Python - Detect a QR code from an image and crop using OpenCV

Question

I\'m working on a project using Python(3.7) and OpenCV in which I have an Image(captured using the camera) of a document with a QR code placed on it.

This QR code ha

Answer 1

I got the width and height data using points and compare it with the qr_data size. Then cropped the QR according to needed.

import cv2
import math  

image = cv2.imread('/ur/image/directory/qr.jpg')

qrCodeDetector = cv2.QRCodeDetector()
decodedText, points, _ = qrCodeDetector.detectAndDecode(image)
qr_data = decodedText.split(',')
qr_size = qr_data[0]
top = qr_data[1]
right = qr_data[2]
bottom = qr_data[3]
left = qr_data[4]

if points is not None:
    pts = len(points)
    print(pts)
    for i in range(pts):
        nextPointIndex = (i+1) % pts
        cv2.line(image, tuple(points[i][0]), tuple(points[nextPointIndex][0]), (255,0,0), 5)
        print(points[i][0])

    width = int(math.sqrt((points[0][0][0]-points[1][0][0])**2 + (points[0][0][1]-points[1][0][1])**2))
    height = int(math.sqrt((points[1][0][0]-points[2][0][0])**2 + (points[1][0][1]-points[2][0][1])**2))

    # Compare the size
    if(width==qr_data[0] and height==qr_data[0]):
        print("Sizes are equal")
    else:
        print("Width and height  " + str(width) + "x" +  str(height) + "  not equal to " 
        + str(qr_data[0]) + "x" + str(qr_data[0]))

    # Add the extension values to points and crop
    y = int(points[0][0][1]) - int(qr_data[1])
    x = int(points[0][0][0]) - int(qr_data[4])
    roi = image[y:y+height + int(qr_data[3]), x:x+width + int(qr_data[2])]
    print(decodedText)    
    cv2.imshow("Image", image)
    cv2.imshow("Crop", roi)
    cv2.waitKey(0)
    cv2.destroyAllWindows()
else:
    print("QR code not detected")

Result: