Automatic colorization for Thangka sketch-based paintings

Thangka is a kind of ancient painting that originated from Tibetan culture. Considering its value in cultural and historical fields, digital protection and restoration of Thangka images are important. In this paper, we propose an automatic colorization framework for a Thangka sketch. First, we propose a network structure with a feedback generator to restore the true color of a Thangka painting based on semantic matching. Second, we design a color gradient algorithm for Thangka coloring. Finally, we construct an automatic coloring framework for Thangka paintings that supports user customization. The experimental results show that the algorithm has a highly accurate response to a user's selection process. Compared with traditional methods, the proposed method improves the image quality by 22.3% on average. The data for our approach are publicly available at https://github.com/wangfubo123/SMAC-CGAN.