Ward Cunningham and I did something similar back in 2008.
We were both at a startup in Portland and our office was along the railroad tracks east of the Willamette. We were up on the 4th or 5th floor right above a lot of train traffic including Amtrak.
I brought in some extra Mac gear I had including one of the early iSight cameras which back then was an external device you stuck on the top of your display and connected to the Mac via FireWire. We set it up and rolled the desk over to the window in the office and turned the camera around pointing down at the tracks and Ward got to work hacking something up to do a slit scan.
It was a fun little project; the speed of the trains affected the horizontal compression of the images. We could tweak the software to expand or contract the size of the image by adjusting the number of slit scans per unit of time. Of course, that affected the exposure but I recall the camera having some automatic adjustments that gave us trouble.
That's about all we did with it. Just a quick afternoon hacking project. Neither of us thought much about it at the time so we didn't save anything.
I've posted this here before but I have been creating animations using a similar process with a regular camera and manually splicing the frames together. [1,2,3] The effect is quite interesting in how it forces focus on the subject reducing the background into an abstract pattern. Each 'line' is around 15px wide. I think I went through exactly the same thought process as the author, funny how ideas can come up independently like this.
I also shot a timelapse of the Tokyo skyline at sunset and applied a similar process [4], then motion tracked it so that time is traveling across the frame from left to right[5]. Each line here is 4 pixels wide and the original animation is in 8k.
I gotta wonder. Owen from RanOutOnARail could make some incredible wide pictures from his journeys if he had this setup. Been watching his YouTube channel for years [0], [1]. He has a Patreon account with more videos [2].
He use to have a lot more videos on YouTube. It's illegal to ride trains the way he does, but his videos helped get me through the long time of the covid pandemic after I would stop work for the day.
I love this sort of project and write-up. Inspiring to try something a bit different and dance on that line between practicality and artwork. The in-progress "scans" are themselves an interesting stretching of time and space, even if they aren't what the artist is ultimately going for.
Same here. I'm especially a big fan of the "using x as y" format (using youtube as a mountable file system, using my wii to host a web server, etc). I feel like they're a lot less common on here these days than a year or 2 ago
Also, I think at some point someone shared some Japanese website where someone did these high quality photos of Japanese trains with a similar technique?
Great writeup! Planned doing the same thing Herr in germany. Thought a Smartphone camera would be enough but there no way to access the camera2 api for those highspeed recordings. I took 1h long 240hz 4k vertikal videos (out of the Schwebebahn in Wuppertal) which could be displayed by MacOS preview. Right no im waiting for a good gaussian splatting tool to create the driving of the "Train” in Blender. The newest Lingbot-map is unfurtunatly not really trained for sideway movement. I always asked myself if the sideway movement and the Parallaxe would make way easier to infer the distance and the 3d scanning capabilities because the pixel only really move one as long you dont drive turns
Ohhh, nice; happy to have a chat on the subject; suggest a messaging option to discuss further if you're interested. Check out keybase on my profile for some listed contact options; you can also use the padlock symbol in the menubar there to PGP encrypt a message to me and share that through any suitable channel that can handle that ascii.
Edit: I've captured and extracted-to-textured-mesh Mirker Bahnhof before it got covered by the scaffolding; if you're going to do another recording I'd highly recommend you include an IMU recording and ideally (though much less critically) a GNSS raw measurements recording that includes carrier phase. I've got a recorder for the latter that exposes a simple USB-serial port that should work great unless the GTW15 windows are EMI-shielding (but iirc they aren't).
This project is more deeply technical but one thing I find fun is to take a video from a moving train and create a video stereogram by having one eye lagging in time/distance behind the other eye, letting you create very long baseline stereograms.
It's fun to be able to see the 3d effects on passing bridges, etc., and for large baselines on long straight stretches you can see the 3d structure of clouds in a fascinating way.
This is so cool. It's a much better version of what Bill Cheswick and I did almost 15 years ago with footage from a SFO->EWR flight: https://cscheid.net/static/windowseat/
Not quite in the same spirit but I suppose one could talk of railway operators using the railway network as a flatbed scanner when they send maintenance vehicles out to scan the railbed for defects.
It was one of the first large-scale commercial applications of barcodes, and at one point 95% of railroad cars were equipped with it. Could've been a success, but it was a few decades too soo, and a handful of small but crucial implementation flaws doomed it to abandonment only a decade later.
Nice. It reminds me of a blog of a guy who had mounted a flatbed scanner on an electrical motor to make a digital photo before digital camera existed. He had added one of the resulting picture of his backyard. It was one of the most viral Slashdot post at the time.
Oh, Matthias Wandel, of course. This would have been back when he was writing software for Blackberry instead of his current semi-retired woodworking YouTubing
Line scan cameras are (were?) also very common in industrial applications. It is the best way to take images of objects on a rapidly-moving conveyor belt as you don't have to be worried about blurring due to long shutter times, and you can achieve incredible frame rates.
