Ghost Font: A font that humans can read but AI cannot • Hacker News Board

Re: Ghost Font: A font that humans can read but AI cannot

#101

Post by grahamburger » Sat, Jul 11, 2026, 4:45 PM UTC

dragontamer wrote: post #86

The hallucination of messages bothers me severely. Especially with AI being deployed to ancient, difficult problems like the Herculaneum scroll. EDIT: To be clear, I'm talking about the "Written in Morse Code" example, fully hallucinated text. The AI agents seeing a decoy message isn't as bothersome to me.

It's not fully hallucinated, I don't think. If you squint, you really can see what I assume is the 'decoy message', I'm fairly sure it says 'WRITTEN IN GHOST FONT'. It seems more likely to me that the LLM found 'Written In', noticed similar 'optical illusion' type memes, and hallucinated/assumed the 'morse code' bit.

Re: Ghost Font: A font that humans can read but AI cannot

#102

Post by [deleted] » Sat, Jul 11, 2026, 4:50 PM UTC

rav wrote: post #82

> For example, it would be interesting to incorporate Ghost Font into CAPTCHA systems, as most systems are easily solved by AI today. It seems to me like it should be easy enough to take Ghost Font, apply normal video compression techniques, and analyze the compressed signal to recover the visual outline of the letters, which you would then analyze with OCR (or an AI I guess ...). In other words, a novel CAPTCHA tech…

[deleted]

Re: Ghost Font: A font that humans can read but AI cannot

#103

Post by starcast2026 » Sat, Jul 11, 2026, 4:50 PM UTC

singularity2001 wrote: post #58

stabbles wrote: post #40

Earlier quoted context omitted.

If you take a frame you see it's neither random nor dots: https://i.imgur.com/CgtyGjl.png From a single frame you can definitely identify boundaries because the dots are sliding and get truncated.

Exactly. It's a good idea, badly executed.

Just to add some drama - this feels like a perfect competition between humans & bots!

Re: Ghost Font: A font that humans can read but AI cannot

#104

Post by freehorse » Sat, Jul 11, 2026, 4:59 PM UTC

It is smart, but it is not impossible to crack algorithmically imo. In particular, one can take two consecutive frames and run perturbations moving one frame around (ie shift the indexes) to find where the difference between the two consecutive frames minimises. Then subtract these two (perturbed) frames and ocr it. Works easily if the movement is linear/one-directional.

I did this in 20 lines of code (checking only vertical perturbations), and this is what I get with subtracting frame 7 from frame 1:

https://imgur.com/a/only-human-can-read-this-vfDe6ZA

Re: Ghost Font: A font that humans can read but AI cannot

#105

Post by TaupeRanger » Sat, Jul 11, 2026, 5:00 PM UTC

IvanK_net wrote: post #90

Instead of "AI cannot" you should always say "current AI cannot".

Even that would be false.

Re: Ghost Font: A font that humans can read but AI cannot

#106

Post by lutusp » Sat, Jul 11, 2026, 5:04 PM UTC

> ... immediately readable to a human eye, but even leading AI models can't decipher it easily.

For the moment. This pattern is easy to code -- it relies on the premise that a character has an inside and an outside. Outside, a pattern ascends. Inside, the reverse. Based on that simple encoding idea, decoding will be equally simple.

Re: Ghost Font: A font that humans can read but AI cannot

#107

Post by pessimizer » Sat, Jul 11, 2026, 5:08 PM UTC

I don't think this works - I suspect it's the decoy that's doing the work. Once the decoy is seen, the LLM stops looking. It also seems pretty much effective on a lot of people, too.

Now that "Ghost Font" will be in the training material, LLMs will go "this looks to be written in Ghost Font, and as such has two messages."

Re: Ghost Font: A font that humans can read but AI cannot

#108

Post by wavemode » Sat, Jul 11, 2026, 5:08 PM UTC

Kiro wrote: post #99

GPT-5.6 had no problem seeing the text when giving it a video recording of it. "No problem" as in using temporal analysis with optical flow and vertical-displacement maps to estimate how the image moved, and combine those into a motion map with increased contrast to see the text. I didn't give it any instructions though, just asked it what it said.

Do you have a link to this chat?

Re: Ghost Font: A font that humans can read but AI cannot

#109

Post by junto » Sat, Jul 11, 2026, 5:13 PM UTC

I can’t read magic eye pictures and I can’t read this either. Maybe astigmatism makes it unreadable to me?

It just looks like static on old tvs to me.

Re: Ghost Font: A font that humans can read but AI cannot

#110

Post by beagle3 » Sat, Jul 11, 2026, 5:16 PM UTC

ihsoj wrote: post #98

rav wrote: post #82

> For example, it would be interesting to incorporate Ghost Font into CAPTCHA systems, as most systems are easily solved by AI today. It seems to me like it should be easy enough to take Ghost Font, apply normal video compression techniques, and analyze the compressed signal to recover the visual outline of the letters, which you would then analyze with OCR (or an AI I guess ...). In other words, a novel CAPTCHA tech…

Yes, it may be useful to replace current CAPTCHA, but this does not provide the positive side-effects of CAPTCHA where user-submitted data is used to train the unknown images or reinforce the labelling of existing image segments.

It’s been years since captcha was contributing to labeling.