Stroke Correspondence by Labeling Closed Areas

TL;DR

This paper introduces a new method for estimating stroke correspondences in hand-drawn animation frames by analyzing closed areas, reducing manual effort and improving efficiency.

Contribution

The method estimates stroke correspondences directly from raster images without vectorization, using shape, depth, and connection features of closed areas.

Findings

Effective in estimating stroke correspondences

Reduces manual annotation effort

Outperforms conventional approaches in user study

Abstract

Constructing stroke correspondences between keyframes is one of the most important processes in the production pipeline of hand-drawn inbetweening frames. This process requires time-consuming manual work imposing a tremendous burden on the animators. We propose a method to estimate stroke correspondences between raster character images (keyframes) without vectorization processes. First, the proposed system separates the closed areas in each keyframe and estimates the correspondences between closed areas by using the characteristics of shape, depth, and closed area connection. Second, the proposed system estimates stroke correspondences from the estimated closed area correspondences. We demonstrate the effectiveness of our method by performing a user study and comparing the proposed system with conventional approaches.