It's easier than ever to de-censor videos

Yeah, that is pretty wild.

I recall a co-worker doing something related(?) for a kind of fun tech demo some ten years or so ago. If I recall it was shooting video while passing a slightly ajar office door. His code reconstructed the full image of the office from the "traveling slit".

I think about that all the time when I find myself in a public bathroom stall.... :-/

Line scan cameras operate on this principle, and are still used in various ways to this days. I'm especially partial to the surreal photos generated by them at the end of cycling races

https://finishlynx.com/photo-finish-trentin-sagan-tour-de-fr...

> I think about that all the time when I find myself in a public bathroom stall.... :-/

Walk past a closed bathroom stall fast enough and you can essentially do that with your own eyes. Or stand there and quickly shift your head side to side. Just don't do it on one that's occupied, that's not cool.

"Sir, why do you keep running back and forth in the bathroom?"

I was not aware of those.

Reminds me of slit-scan as well. And of course rolling shutters.

> His code reconstructed the full image of the office from the "traveling slit".

This method is commonly used in vision systems employing line scan cameras. They are useful in situations where the objects are moving, e.g. along conveyors.

Even today most cameras have some amount of rolling shutter—the readout on a high-megapixel sensor is too slow/can't hold the entire sensor in memory instantaneously, so you get a vertical shift to the lines as they're read from top to bottom.

Global shutter sensors of similar resolution are usually a bit more expensive.

With my old film cameras, at higher shutter speeds, instead of opening the entire frame, it would pass a slit of the front/rear shutter curtain over the film to just expose in a thousandth of a second or less time.

This reminds me of https://github.com/jo-m/trainbot, a neat example of stitching together frames of passing trains to form a panorama.

This frontend presents them nicely: https://trains.jo-m.ch

The dither effect. Same as seeing through splayed fingers on a franticly oscillating hand.

Sorry if you're already aware, but in case not: The weird huge gap around the edge of cubical doors in pubic toilets is specific to the US. (For those that don't know, it's literally 1 or 2 cm.) In Europe you just get a toilet door that shuts properly and there's no slit to reconstruct.

I remember my first visit to a toilet in the plush US office of a finance company and thinking WTF are they doing with their toilet cubicle? I only found out later that it's common there.

This is the nerdiest way I've ever seen someone talk about John Cena

Surprised I've never come across this idea before

It can be much more than 2cm. The US really hates people for some reason.

What's funny is that the described action didn't click until your comment.

Similar to

https://hackaday.com/2024/08/17/olympic-sprint-decided-by-40...

I love line scan cameras. Wikipedia has an awesome photo of a tram taken with a line scan camera on the relevant wiki page[1].

I've just moved to a house with a train line track out front. I want to see if I can use a normal camera to emulate a line scan camera. I have tried with a few random YouTube videos I found [2].

I think the biggest issue I face is that there simply isn't the frame rate in most camera's to get a nicely detailed line scan effect.

---

[1]: https://en.wikipedia.org/wiki/Line-scan_camera

[2]: https://writing.leafs.quest/programming-fun/line-scanner

> Walk past a closed bathroom stall fast enough and you can essentially do that with your own eyes

Only in the US. The rest of the world has doors without a gap at the sides.

For a long time I've wanted to install one of these to pull graffiti off of trains. As art goes, graffiti is one of the last 'free' expressions where it is essentially truly anonymous and definitely not for money. Being free of those constraints, I think, frees the mind to truly create.

And I'd love an archive somewhere of some of the truly awesome train art I've seen.

Doors in Vietnam are exactly the same as in the US.

You clearly haven't traveled much so you should refrain from sweeping generalisations.

Well duh it won’t work if there’s no gap, no matter what country you’re in. It doesn’t get around the laws of physics.

Not every bathroom stall in the US has gaps either.

I don't quite know how to respond to that.

I am aware, and of course this works for any gap you might be walking past. Plenty of newer bathroom stalls here do not have a gap.

I'm sorry, but what point are you trying to make? Aside from: "Yeah, duh, you can't see through a fucking wall".

Mine was that, typically, people from outside the US, only ever experience toilet stalls with gaps when they visit the US.

Not every stall has gaps there, but I don't recall ever encountering it here in the EU.

I believe it started as an anti-drug thing more than 50 years ago but somehow it became pervasive even in fairly high end settings where you would never expect such measures. Cargo cult bathroom construction IMO.

Luckily things seem to be gradually changing.

here you go... https://trains.jo-m.ch/#/trains/44010

A normal frame rate is probably enough if you do it with groups of columns rather than a single column of pixels. That's what https://trains.jo-m.ch/ does with a Raspberry Pi camera, posted in https://news.ycombinator.com/item?id=35738987 with lots of questions and answers.

And if you "reverse" this idea you can make a "holographic(?) display"[0].

[0] - https://www.youtube.com/watch?v=ric-95ig5oE