Towards Preserving the Ephemeral: Texture-Based Background Modelling for Capturing Back-of-the-Napkin Notes

A back-of-the-napkin idea is typically created on the spur of the moment and captured via a few hand-sketched notes on whatever material is available, which often happens to be an actual paper napkin. This paper explores the preservation of such back-of-the-napkin ideas. Hand-sketched notes, reflecting those flashes of inspiration, are not limited to text; they can also include drawings and graphics. Napkin backgrounds typically exhibit diverse textural and colour motifs/patterns that may have high visual saliency from a low-level vision standpoint. We thus frame the extraction of hand-sketched notes as a background modelling and removal task. We propose a novel document background model based on texture mixtures constructed from the document itself via texture synthesis, which allows us to identify background pixels and extract hand-sketched data as foreground elements. Experiments on a novel napkin image dataset yield excellent results and showcase the robustness of our method with respect to the napkin contents. A texture-based background modelling approach, such as ours, is generic enough to cope with any type of hand-sketched notes.