5 ms·

The funny thing is that no-one AFAICT has realized that the same content can be encoded in different-looking QR codes. Beside the obvious (different error-corre

by cafxx 3y ago

The funny thing is that no-one AFAICT has realized that the same content can be encoded in different-looking QR codes. Beside the obvious (different error-correction levels), the content itself can be changed while maintaining its semantic meaning (e.g. "https://example.com/foo https://example.com/foo", "HTTPS://EXAMPLE.COM/foo", or "HtTpS://eXaMpLe.CoM/foo" are all semantically identical) and even the QR encoding itself can be tweaked (e.g. by changing the version and mask, see the demo on https://www.nayuki.io/page/qr-code-generator-library https://www.nayuki.io/page/qr-code-generator-library). Each combination would yield a different-looking QR code that would encode the same meaning, and it could therefore allow the diffusion models even greater freedom. I'm sure somebody will get to this soon.

nayuki 3y ago
Other things you can tweak in a QR Code symbol without changing the decoded content: Error correction level, empty segments, segment encoding, deliberate addition of fully correctable errors, messing with padding bits/bytes after the terminator.
Kuinox 3y ago
There is a CRC so it's not as easy at it sounds.
- cafxx 3y ago
  None of what I wrote impacts the CRC calculation.
  - Kuinox 3y ago
    Diffusion models cannot generate a qr code by itself. The article even shows you need to generate the base image yourself. What you are proposing would mean bruteforcing the QR codes until we see a better shape.
    - Karliss 3y ago
      I wouldn't call generating a couple of semantically equivalent (but fully valid and 0 error) QR codes and giving each of them as inputs to diffusion model brute forcing. Even the normal AI image generation process often involves some trial and error. Generating a bunch of variants by changing random seed or slightly tweaking prompt keywords and choosing a result which looks the best. Doing multiple attempts with multiple different inputs doesn't seem more crazy than doing multiple attempts with same input and hoping for better results.
      - Kuinox 3y ago
        I often iterate my prompt on a fixed seed and by changing slightly the prompt to get the best results, so that wouldn't works well here.
      - eru 3y ago
        > I wouldn't call generating a couple of semantically equivalent (but fully valid and 0 error) QR codes and giving each of them as inputs to diffusion model brute forcing. If you have 20 letters in your URL, and you give the model each of 2^20 different ways to capitalise them, isn't that pretty close to brute-forcing?
    - sharperguy 3y ago
      It would be at least possible to write a python plugin for the 'automatic1111' ui which allows you to simply input the QR text, and have it generate images based on a variety of possible configurations in batch so you can go through and pick the one which is most aesthetically pleasing. edit: It would also be beneficial to have a script which automatically distorts the image in various ways and checks to see if it would be recognized by a QR code scanner, and give a score so you can see how likely it would be to be scannable in various conditions.
    - cafxx 3y ago
      Sure, but as I mentioned it has absolutely nothing to do with the CRC calculation, that is what you claimed.
cafxx 3y ago
Also not sure the diffusion model has been taught yet that it could in some cases choose to deliberately ignore a (small) fraction of some of the elements/blocks, if it helps with composition. Or even better just wire up a QR decoder to the loop and automatically reject images that don't decode correctly, and let the model sort out how far it can go.
- eru 3y ago
  You'd need to inject a lot of noise (and different kinds of noise, and different implementations of QR decoders) before you present the image to the QR decode, to make sure you are still producing a robust QR code.
tln 3y ago
QR codes have several different bit-pattern masks, which an encoder should choose between to avoid blocks or runs.. so even without altering the URL there are different outputs. [A-Z0-9] encodes a lot more efficiently than [a-zA-Z0-9] so there are other considerations when altering a url.
- cafxx 3y ago
  Yes, that's what I meant.
matsemann 3y ago
I think this has been done for a long time? I made this one that looks like a VLC logo and links to VLC, back in 2013. https://imgur.com/a/rq8WzGm https://imgur.com/a/rq8WzGm inspired by some post I read at the time. If you scan it, you realize it's putting lots of "junk" at the end of the URL that doesn't change its meaning, but is used to tweak how the QR code looks. The URL is on the form videolan.org/#234234234523453455...
- cafxx 3y ago
  Sorry, yes, I should have clarified I meant "no-one has done it in the current batch of diffusion-based experiments". As you point out it has been done multiple times before, e.g. https://research.swtch.com/qart https://research.swtch.com/qart (online demo https://research.swtch.com/qr/draw/ https://research.swtch.com/qr/draw/).

