A laser pointer at 2B FPS [video]

He did a good job on his setup, but I have to think that adding a spinning mirror would have made everything much faster and easier.

He could then capture an entire line quite quickly, and would only need a 1 dimensional janky mirror setup to handle the other axis. And his resolution in the rotating axis is limited only by how quickly he can pulse the laser.

Of course, his janky mirror setup could have been 2 off-the-shelf galvos, but I guess that isn't as much "content".

But I think he does capture an entire line quite quickly. As I understood it, he “scans” a line of pixels in seconds.

I think a spinning mirror would make it a lot harder. He's only moving the mirror after the "animation" finishes. So it's capture video, step by 1 pixel, capture video, step by 1 pixel, capture video, etc... He's replaying the scene ~1 million times, for 1 million unique single pixel 2 billion fps videos.

Are you suggesting it would be easier if the mirror spun at 2 billion revolutions per second?

Yeah, spinning at a constant rate with an encoder for triggering would probably be a bit more consistent. But potentially more of a mechanical headache. And he does need a pretty big mirror due to being limited by the amount of light he can focus on the sensor, I'm not sure that there are galvos available with such a large area (especially for a reasonable price).

Basically the constantly spinning motor would remove the complexity and slowdown of accelerating and decelerating it at the start and end of the motion. To capture a line, he's already scanning it across the scene and triggering the laser at specific points (when the encoder in the servo reaches certain values), if it was continuously rotating he could just do the same thing.

Though I don't think it would speed things up much, from what he was saying in one of the appendix videos on his second channel he doesn't do things like triggering the laser multiple times for each pixel to reduce noise because the bottleneck is copying the data off of the scope and it would stretch from hours to days to run.