Has anyone tried a long exposure to see if the motion smears into something discernible? Obviously harder to expose a bright screen without some ND since the shutter speed is the phone's main exposure control
If you zoom out to 25 % the text is clearly visible and screenshottable.
dasil003 · 39m ago
How do you take a “long exposure” screenshot? Isn’t every screenshot a perfect digital copy of a single frame or a full on video?
dylan604 · 37m ago
Clearly, I meant using a camera, and I'm guessing you knew that too
dice · 7m ago
Not the parent but that was not at all clear to me. I immediately thought of taking multiple successive instantaneous screenshots and then stacking them. I'm not sure I would have thought of using a camera within a few minutes to an hour, it's not a tool I would ever reach for normally.
Another idea I had with this concept is to make an LLM-proof captcha. Maybe humans can detect the characters in the 'motion' itself, which could be unique to us?
- The captcha would be generated like this on a headless browser, and recorded as a video, which is then served to the user.
- We can make the background also move in random directions, to prevent just detecting which pixels are changing and drawing an outline.
- I tried also having the text itself move (bounce like the DVD logo). Somehow makes it even more readable.
I definitely know nothing about how LLMs interpret video, or optics, so please let me know if this is dumb.
squigz · 1h ago
As if captchas aren't painful enough for visually impaired users...
bix6 · 2h ago
Ha cool! How’s it work?
Lalabadie · 2h ago
The only way to see the text is in the movement. The pattern across any single frame is entirely random noise.
altcognito · 2h ago
Fun side effect: staring at the letters for a bit makes the rest of the image move.
alliancedamages · 1h ago
You can also break it by recording the screen, of course.
kps · 1h ago
The text reappears when I screenshot it twice.
cryptoz · 2h ago
Had a lot of fun trying to break this. Turns out you can screenshot real easily by zooming out. Maybe there are other ways but I stopped trying :)
vunderba · 1h ago
yeah - I actually was initially confused since I wasn't having any issues screenshotting it but had forgotten that I have the default site zoom set to ~65%.
sans_souse · 2h ago
Not sure what you mean - I can screenshot it freely that's not the point the point is if you look then at the screenshot you cant discern the text because its a single frame now
This is on MacOS 15.6, Chromium (BrowserOS), captured with the OS' native screenshot utility. Since I was asked about the zoom factor, I now tried simply capturing it at 100% and it was still perfectly readable...
I guess the trick doesn't work on this browser.
dylan604 · 1h ago
I zoomed out to 90% and could make out something was there but wasn't easy to read. Zooming out further went back to just being noise. I also tried zooming in but with no success. What zoom level did you use and I guess we have to ask the standard what browser/version/OS/etc?? My FFv142 on macOS never took a screen grab like you did
dwg · 2h ago
Zooming out before taking screenshot and the text is no longer obfuscated. I tried and confirmed it works. In fact, the text is perhaps even more readable than the original.
anigbrowl · 1h ago
It depends how fast or slow your GPU is. I tried it and saw the effect you described, but within a second or two it started moving and was obscured again. Obviously you could automate the problem away.
dylan604 · 1h ago
Mine freezes the animation on zoom change. Not sure you could automate against that
UltraSane · 1h ago
Seems trivial to diff multiple screenshots to identify what parts move. Or just use a compression algorithm to do the same.
They even provide the source code for the effect:
https://github.com/brantagames/noise-shader
https://www.youtube.com/watch?v=Bg3RAI8uyVw
The effect is disrupted by introducing rendering artifacts, by watching the video in 144p or in this case by zooming out.
I'd love to know the name of this effect, so I can read more about the fMRI studies that make use of it.
What I've found so far:
Random Dot Kinematogram
Perceptual Organization from Motion (video of Flounder camouflage)
https://www.youtube.com/watch?v=2VO10eDIyiE
- The captcha would be generated like this on a headless browser, and recorded as a video, which is then served to the user.
- We can make the background also move in random directions, to prevent just detecting which pixels are changing and drawing an outline.
- I tried also having the text itself move (bounce like the DVD logo). Somehow makes it even more readable.
I definitely know nothing about how LLMs interpret video, or optics, so please let me know if this is dumb.
This is on MacOS 15.6, Chromium (BrowserOS), captured with the OS' native screenshot utility. Since I was asked about the zoom factor, I now tried simply capturing it at 100% and it was still perfectly readable...
I guess the trick doesn't work on this browser.