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Line scan camera image processing for train photography

(daniel.lawrence.lu)
448 points dllu | 1 comments | 23 Aug 25 16:09 UTC | HN request time: 0.001s | source
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jeffbee ◴[23 Aug 25 20:10 UTC] No.44998743[source]▶
Okay I was stumped about how this works because it's not explained, as far as I can tell. But I guess the sensor array has its long axis perpendicular to the direction the train is traveling.
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1. eschneider ◴[23 Aug 25 20:26 UTC] No.44998868[source]▶
You use a single vertical line of sensors and resample "continuously". When doing this with film, the aperture is a vertical slit and you continuously advance the film during the exposure.

For "finish line" cameras, the slit is located at the finish line and you start pulling film when the horses approach. Since the exposure is continuous, you never miss the exact moment of the finish.