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Comment by citilife | Hacker News Reader

The problem with this is that it's prone to error (doesn't have error correcting bits). Unfortunately, that combined with speed of scanning is really what's key for codes.

I have worked in the space, making some strides in speed & error correction.

Some of my public work is here: https://austingwalters.com/chromatags/

Your best bet is actually an overlay of two codes. A regular image (for humans), plus a code embedded in a color space (see linked post for how to do that).

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> The problem with this is that it's prone to error (doesn't have error correcting bits

Doesn't the use of the latin alphabet act a bit like an error correction code here? In contrast to a pure binary code you know that only certain shapes are valid, which should allow you to do some guessing if you don't get a perfect match.

Doesn’t help if a whole cell is missing, whereas with QR codes chunks can be entirely gone without consequence.

Can you give some practical examples of where that would be useful? Honestly curious, don't know much about this space.

A lot of applications centralize their logo in a QR code, obscuring a significant chunk. Yet the code scans fine and there is some nice custom recognizability for which service it is.

Maybe scanning from photos where the code is obscured, bad quality, almost-trashed physical codes.

Physical sticker exposed to the environment. Scrapes/marks are common, they would render the “HR” code useless, but the QR would be fine. Or at least stay fine for longer. So the trade off becomes: do I post something that will be accessible to everyone, even those without a phone, for a week; or do I post something that will be accessible to everyone with a phone for two weeks. Given almost everyone has a phone, the answer is obvious. (Making up the times, but you get the idea)

"Guessing" and "a bit like" are key qualifiers here; error correction codes in QR provide a pretty hard guarantee and won't scan corrupted. With this scheme, who knows?

The whole point of having human readable code is to help avoid being scammed, so having a code embedded that a human cant read but is what actually used for the link defeats the purpose

Also, most likely all URLs would end up coded like https://go.to/abcdef

Edit: just found clicking go.to redirects to flock.com.

So what happens when someone makes an image that appears like one url but scans as a different url? goDgle.com?

Then that is a failure of the protocol

What if the data is human readable but the error correction is only machine readable?

There still might be room for scams if the error correction is too clever, maybe it could only be a checksum?

Thank you for sharing your chroma tags work.

Could the same technique be applied to QR codes? Would it improve QR read times?

At rush hour I have to wait for many people to scan their QR code train tickets, it is surprisingly slow.

Yes, the technique is general. Take a QR code and do the same manipulations and you get 2x scanning speed and 4x redundancy with no change in the algorithm.

I've actually improved it significantly since then, where it's possible to also store 2^8 data in something resembling a QR code, while keeping the same scanning speed as today.

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