Style2Paints Research → [Zhang et al. 2020]
Generating Digital Painting Lighting Effects via RGB-space Geometry

ACM Transactions on Graphics (Presented at SIGGRAPH), January 2020

Lvmin Zhang, Edgar Simo-Serra, Yi Ji, and Chunping Liu
Examples of digital paintings and lighting effects created by professional artist manually. Digital painting artists are good at drawing lighting effects in various styles. From the perspective of computer graphics, can we generate artistic lighting effects on these drawn pictures to complement the current lighting composition workflow? Maybe we can first observe the artists' drawing process for some inspiration ......
Abstract

We present an algorithm to generate digital painting lighting effects from a single image. Our algorithm is based on a key observation: artists use many overlapping strokes to paint lighting effects, i.e., pixels with dense stroke history tend to gather more illumination strokes. Based on this observation, we design an algorithm to both estimate the density of strokes in a digital painting using color geometry, and then generate novel lighting effects by mimicking artists' coarse-to-fine workflow. Coarse lighting effects are first generated using a wave transform, and then retouched according to the stroke density of the original illustrations into usable lighting effects.
Our algorithm is content-aware, with generated lighting effects naturally adapting to image structures, and can be used as an interactive tool to simplify current labor-intensive workflows for generating lighting effects for digital and matte paintings. In addition, our algorithm can also produce usable lighting effects for photographs or 3D rendered images. We evaluate our approach with both an in-depth qualitative and a quantitative analysis which includes a perceptual user study. Results show that our proposed approach is not only able to produce favorable lighting effects with respect to existing approaches, but also that it is able to significantly reduce the needed interaction time.
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Citation

Lvmin Zhang, Edgar Simo-Serra, Yi Ji, and Chunping Liu
"Generating Digital Painting Lighting Effects via RGB-space Geometry."
ACM Transactions on Graphics, January 2020.

BibTeX

@article{Zhang2020,
   author = "Lvmin Zhang and Edgar Simo-Serra and Yi Ji and Chunping Liu",
   title = "Generating Digital Painting Lighting Effects via RGB-space Geometry",
   journal = "ACM Transactions on Graphics",
   year = "2020"
}