Color by numbers: Interactive structuring and vectorization of sketch imagery

Abstract

We present a novel, interactive interface for the integrated cleanup, neatening, structuring and vectorization of sketch imagery. Converting scanned raster drawings into vector illustrations is a wellresearched set of problems. Our approach is based on a Delaunay subdivision of the raster drawing. We algorithmically generate a colored grouping of Delaunay regions that users interactively refne by dragging and dropping colors. Sketch strokes defned as marking boundaries of diferent colored regions are automatically neatened using Bezier curves, and turned into closed regions suitable for flls, textures, layering and animation. We show that minimal user interaction using our technique enables better sketch vectorization than state of art automated approaches. A user study, further shows our interface to be simple, fun and easy to use, yet efectively able to process messy images with a mix of construction lines, noisy and incomplete curves, sketched with arbitrary stroke style.