Colorization and Illumination of 2D Animations Based on a Region-Tree Representation

Colorization and illumination are key processes for creating animated cartoons. Computer assisted methods have been incorporated in animation/illustration systems to reduce the artists' effort. This paper presents a new strategy for illumination and colorization of 2D drawings based on a region-tree. Starting from a hand-drawn cartoon, it extracts geometric and topological information and builds a tree structure, ensuring independence among parts of the drawing, such as curves and regions. Based on this structure and its attributes, a colorization method that propagates through consecutive frames of animation is proposed, together with an interpolation method that accurately computes a normal mapping for the illumination process. Different operators on curve and region attributes can be applied independently, obtaining different rendering effects.