System Information

OpenCV: a3b3a58

Detailed description

Using an image qrcode-kanji_mod.png with a single extra black pixel on specific location breaks detection.

Steps to reproduce

import cv2 as cv
img = cv.imread("qrcode-kanji_mod.png")
detect = cv.QRCodeDetector()
det = detect.detect(img)
print("1:", det)

img = cv.imread("qrcode-kanji_mod.png")
img[-1, 296] = 0
detect = cv.QRCodeDetector()
det = detect.detect(img)
print("2:", det)

1: (True, array([[[  9.,   4.],
        [632.,   4.],
        [632., 628.],
        [  9., 628.]]], dtype=float32))
2: (False, None)

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)