Using the railway network as a flatbed scanner
Points and comments are a snapshot, not live.
A hobbyist builds a line-scan camera to capture panoramic photos from trains and ferries.
The author used an industrial Basler ruL2048-19gm linear camera (1x2048 pixels, ~19,000 lines/sec) bought on eBay for ~$70, a 28mm lens, and a SAMD21 microcontroller with accelerometer/GPS to measure speed and correct image distortion. The camera captures a single vertical line repeatedly as the train moves; software stitches lines into wide images up to 56,894x2,048 pixels. Challenges included accelerometer noise, GPS signal loss in tunnels, serial port buffer issues, and needing bright daylight due to minimum 1/100s exposure. Results include legible station signs and a sharp image of Boston's Longfellow Bridge.
What commenters are saying
Commenters shared related projects: a 1990s scanner-on-a-motor by Matthias Wandel, Ward Cunningham's 2008 slit-scan from a Portland office window, and a JavaScript slit-scan toy. Railway operators use line-scan cameras for track inspection; KarTrak barcodes on trains were an early commercial application. Two camps emerged: those who enjoyed the practical/artistic hack and those who noted existing industrial use. A mention of using IMU + GNSS carrier-phase recordings for better 3D reconstruction was noted.