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Dithered QR Codes

andrewt.net

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Re: Dithered QR Codes

#21

Post by OscarCunningham »

hellojomp wrote: post #20

This is really neat! A question I had about QR codes: Let’s say I want to produce a QR code that is as close as possible to an image (let’s say the Nike swoosh logo), if I just added that to the center and added the 3 orientation markers on the corners it wouldn’t be a proper QR code yet, my question is what is the minimal amount of edits I would need to do from that symbol to get a valid QR code? I’m thinking of som…

You could maybe determine this using a SAT solver. You would have to encode the entire QR code specification. I was thinking of doing this to find a minimalist QR code that just had as few black cells as possible.

Re: Dithered QR Codes

#22

Post by ButlerianJihad »

Greetings,

I could not find any LICENSE file or statement on the Codeberg repo. We must therefore conclude that the code is © Copyright 2025-2026, by the author(s), all rights reserved. Crazy to think there are already 3 forkers who've forked you.

Furthermore, let us not forget the patent-holder of QR Codes, DENSO WAVE, and their Frequently Asked Questions:

https://www.qrcode.com/en/faq.html

  Users of QR Code must be careful about deforming the code by overlaying it with an illustration or putting a a design on it. If it is deformed, the QR Code's error correction function is invoked where even a tiny missing or smeared part renders the reading operation impossible, or the response of the operation may become slow.
  If you are contemplating arranging an illustration or design involving a QR Code, please consult with DENSO WAVE about your project beforehand.

Re: Dithered QR Codes

#23

Post by NooneAtAll3 »

I'm not impressed.

the whole technique hinges on qr scanners reading only middle point of the squares

The moment you encounter developer that thought "for redundancy let's sample the whole square" (which is a very natural thought) - it breaks

I kinda expected working the limits of error correction, honestly. Not this blunt circumvention "because it works on my machine"

Re: Dithered QR Codes

#24

Post by jerf »

gblargg wrote: post #17

This reminds me of car safety features, how drivers have become more complacent to offset the benefits. QR codes were made to be robust in the face of errors, but over time this has been eaten into for aesthetic purposes. Businesses commonly put a logo in the center, eating up some error correction budget. This likely has a similar effect.

A few weeks ago I saw the first QR code I've personally witnessed that I'm pretty sure is completely unscannable. The company logo stretched well out of the center block. It was on the back of a semi in the Chicago area. I didn't get the greatest shot of it on my phone (as a passenger), because it was driving away as I tried, so it wasn't quite proof it couldn't scan, but I'm pretty sure it ate more than 100% of the error correction margin.

Based on the trends, I expect it is only the first of several I will see.

Re: Dithered QR Codes

#27

Post by arjie »

jerf wrote: post #24
gblargg wrote: post #17

This reminds me of car safety features, how drivers have become more complacent to offset the benefits. QR codes were made to be robust in the face of errors, but over time this has been eaten into for aesthetic purposes. Businesses commonly put a logo in the center, eating up some error correction budget. This likely has a similar effect.

A few weeks ago I saw the first QR code I've personally witnessed that I'm pretty sure is completely unscannable. The company logo stretched well out of the center block. It was on the back of a semi in the Chicago area. I didn't get the greatest shot of it on my phone (as a passenger), because it was driving away as I tried, so it wasn't quite proof it couldn't scan, but I'm pretty sure it ate more than 100% of the…

I’ve run into a few of these. And yesterday some kind of payment scanning QR code at SF’s Filipino Pistahan festival didn’t scan and I had to type in the text below. Annoying.

Re: Dithered QR Codes

#29

Post by theandrewbailey »

jerf wrote: post #24
gblargg wrote: post #17

This reminds me of car safety features, how drivers have become more complacent to offset the benefits. QR codes were made to be robust in the face of errors, but over time this has been eaten into for aesthetic purposes. Businesses commonly put a logo in the center, eating up some error correction budget. This likely has a similar effect.

A few weeks ago I saw the first QR code I've personally witnessed that I'm pretty sure is completely unscannable. The company logo stretched well out of the center block. It was on the back of a semi in the Chicago area. I didn't get the greatest shot of it on my phone (as a passenger), because it was driving away as I tried, so it wasn't quite proof it couldn't scan, but I'm pretty sure it ate more than 100% of the…

Doesn't everyone QA their QR codes? I thought it would be as obvious as making sure you got the right address and/or phone number on an ad before distributing it.

Re: Dithered QR Codes

#30

Post by dhosek »

I played around with this a bit, first I did a photo of a cat I just took at a cat cafe, but the black and white cat didn’t turn out well with the dithering algorithm, so then I tried a selfie and pushing the radius up, it came out looking good, but then I tried aiming my iPhone camera at the screen and it didn’t see a QR code, only the face from the selfie. The ones on the main page, though, worked fine.
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