The downside is that they are highly specialized (in other words: expensive) and require knowledge of the belt speed to reconstruct a proper image. I would not be too surprised if modern high-framerate video cameras took over a decent chunk of that niche.
Railway operators do this to inspect tracks: Mount a line-scan camera that looks down, get an "infinite" image of the tracks, inspect for anything interesting.
... as in not very good compared to normal camera ? Acceleratometer-based correction can only do so much
Normal camera allows you to get a snapshot of 2D area instead of 1D area so you can make any correction for movement afterwards. With linear one you just get artifacts like the introductionary pic being very wobbly up and down.
We were both at a startup in Portland and our office was along the railroad tracks east of the Willamette. We were up on the 4th or 5th floor right above a lot of train traffic including Amtrak.
I brought in some extra Mac gear I had including one of the early iSight cameras which back then was an external device you stuck on the top of your display and connected to the Mac via FireWire. We set it up and rolled the desk over to the window in the office and turned the camera around pointing down at the tracks and Ward got to work hacking something up to do a slit scan.
It was a fun little project; the speed of the trains affected the horizontal compression of the images. We could tweak the software to expand or contract the size of the image by adjusting the number of slit scans per unit of time. Of course, that affected the exposure but I recall the camera having some automatic adjustments that gave us trouble.
That's about all we did with it. Just a quick afternoon hacking project. Neither of us thought much about it at the time so we didn't save anything.
[1] https://youtube.com/shorts/VQuI1wW8hAw [2] https://youtube.com/shorts/vE6kLolf57w [3] https://youtube.com/shorts/QxvFyasQYAY
I also shot a timelapse of the Tokyo skyline at sunset and applied a similar process [4], then motion tracked it so that time is traveling across the frame from left to right[5]. Each line here is 4 pixels wide and the original animation is in 8k.
[4] https://youtu.be/wTma28gwSk0 [5] https://youtu.be/v5HLX5wFEGk
I gotta wonder. Owen from RanOutOnARail could make some incredible wide pictures from his journeys if he had this setup. Been watching his YouTube channel for years [0], [1]. He has a Patreon account with more videos [2].
He use to have a lot more videos on YouTube. It's illegal to ride trains the way he does, but his videos helped get me through the long time of the covid pandemic after I would stop work for the day.
[0] https://youtube.com/@ranoutonarail?si=ElAeMpcrJASsE3Ov
[1] https://youtube.com/@rooar2?si=bx1AG5kp2r4rfzcq
[2] https://www.patreon.com/u40099464
edit: I made this site to only show non-ai related posts like this one https://www.unslop.news/
https://slitscan.space
Press and hold your phone screen to switch between the front/back cameras, or hit "c" on a computer. Tapping the screen saves the image, as does "s".
https://i.dllu.net/2017-11-23-14-30-54_stack_cdb771693eea9fe...
Also, I think at some point someone shared some Japanese website where someone did these high quality photos of Japanese trains with a similar technique?
It was impossible (for me at least) to get a scan without shifting my hand position on the X-axis while also sliding the scanner down the picture.
Also, I seem to recall the scanner I used was only capable of outputting 1-bit dithered black and white pictures. This was late 80s/early 90s tech.
https://news.ycombinator.com/item?id=49127920
Edit: I've captured and extracted-to-textured-mesh Mirker Bahnhof before it got covered by the scaffolding; if you're going to do another recording I'd highly recommend you include an IMU recording and ideally (though much less critically) a GNSS raw measurements recording that includes carrier phase. I've got a recorder for the latter that exposes a simple USB-serial port that should work great unless the GTW15 windows are EMI-shielding (but iirc they aren't).
It's fun to be able to see the 3d effects on passing bridges, etc., and for large baselines on long straight stretches you can see the 3d structure of clouds in a fascinating way.
For example: https://railgallery.wongm.com/ev120-inspection-vehicle/F144_... https://www.youtube.com/watch?v=5TKDw2E_PBQ
It was one of the first large-scale commercial applications of barcodes, and at one point 95% of railroad cars were equipped with it. Could've been a success, but it was a few decades too soo, and a handful of small but crucial implementation flaws doomed it to abandonment only a decade later.
https://www.finishlynx.com/
The downside is that they are highly specialized (in other words: expensive) and require knowledge of the belt speed to reconstruct a proper image. I would not be too surprised if modern high-framerate video cameras took over a decent chunk of that niche.
... as in not very good compared to normal camera ? Acceleratometer-based correction can only do so much
Normal camera allows you to get a snapshot of 2D area instead of 1D area so you can make any correction for movement afterwards. With linear one you just get artifacts like the introductionary pic being very wobbly up and down.