Using the railway network as a flatbed scanner(philo.gay)
441 points by otherayden 3 days ago | 73 comments
tl;dr: A hobbyist mounted an industrial linear scanning camera (Basler ruL2048-19gm, ~19,000 lines/sec) out of trains and ferries to capture ultra-wide "flatbed scanner"-style images, using an accelerometer to correct for variable speed. Major challenges included integrating accelerometer data to derive velocity (GPS proved unreliable), handling parallax by tuning distance-per-pixel per segment, and fixing IR sensitivity and RGB channel misalignment on a color version. Postprocessing was rewritten in NumPy for a modular pipeline, and the resulting gigapixel TIFFs are served via OpenSeadragon tiles.
HN Discussion:
  • Sharing similar personal projects and prior experiments with line/slit scanning
  • Offering technical solutions to challenges mentioned in the article (image viewing, speed detection)
  • Appreciating the artistic and creative aspects of the project
  • Elaborating on the unique optical properties of line scan photography
  • Suggesting extensions or applications of the technique to other contexts