QR code reading in Raspberry Pi - Mini Project: Build & Apply

QR Code Reading on Raspberry Pi

📖 Scenario: You have a Raspberry Pi with a camera attached. You want to read QR codes from images to get useful information like URLs or text.

🎯 Goal: Build a simple Python program that reads a QR code from an image file and prints the decoded text.

📋 What You'll Learn

Use the opencv-python library to load the image.

Use the pyzbar library to detect and decode QR codes.

Create a variable for the image file path.

Print the decoded QR code text.

💡 Why This Matters

🌍 Real World

Reading QR codes is common in many applications like scanning tickets, URLs, or product information using a Raspberry Pi camera.

💼 Career

Understanding how to process images and decode QR codes is useful for jobs in IoT, embedded systems, and computer vision.

1

Set up the image file path

Create a variable called image_path and set it to the string 'qr_code_sample.png' which is the name of the image file containing the QR code.

Raspberry Pi

# Create a variable called image_path with the value 'qr_code_sample.png'
# Your code here

Hint

Use a string to store the file name exactly as 'qr_code_sample.png'.

2

Import libraries and load the image

Import cv2 from opencv-python and decode from pyzbar.pyzbar. Then load the image from image_path using cv2.imread() and store it in a variable called image.

Raspberry Pi

image_path = 'qr_code_sample.png'
# Import cv2 and decode, then load the image into variable image
# Your code here

Hint

Use cv2.imread(image_path) to read the image file.

3

Decode the QR code from the image

Use decode(image) to find QR codes in the image and store the result in a variable called decoded_objects. Then get the first decoded object's data as a string and store it in a variable called qr_text. Use decoded_objects[0].data.decode('utf-8') to decode bytes to string.

Raspberry Pi

import cv2
from pyzbar.pyzbar import decode

image_path = 'qr_code_sample.png'
image = cv2.imread(image_path)
# Decode the QR code and get the text
# Your code here

Hint

Use decode(image) to get a list of decoded objects, then get the first one's data.

4

Print the decoded QR code text

Write a print statement to display the value of the variable qr_text.

Raspberry Pi

import cv2
from pyzbar.pyzbar import decode

image_path = 'qr_code_sample.png'
image = cv2.imread(image_path)
decoded_objects = decode(image)
qr_text = decoded_objects[0].data.decode('utf-8')
# Print the decoded QR code text
# Your code here

Hint

Use print(qr_text) to show the decoded text on the screen.