Simple Bar Code Reader using a Raspberry Pi

Reading Bar Codes with the Raspberry Pi

Installation 

Install OpenCV
sudo apt get install python-opencv libopencv-dev 
You might find it is already installed.

Install Python bindings 

pip3 install opencv-python 

Install additional libraries 

sudo apt-get install libcblas-dev 
sudo apt-get install libhdf5-dev -y
 && sudo apt-get install libhdf5-serial-dev -y 
 && sudo apt-get install libatlas-base-dev -y
 && sudo apt-get install libjasper-dev -y
 && sudo apt-get install libqtgui4 -y
 && sudo apt-get install libqt4-test -y 

Install ZBAR and PYZBAR 

According to one of the references, zbar does not have a python3 version, however the pyzbar works with Python3.
sudo apt-get install libzbar0 
pip3 install pyzbar 
Remember to use pip3 not pip to install pyzbar for Python3 (your installation may vary - pip defaults to Python2 in most installations).

Test program 

from pyzbar import pyzbar

import cv2

imagefile="/home/pi/Documents/Python/barcodetest.jpg"

print(imagefile)

# load the input image

image = cv2.imread(imagefile)

# find the barcodes in the image and decode each of the barcodes

barcodes = pyzbar.decode(image)

# loop over the detected barcodes

for barcode in barcodes:

    # extract the bounding box location of the barcode and draw the

    # bounding box surrounding the barcode on the image

    (x, y, w, h) = barcode.rect

    cv2.rectangle(image, (x, y), (x + w, y + h), (0, 0, 255), 2)

    # the barcode data is a bytes object so if we want to draw it on

    # our output image we need to convert it to a string first

    barcodeData = barcode.data.decode("utf-8")

    barcodeType = barcode.type

    # draw the barcode data and barcode type on the image

    text = "{} ({})".format(barcodeData, barcodeType)

    cv2.putText(image, text, (x, y - 10), cv2.FONT_HERSHEY_SIMPLEX,

        0.5, (0, 0, 255), 2)

    # print the barcode type and data to the terminal

    print("[INFO] Found {} barcode: {}".format(barcodeType, barcodeData))

# show the output image

cv2.imshow("Image", image)

cv2.waitKey(0)

Troubleshooting

There may be issues with the version of numpy installed by the above.

If you getr an import error, remove the installed version of numpy and replace it with one from the Raspbian repository.

pip3 uninstall numpy  # remove previously installed version
apt install python3-numpy

https://numpy.org/devdocs/user/troubleshooting-importerror.html

References 

https://www.pyimagesearch.com/2018/05/21/an-opencv-barcode-and-qr-code-scanner-with-zbar/
https://www.learnopencv.com/barcode-and-qr-code-scanner-using-zbar-and-opencv/
https://www.raspberrypi.org/forums/viewtopic.php?p=848265 
https://stackoverflow.com/questions/19876079/cannot-find-module-cv2-when-using-opencv