t‐Regina: Data‐driven Authoring of Free‐form Registration for Cartoon Character Sprites

This paper proposes t‐Regina, a novel iterative scheme that automates the manipulation of grid handles in free‐form deformation (FFD) for deformable registrations of cartoon character sprites. First, we build a data‐driven FFD (dFFD) that enables users to handle locations of FFD handles from lower‐dimensional parameters. To prepare training data, we implement an FFD‐based puppet tool and recorded the user‐designed locations of grid handles. Second, we iteratively optimize the parameters of dFFD by using a locally optimal block matching algorithm with almost‐uniform sampling strategies. t‐Regina is effective and easy to integrate into existing drawing systems. This paper shows some examples of deformation results to demonstrate the robustness of t‐Regina.