[theoh]

This may be obvious to some, but the software already knows what's on the colouring book page. It has a predefined model of the character, so it just applies a texture mapping algorithm (with some guessing to colour the back side of the character).

[waleedamer]

I actually just started reading the abstract and let out a deep sigh. It's still impressive but no longer mind-blowing unfortunately.

[theoh]

Maybe TEDDY from a few years ago is more like what you're looking for: https://m.youtube.com/watch?v=e2H35SlLmUA