by cafxx 3y ago

nayuki 3y ago

Other things you can tweak in a QR Code symbol without changing the decoded content: Error correction level, empty segments, segment encoding, deliberate addition of fully correctable errors, messing with padding bits/bytes after the terminator.

Kuinox 3y ago

There is a CRC so it's not as easy at it sounds.

cafxx 3y ago
None of what I wrote impacts the CRC calculation.
- Kuinox 3y ago
  Diffusion models cannot generate a qr code by itself. The article even shows you need to generate the base image yourself. What you are proposing would mean bruteforcing the QR codes until we see a better shape.
  - Karliss 3y ago
    I wouldn't call generating a couple of semantically equivalent (but fully valid and 0 error) QR codes and giving each of them as inputs to diffusion model brute forcing. Even the normal AI image generation process often involves some trial and error. Generating a bunch of variants by changing random seed or slightly tweaking prompt keywords and choosing a result which looks the best. Doing multiple attempts with multiple different inputs doesn't seem more crazy than doing multiple attempts with same input and hoping for better results.
    - Kuinox 3y ago
      I often iterate my prompt on a fixed seed and by changing slightly the prompt to get the best results, so that wouldn't works well here.
    - eru 3y ago
      > I wouldn't call generating a couple of semantically equivalent (but fully valid and 0 error) QR codes and giving each of them as inputs to diffusion model brute forcing. If you have 20 letters in your URL, and you give the model each of 2^20 different ways to capitalise them, isn't that pretty close to brute-forcing?
  - sharperguy 3y ago
    It would be at least possible to write a python plugin for the 'automatic1111' ui which allows you to simply input the QR text, and have it generate images based on a variety of possible configurations in batch so you can go through and pick the one which is most aesthetically pleasing. edit: It would also be beneficial to have a script which automatically distorts the image in various ways and checks to see if it would be recognized by a QR code scanner, and give a score so you can see how likely it would be to be scannable in various conditions.
  - cafxx 3y ago
    Sure, but as I mentioned it has absolutely nothing to do with the CRC calculation, that is what you claimed.

cafxx 3y ago

Also not sure the diffusion model has been taught yet that it could in some cases choose to deliberately ignore a (small) fraction of some of the elements/blocks, if it helps with composition. Or even better just wire up a QR decoder to the loop and automatically reject images that don't decode correctly, and let the model sort out how far it can go.

eru 3y ago
You'd need to inject a lot of noise (and different kinds of noise, and different implementations of QR decoders) before you present the image to the QR decode, to make sure you are still producing a robust QR code.

tln 3y ago

QR codes have several different bit-pattern masks, which an encoder should choose between to avoid blocks or runs.. so even without altering the URL there are different outputs. [A-Z0-9] encodes a lot more efficiently than [a-zA-Z0-9] so there are other considerations when altering a url.

cafxx 3y ago
Yes, that's what I meant.

matsemann 3y ago

I think this has been done for a long time? I made this one that looks like a VLC logo and links to VLC, back in 2013. https://imgur.com/a/rq8WzGm https://imgur.com/a/rq8WzGm inspired by some post I read at the time. If you scan it, you realize it's putting lots of "junk" at the end of the URL that doesn't change its meaning, but is used to tweak how the QR code looks. The URL is on the form videolan.org/#234234234523453455...

cafxx 3y ago
Sorry, yes, I should have clarified I meant "no-one has done it in the current batch of diffusion-based experiments". As you point out it has been done multiple times before, e.g. https://research.swtch.com/qart https://research.swtch.com/qart (online demo https://research.swtch.com/qr/draw/ https://research.swtch.com/qr/draw/).