Stumbled upon an amazing SIGGRAPH paper on “Diffusion Curves: A Vector Representation for Smooth-Shaded Images”, at the Adobe ATL page : link. Given cartoon sketches represented as Bezier curves, with initial color values on either sides of the curves, they construct an image by letting the colors diffuse as governed by a Poisson equation. This can be used to rapidly create cartoon images and animations. The paper also solves the inverse problem, i.e. given an arbitrary smoothly shaded image, they determine the initial curves and color samples needed to vectorize the image.

Check out their cool demo here.

#### Diffusion Curves: A Vector Representation for Smooth-Shaded Images

Holger Winnemöller , Adobe Systems

Adrien Bousseau, INRIA, Grenoble, France

Alexandrina Orzan, INRIA, Grenoble, France

Pascal Barla, INRIA, Grenoble, France

Joelle Thollot, INRIA, Grenoble, France

David Salesin, Adobe Systems