Affiliation:
1. Carnegie Mellon University
2. Amherst College
3. California Institute of Technology
4. Université de Montréal
5. Boston University
Abstract
AbstractState‐of‐the‐art methods for line drawing vectorization rely on generated frame fields for robust direction disambiguation, with each of the two axes aligning to different intersecting curve tangents around junctions. However, a common source of topological error for such methods are frame field singularities. To remedy this, we introduce the first frame field optimization framework guaranteed to produce singularity‐free fields aligned to a line drawing. We first perform a convex solve for a roughly‐aligned orthogonal frame field (cross field), and then comb away its internal singularities with an optimal transport–based matching. The resulting topology of the field is strictly maintained with the machinery of discrete trivial connections in a final, non‐convex optimization that allows non‐orthogonality of the field, improving smoothness and tangent alignment. Our frame fields can serve as a drop‐in replacement for frame field optimizations used in previous work, improving the quality of the final vectorizations.
Funder
Masason Foundation
Natural Sciences and Engineering Research Council of Canada
Fonds de recherche du Québec – Nature et technologies
Subject
Computer Graphics and Computer-Aided Design