2015/09/10 by Jianchao Tan, Tan, Jianchao, Jyh‐Ming Lien +3
Computer Science · #65D18 #Advanced Vision and Imaging #Computer Graphics and Visualization Techniques #Digital Image Processing Techniques #FOS: Computer and information sciences #Graphics (cs.GR) #I.3.7 #I.4.6
paper · pdf · doi:10.48550/arxiv.1509.03335
openalex publication_date 2015/09/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In digital painting software, layers organize paintings. However, layers are not explicitly represented, transmitted, or published with the final digital painting. We propose a technique to decompose a digital painting into layers. In our decomposition, each layer represents a coat of paint of a single paint color applied with varying opacity throughout the image. Our decomposition is based on the painting's RGB-space geometry. In RGB-space, a geometric structure is revealed due to the linear nature of the standard Porter-Duff "over" pixel compositing operation. The vertices of the convex hull of pixels in RGB-space suggest paint colors. Users choose the degree of simplification to perform on the convex hull, as well as a layer order for the colors. We solve a constrained optimization problem to find maximally translucent, spatially coherent opacity for each layer, such that the composition of the layers reproduces the original image. We demonstrate the utility of the resulting decompositions for re-editing.