How to Generate and Read Barcodes With Python

When you purchase an item from a store, the parallel black stripes of varying widths on the item you purchase is called barcode. Barcodes are a method of representing data in a visual, machine-readable format. Barcodes are used to store information about products for easy identification and tracking. Various industries use barcodes for inventory management.

Using Python you can generate barcodes, scan and read the content of a barcode.

How to Generate and Customize Barcodes

The following steps show how to generate barcodes using the python-barcode library.

1. Install the Required Library

Open your terminal or command prompt and run the following pip command to install the required library. Ensure you have pip installed on your machine.

 pip install python-barcode
 

2. Import the Required Modules

In your script, include the following import statements to import the modules needed for barcode generation.

 import barcode
from the barcode.writer import ImageWriter
 

Writers handle the generation and saving of barcode images in different formats. The python-barcode library provides different barcode writers. Here you’re going to use the ImageWriter class which renders barcodes as images.

3. Code to Generate Barcode

The python-barcode library offers various barcode formats, such as Code39, Code128, EAN13, and ISBN-10 for generating barcodes.

 def generate_barcode(data, barcode_format, options=None):
    
    barcode_class = barcode.get_barcode_class(barcode_format)
    
    barcode_image = barcode_class(data, writer=ImageWriter())
    
    barcode_image.save("barcode", options=options)
 

The generate_barcode function generates a barcode based on the given data and format (barcode_format) and saves the barcode image to a file, barcode.png. The file extension depends on the writer class you use.

4. Generate and Customize Barcode

To generate a barcode, call the generate_barcode function and pass the required parameters.

 generate_barcode("MakeUseOf", "code128")
 

Writers take several options that allow you to customize barcodes. Customization options include modifying the size, font, color of the barcode, and so on. You can refer to the python-barcode documentation to access the complete list of common writer options.

 
generate_barcode("MakeUseOf", "code128", options={"foreground":"red", 
                                                  "center_text": False, 
                                                  "module_width":0.4, 
                                                  "module_height":20}) 

How to Scan and Decode Barcodes

The following steps show how to scan and decode barcodes using the Python pyzbar library.

1. Install the Required Libraries

To scan and decode barcodes, you need to install the following libraries:

 brew install zbar 
sudo apt-get install libzbar0 
pip install pyzbar opencv-python
 

2. Import the Required Modules

After installing the libraries, add the following import statements to your script to import the necessary modules.

 import cv2
from pyzbar import pyzbar
 

3. Scan Barcodes From Images

To scan barcodes from image files:

1. Load the image using OpenCV’s imread function. This returns an instance of numpy.ndarray.
2. Pass the output array to pyzbar.decode for detection and decoding. You can also pass instances of PIL.Image.

 def scan_barcode_from_image(image_path):
    
    image = cv2.imread(image_path)
    
    barcodes = pyzbar.decode(image)
    
    for barcode in barcodes:
        
        barcode_data = barcode.data.decode("utf-8")
        barcode_type = barcode.type
        print("Barcode Data:", barcode_data)
        print("Barcode Type:", barcode_type)
 

The function takes an image_path parameter, reads the image, decodes any barcodes present in the image, and prints the decoded data and barcode type for each detected barcode.

 scan_barcode_from_image("barcode.png")
> Barcode Data: MakeUseOf
> Barcode Type: CODE128
 

4. Scan Barcodes From Webcam Stream

You can also scan and read barcodes in real-time from a webcam stream with the help of the Python OpenCV library.

 def scan_barcode_from_webcam():
    
    video_capture = cv2.VideoCapture(0)

    while True:
        
        _, frame = video_capture.read()

        
        barcodes = pyzbar.decode(frame)

        
        for barcode in barcodes:
            
            barcode_data = barcode.data.decode("utf-8")
            barcode_type = barcode.type
            print("Barcode Data:", barcode_data)
            print("Barcode Type:", barcode_type)

        
        if cv2.waitKey(1) & 0xFF == ord("q"):
            break

    
    video_capture.release()
    cv2.destroyAllWindows()


scan_barcode_from_webcam()
 

The scan_barcode_from_webcam function continuously captures frames from the webcam, decodes any barcodes present in the frame, extracts information about the barcode, and prints the information. To quit press the letter q on your keyboard.

Generating Barcodes and QR Codes in Python

With Python, generating and reading barcodes becomes accessible and efficient. By following the steps outlined, you can generate a variety of barcodes to suit your needs.

QR codes (Quick Response codes) are two-dimensional barcodes that can be scanned and read by smartphones, tablets, or other devices equipped with a camera and a QR code reader application. Using the Python qrcode library you can generate, scan and read QR Codes efficiently.