- Line scan camera image processing: https://daniel.lawrence.lu/blog/2025-09-21-line-scan-camera-... Previous discussions:
- https://news.ycombinator.com/item?id=44996938
- https://news.ycombinator.com/item?id=46383593
- https://news.ycombinator.com/item?id=46388084
- Line scan camera image processing 2: https://daniel.lawrence.lu/blog/2026-08-02-line-scan-camera-...
Are there other photo types you've thought about taking? (I don't know very much about the topic. Rocket launches? Cruise ships? 360/Cylindrical line scan sweeps?)
I assume the train rails and constant motion are part of the appeal of making trains the subject. I can't exactly think of parallels, maybe a factory assembly line.
https://i.dllu.net/swing_07_7668f7f16ff7ac2a.png
Also motorcycle cops:
https://commons.wikimedia.org/wiki/File:San_Francisco_Police...
I never thought about it until seeing these, but line scans yield an orthographic projection in the scan direction. There was a little bit of uncanny valley being able to see parts of the front/back of the car that would have normally been compressed out occluded by perspective.
...and I'll be surprised if I don't see these pictures hanging in a bank/startup lobby at some point!
Adam Magyar and Jay Mark Johnson have line scan photos in fine arts as well, and they were in fact a big source of inspiration when I started out on my own line scan journey in 2017.
- https://www.magyaradam.com/wp/?page_id=368
- https://www.jaymarkjohnson.com/works
Seth Itow, Philomena, and Elm-chan both also have hobbyist line scan camera setups:
- https://www.sethitow.com/posts/2026-linescan/
- https://elm-chan.org/works/lcam/report.html (be sure to scroll down and click on the train pics)
There are also Japanese rail fans:
- https://kr64.seesaa.net/ with a bewilderingly huge collection of trains all over Japan,
And faux-line scan cameras using regular video cameras, stitching together thin chunks rather than 1 px columns:
- https://x.com/yamakox/status/2089934720759144653
- https://kakeyama.image.coocan.jp/index.htm
- https://trains.jo-m.ch/#/trains/list
Line scan cameras are also commonly used for machine vision in the rail industry to inspect trains for damage and detect graffiti and stuff. And conversely, line scan cameras mounted on trains are used to inspect rails and tunnels.
Your work is extremely beautiful, and I am truly envious of your work, the aesthetic is awesome. I want to do it on the cheap though, with a regular phone as camera.
I think you have given me the directions needed to make some bold steps towards getting what I want out of the 'medium'.
https://github.com/vitroid/TrainScanner
It converts a regular video into a line scan style photo. It works by stitching together small chunks rather than 1px thin slices, so the background has a repetitive texture rather than being smooth horizontal stripes. But at lower resolutions, it looks similar, especially if you pick a spot with a clean background. Also the trains turn out very detailed.
Example work by Kakeyama from Japan using this: https://kakeyama.fan.coocan.jp/tec/e5e8r.htm
(previously on HN frontpage, and before that, at EMF Camp!)
By the way, I recognize your username as the person that Philo credits with "rewriting grindstone in idiomatic NumPy". That's super cool!
[1] https://github.com/FlamingSpork/grindstone/issues/1
[2] https://daniel.lawrence.lu/blog/2026-06-12-standalone-cnc-li...
I suppose the subjects moved past the camera perpendicular to the lens direction, so you only see one side.
Are there any examples of what it looks like with a line scan camera when a subject goes past at an angle?
Also, for anyone setting up a tripod with a tripping hazard in public, do consider public liability insurance :)
I wish they could do something about fare evasion. I ride Muni fairly often (both buses and trains), and I see maybe 20% of people paying when they get on. I know some of the remaining 80% probably have monthly passes or something and don't strictly need to tag on, but I can't imagine it's a large percentage. Biggest offenders seem to be out-of-towners who are going to Chase Center or Oracle Park events (I live in the Dogpatch and see a lot of that on event days). There's no excuse now that the fare terminals accept NFC credit cards too (and not just Clipper cards). I expect getting more people to pay could solve some of these funding problems, or at least make them less severe.
(I do wonder if the cost of fare enforcement exceeds what they'd recover in fares, though...)
Looking at the list of options on [2], your observed 1-in-5 Clipper taps seems within the realm of plausibility; there are a lot of ways to pay for Muni that aren’t visible to fellow passengers. In particular, out-of-towners who plan to ride Muni a lot are likely to get a MuniMobile (or, for the old-fashioned, paper) pass; and a ticket to any Chase Center event also counts as a Muni day pass. You also mentioned monthly passes (I know a lot of people who get them from their company’s commuter benefits), and there’s also transfers: not only are “single ride” fares valid for 2 hours, but if you board after 8:30pm you can’t tap again, because Clipper can’t handle it and you’ll be double charged!
[1] https://www.sfmta.com/projects/paying-your-fares-keeps-us-mo... [2] https://www.sfmta.com/getting-around/muni/fares
Reminder that vast majority of the fare is covered by taxes (Roughly 87%). I wish they just funded the remaining 13% instead.
