Computer-assisted coloring and illuminating based on a region-tree structure
Renata Gomes Lemos do Nascimento, Fabiane da Silva Queiroz, Allan Rocha, Tsang Ing Ren, Vinícius M. Mello, Adelailson Peixoto · SpringerPlus · 2012
Colorization and illumination are key processes for creating animated cartoons. Computer assisted methods have been incorporated in animation/illustration systems to reduce the artists' workload. This paper presents a new method for illumination and colorization of 2D drawings based on a region- tree representation. Starting from a hand-drawn cartoon, the proposed method 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, combined with an interpolation method that accurately computes a normal mapping for the illumination process. Different operators for curve and region attributes can be applied independently, obtaining different rendering effects.