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Best way to check the readibility of QR codes (lemmy.world)
submitted 6 months ago by to c/programming@programming.dev
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I am writing something that needs to verify the practical readability of qr codes which has been painted over.

First thing that comes to mind is to apply Gaussian blur on the image and check if it is readable. Then I could get a "readability score" by doing binary search between blur strengths range [0, n].

I also may do the same with noise, not sure if I should.

Would appreciate if somebody with more knowledge of QR codes help me

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[–] 3 points 6 months ago (3 children)

Look up error correction levels of Qr code. And if you want to be sure, add your own bits in rgb.

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  • [–] [S] 4 points 6 months ago* (2 children)

    I just did.

    I will block (or discourage) writing on timing bits and stuff and limit writes on format bits. It seems that I need to implement my own QR functions to properly check every feature manually

    I am also in the process of manually calculating a QR code and drawing it on paper to understand the format better. (pretty fun activity ngl)

    Btw the thing I am building is an app that would help manually create qr code art.

    RGB is not feasible because the aim of the app is to be a monochrome first QR art creator.

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  • [–] 2 points 6 months ago

    The art may be monochrome but the readers interpreting the QR (the part you are supposed to be testing) are almost certainly RGB. If you are not testing from the point of view of a camera reading the image, you are leaving a blind spot, no pun intended, and are not really testing properly.

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