It might not even cost that much more considering all of the expenses involved with hiring more staff (Salary/healthcare/pensions etc.) to collect the last 13 cents on the dollar.
Muni can be 100% free without increasing taxes too. The people using public land to store their private vehicles are not paying their fair share. Proper parking pricing and enforcement could easily pay for Muni’s deficit.
But came here to say the same thing. There is an advertising campaign in SF right now to encourage people to vote to give Muni more money (again) in November, because they can't cover their essential costs. This...looks pretty non-essential to their core mission to me.
They should have done everything they can inside their org to cut costs, before going to ask residents to give them more money.
Now I hope - maybe this is primarily funded by donations / grants or volunteer work, and SFMTA contributes very little to this. If so great - but it would have been wise for them be very clear about that.
I obviously am I biased, and think this is very very cool. There are many intangibles here beyond the budget numbers; a bit of history, a bit of whimsy, a bit of color to what is often utilitarian (public transit). It certainly attracts tourists to the city (I was pretty surprised at the number of out of towners at Muni heritage weekend).
But I do think it's important, not just for tourism but also as a legitimate connector along the Embarcadero corridor that otherwise has no public transit along it. Agree that a breakout of the cost of maintaining these things would be appreciated, not sure if that exists in clear terms, but I don't think it's massive. For example Car 162 was damaged in a collision in 2014, and took 12 years to fix and return to service. For many gripmen / Muni restorationists working for the city, it's a side project.
And while I'm here, I'd be remiss if I didn't post an article about Maurice Klebolt, one of the biggest advocates for vintage transit in San Francisco. It describes how he acquired car 106 from the Soviet Union [2]
[1]: https://www.streetcar.org/streetcars/162-162-muni-1950s-live...
Would you be up for posting it in, say, a couple months and then email hn@ycombinator.com? We'll put it in the SCP [2] for sure, so it will get a random placement on HN's front page.
[1] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
At 2024 numbers in this SPUR report:
Cable car 872 streetcare 631 lightrail 412 system avg 327 motorbus 302 trolleybus 281
So canceling each cable car could IIUC, allow the system to add roughly 3 electric buses.
https://www.spur.org/sites/default/files/2026-03/SPUR_Taking...
> Cable cars are a symbol of San Francisco, a major tourist attraction, and an indelible feature of the city’s cultural and historical landscape. [...] While SPUR doesn’t recommend changing SFMTA’s role in cable car operations, the agency may wish to explore options to generate additional revenue from the cable car system or seek supplemental support from the city’s budget, given the outsized expense of providing cable car service and the unique value this mode brings to the city as a cultural attraction. SFMTA already acknowledges the special status of cable cars by pricing them differently from other modes and by excluding cable car service from some of its passes and fare discount programs.
Apart from that, I suspect the per-service-hour figure is particularly misleading for cable cars and removing one cable car from the schedule would free up significantly less than $871: there is a significant fixed overhead (from power usage and cable wear) to having the system running at all, regardless of how many cars are on it.
1: https://codelibrary.amlegal.com/codes/san_francisco/latest/s... 2: https://www.cablecarmuseum.org/60th_Anniversay.html
Each cable car trip costs Muni about US$20. They charge about $8.
I was amazed when I first found out how the grip worked. I figured they clamped pulleys around the cables and then applied brakes to the pulley system. Nah. It's brutally simple. They squeeze two soft metal plates around the cable. The cable wears a groove in the plates during starting and stopping. Those plates are replaced every 3-4 days. The cables are replaced every few months.
Plus the thousand or so pulleys under the street need regular attention. The whole system has way too many friction points, which means intensive maintenance.
The PCC streetcars were a really good design, built for efficient operation with modest maintenance. Their successor in San Francisco was built by Boeing Vertol, which totally botched it.[1] None of those cars are still around. The PCC cars roll on.
[1] https://en.wikipedia.org/wiki/US_Standard_Light_Rail_Vehicle
- People who want to go up market can transfer to the KLM at Embarcadero and if they're going to Castro (or maybe Church?) they may also get there faster.
- If tourists want to see an old-timey street car, they could ride one perhaps half the distance, only along the water with views Coit tower, and the eastern end of the line would be right by the Railway Museum anyway. And we could run perhaps half as many cars.
You could pull the J up from underground too using the same low-floor LRV model chosen for the new F, having it turn at Church & Market rather than making an awkward diversion to Church & Duboce first.
What lens are you using? Does it have to cover 135 format?
Previously I've also used these full frame lenses:
- Myutron 50mm f/2.6 (Shinkansen N700A, SF Cable Car 2017)
- Voigtlander Nokton 58mm f/1.4 (Brisbane Queensland EMU)
- Samyang 135mm f/2 (Madrid AVE Class 102 and Shanghai maglev)
- Voigtlander Apo Lanthar 125mm f2.5 (Yamanote Line, CR400AF)
- Voigtlander Apo Skopar 90mm f/2.8 (London Tube photos)
- Voigtlander Ultron 35mm f/1.7 (Hong Kong trams)
and APS-C lenses:
- Cheecar 50mm f/1.2 (Osaka trains)
- Samyang 85mm f/1.8 CS (Caltrain)
