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Best way to check the readibility of QR codes (lemmy.world)
submitted 3 months ago by yogurtwrong@lemmy.world 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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[-] benjirenji@slrpnk.net 4 points 3 months ago

Without knowing the usecase too much you need vary the following variables:

  • contrast (simulate colors and different lighting conditions)
  • shadows
  • blur
  • viewing angles (perspective distortion)
  • occlusions
  • different QR code versions (v1, v5, v20 etc.)
  • noise (introduced by camera gain)
  • camera lens distortion

Maybe not all is relevant to your usecase, but these are the main challenges.

this post was submitted on 10 May 2026
19 points (95.2% liked)

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