode img  print output    Alternatively  you can also try using ZBarLight by setting it up as mentioned here  https   pypi org project zbarlight

User · Answer

I m answering only the part of the question about zbar installation   I spent nearly half an hour a few hours 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 whl If Python reports an ImportError  DLL load failed  The specified module could not be found  when doing import 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   If it still does not work  add this    import os os environ  PATH        C   Python27   import zbar    PS  Making it work with Python 3 x is even more difficult  Compile zbar for Python 3 x    PS2  I just tested pyzbar with pip install pyzbar and it s MUCH easier  it works out-of-the-box  the only thing is you need to have VC Redist 2013 files installed   It is also recommended to use this library in this pyimagesearch com article

User · Answer

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

[python] How to decode a QR-code image in (preferably pure) Python?

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