Welcome folks today in this post we will be scanning or reading  qr codes and also generating qr codes in python using opencv and numpy and qrcode library. All the source code of the application is given below.

 

 

 

Get Started

 

 

 

In order to get started you need to install the following libraries

 

pip install qrcode

 

pip install opencv-python

 

pip install numpy

 

After installing all these libraries we need to create an app.py file and copy paste the following code

 

First of all we will be generating simple qr codes using qrcode library and numpy

 

app.py

 

import qrcode
# example data
data = "https://codingshiksha.com"
# output file name
filename = "codingshiksha.png"
# generate qr code
img = qrcode.make(data)
# save img to a file
img.save(filename)

 

 

Simply we are importing the qrcode library and then we are generating the simple qr code containing the website url codingshiksha.com and we have given the output file name as codingshiksha.png so when you run the python script as shown below

 

python app.py

 

You will see the qr code image being created as shown below

 

 

 

 

 

 

 

You can even make colored qr codes having custom border as well as shown below in the example

 

app.py

 

import qrcode
import numpy as np
# data to encode
data = "https://www.codingshiksha.com"
# instantiate QRCode object
qr = qrcode.QRCode(version=1, box_size=10, border=4)
# add data to the QR code
qr.add_data(data)
# compile the data into a QR code array
qr.make()
# print the image shape
print("The shape of the QR image:", np.array(qr.get_matrix()).shape)
# transfer the array into an actual image
img = qr.make_image(fill_color="white", back_color="red")
# save it to a file
img.save("codingshiksha.png")

 

 

Now this will be a red colored qr code as shown below when you run it

 

 

 

 

Reading QR Codes

 

 

Now we will look at how to read the data which is contained inside the qr codes as shown below in the example

 

app.py

 

import cv2
# initalize the cam
cap = cv2.VideoCapture(0)
# initialize the cv2 QRCode detector
detector = cv2.QRCodeDetector()
while True:
    _, img = cap.read()
    # detect and decode
    data, bbox, _ = detector.detectAndDecode(img)
    # check if there is a QRCode in the image
    if bbox is not None:
        # display the image with lines
        for i in range(len(bbox)):
            # draw all lines
            cv2.line(img, tuple(bbox[i][0]), tuple(bbox[(i+1) % len(bbox)][0]), color=(255, 0, 0), thickness=2)
        if data:
            print("[+] QR Code detected, data:", data)
    # display the result
    cv2.imshow("img", img)    
    if cv2.waitKey(1) == ord("q"):
        break
cap.release()
cv2.destroyAllWindows()

 

 

Here we are using the python-opencv library to read the data of qr code as shown below