Facial expression animations

Hey guys,

I wanna create natural, realistic, believable facial expressions for my models.

So, the way I’m thinking in doing that is watching and analyzing carefully tons of videos of people doing all sorts of weird things with their faces, like smiling, laughing etc. So I can learn how the muscles of the face move in all its details.

Then I could use that old technique called rotoscope to create nice facial expressions to my characters.

So what do you think about that? In your experience, what technique of learning and applying facial expressions would produce the best results? Thank you.