Line Scan Camera Image Processing for Train Photography

Usually the issue is they need rather still subjects, but in this case rather than the sensor doing a scanning sweep they're just capturing the subject as it moves by, keeping the background pixels static.

You can also get close in software. Record some video while walking past a row of shops. Use ffmpeg to explode the video into individual frames. Extract column 0 from every frame, and combine them into a single image, appending each extracted column to the right-hand-side of your output image. You'll end up with something far less accurate than the images in this post, but still fun. Also interesting to try scenes from movies. This technique maps time onto space in interesting ways.

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.

At first, I thought this explanation would make sense, but then I read back what I just wrote and I'm not sure it really does. Sorry about that.

As for RCD demosaicing, that's my next step. The color fringing is due to the naive linear interpolation for the red and blue channels. But, with the RCD strategy, if we consider that the green channel has full coverage of the image, we could use it as a guide to make interpolation better.

Like if the camera is $5k, in order to get that exposure time in full-field you would need to duplciate the hardware 800 times or whatever you wanted horizontal resolution to be. Thats alot of zeros for a single camera

OCT is a technique which uses IR to get "through" tissue using beam in the near infrared (roughly 950 nm, with a spread of roughly 100 nm). The return is passed through interferometer and what amounts to a diffraction grating to produce the "spread" that the line camera sees. After some signal processing (FFT is a big one), you can get the intensity at depth. If you sweep in X,Y somehow, usually deflecting the beam with a mirror, you can obtain a volumetric image like an MRI or sonogram. Very useful for imaging the eye, particularly the back of the retina where the blood vessels are.

You can get some cool distortions at very slow speeds, but at car or train speeds you won’t see anything

Nankai 6000 series, Osaka:

https://i.dllu.net/nankai_19b8df3e827215a2.jpg

Scenery in France:

https://i.dllu.net/preview_l_b01915cc69f35644.png

Marseille, France:

https://i.dllu.net/preview_raw_7292be4e58de5cd0.png

California:

https://i.dllu.net/preview_raw_d5ec50534991d1a4.png

https://i.dllu.net/preview_raw_e06b551444359536.png

Sorry for the purple trees. The camera is sensitive to near infrared, in which trees are highly reflective, and I haven't taken any trains since buying an IR cut filter. Some of these also have dropped frames and other artifacts.