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by throwaway87423 3337 days ago
> When a ball is about to hit your face your brain “can’t remember how to calculate the velocity and acceleration of the ball and predict that in 100ms it will impact your face and thus you need to send a signal for your hand to move to cover your face”.

It's likely doing optical flow calculations (much simpler), rather than integrating an ODE. Richard Dawkins apparently makes the same mistake about "catching a ball" in his book.

1 comments

By 'optical flow calculations' do you mean a linear extrapolation of the projected 'image-space' position of the ball?

If so, that seems like it would be insufficient since a thrown object doesn't move linearly, let alone its projection.

If not, then I'm curious what you're describing, and how it's much simpler than integrating an ODE?

Not quite. If you're interested take a look at,

https://youtu.be/eKaYnXQUb2g?t=6m10s

https://www.youtube.com/watch?v=iz9UVIo_ZUo&list=PL0AknDL1Vt...

Camera homography preserves straight-lines, but it also gives a heuristic to avoid obstacles. Apparently this is also how bees and birds navigate.