The problem isn't just approximate positioning of lines, but radically different artistic styles and amounts of shading and detail. Is someone's hair made of one line, five lines, or 100 lines? Does a face have 3 simple lines or 50 little lines that give a sense of skin texture?
Distance fields would work great for font outlines, but not for translating movie frames.
Oh, I don't know. How well does it have to work? If anything I'm suddenly very curious what kind of results you'd get from converting line art to distance fields, averaging/interpolating, and converting back. Maybe I'll write some code...
