1. Master : Jun-Hao Chen Advisor : Dr. Hsin-Chih Lin Date : 2007/11/13 Computer-Generated Chinese Color Ink Paintings Journal of the Chinese Institute of Engineers Vol.29, No.6, pp.1041-1050 (2006) Der-Lor Way, Wei-Jin Lin, Zen-Chung Shih

2. Outline Introduction Previous Work Framework Properties of Chinese Ink Painting Motion of Water Ink Diffusion Colour Presentation Interactive Painting System Conclusions Future Works 2007/11/13 2 Computer Graphics and Interactive Techniques Lab.

3. Introduction Western Paintings v.s. Chinese Ink Painting Small(1990) Proposed a parallel approach to derive the action of pigment and water on paper fibers Curtis et al.(1997) Employed a more sophisticated paper model to simulate watercolors more realistically. 2007/11/13 3 Computer Graphics and Interactive Techniques Lab.

4. Previous Works Wong and Ip (2000) Modeled a calligraphy brush as an inverted cone Strassmann (1986) Described the hairy brush as a 1D array of bristles Jinatae Lee (1999) Presented a model for elastic bristles governed by Hooke’s law Guo and Kunii (1991) First addressed ink diffusion ( 墨绘 ) 2007/11/13 4 Computer Graphics and Interactive Techniques Lab.

5. Previous Works Zhang et al. (1999) Presented a 2D simple cellular automaton-based simulation model ink behavior Lee (2001) Rendered black ink paintings that applied new paper and ink diffusion models 2007/11/13 5 Computer Graphics and Interactive Techniques Lab.

6. Previous Works No mechanism has been presented to simulate the blending of two or more different brush strokes and color diffusion Chu and Tai (2004) Designed a deformable brush model as a single tuft Also investigated three ink-depositing variation Chu and Tai (2005) Simulate ink painting in real time with lattice Boltzmann equation 2007/11/13 6 Computer Graphics and Interactive Techniques Lab.

7. Previous Works Way and Shih (2001,2002) Implemented the effects of brush strokes and developed model that combines two mechanism Way et al., (2003) Simulating the diffusion of black ink in different types of paper 2007/11/13 7 Computer Graphics and Interactive Techniques Lab.

8. Previous Works This paper … Simulate the physical behavior color diffusion, can thus generate strokes that exhibit feathery effects Can blend two strokes with different thickness Users can apply a high-quality ink diffusion model to generate a Chinese ink painting 2007/11/13 8 Computer Graphics and Interactive Techniques Lab.

9. Properties of Chinese Ink Painting Four treasures Brush Ink stick Paper Ink stone Fluffy and blurred Capillary phenomenon 2007/11/13 9 Computer Graphics and Interactive Techniques Lab. Ink Diffusion Effect

10. Properties of Chinese Ink Painting Paper cell Regular fiber mesh Irregular distributed fiber mesh Absorbency 2007/11/13 10 Computer Graphics and Interactive Techniques Lab.

11. Properties of Chinese Ink Painting Water Particles 2007/11/13 11 Computer Graphics and Interactive Techniques Lab.

12. Properties of Chinese Ink Painting Carbon Particles Brownian motion 2007/11/13 12 Computer Graphics and Interactive Techniques Lab.

13. Properties of Chinese Ink Painting Carbon Particles Filter Effect if(Carbon_Diameter > Hole_Diameter(p)) then Carbon_Position ← p else Carbon_Position ← Water_Outflow_Direction(p) 2007/11/13 13 Computer Graphics and Interactive Techniques Lab.

14. Properties of Chinese Ink Painting Carbon Particles 2007/11/13 14 Computer Graphics and Interactive Techniques Lab.

15. Motion of Water Factors that dominate the flow of water Gradient of water between neighboring papels Absorbency of neighboring papels Paper texture of neighboring papels Inertia of water 2007/11/13 15 Computer Graphics and Interactive Techniques Lab.

16. Motion of Water Gradient Based on Brownian motion 2007/11/13 16 Computer Graphics and Interactive Techniques Lab.

17. Motion of Water Absorbency Newton’s Second Law of Motion 2007/11/13 17 Computer Graphics and Interactive Techniques Lab.

18. Motion of Water Paper texture Papers with different distributions of fibers have different textures 2007/11/13 Computer Graphics and Interactive Techniques Lab. 18

19. Motion of Water Inertia Newton’s First Law of Motion Probabilities of inertia : Identify the directions of water flow 2007/11/13 19 Computer Graphics and Interactive Techniques Lab.

20. Motion of Water Total Probability 2007/11/13 20 Computer Graphics and Interactive Techniques Lab.

21. Ink Diffusion Continuous and time-dependent Evaporation of water Absorption of ink remaining on the surface of the paper 2007/11/13 21 Computer Graphics and Interactive Techniques Lab.

22. Ink Diffusion Ink Diffusion Schema 2007/11/13 22 Computer Graphics and Interactive Techniques Lab.

23. Ink Diffusion Evaporation 2007/11/13 23 Computer Graphics and Interactive Techniques Lab.

24. Colour Representation Colors of Ink and Color Pigment Kubelka-Munk (KM) Model 2007/11/13 24 Computer Graphics and Interactive Techniques Lab. Absorption coefficient K, Scattering coefficient S

25. Colour Representation Reflectance R Transmittance T 2007/11/13 25 Computer Graphics and Interactive Techniques Lab.

26. Colour Representation Two layers 2007/11/13 26 Computer Graphics and Interactive Techniques Lab.

27. Colour Representation Color Mixing 2007/11/13 27 Computer Graphics and Interactive Techniques Lab. (a) The real image. (b) The simulated image

28. Colour Representation The Water Effect on Paper Alpha mask 2007/11/13 28 Computer Graphics and Interactive Techniques Lab.

29. Interactive Painting System System Architecture 2007/11/13 29 Computer Graphics and Interactive Techniques Lab.

30. Interactive Painting System System AMD 1.4GHz CPU 256 MB Ram C++ OpenGL 2007/11/13 30 Computer Graphics and Interactive Techniques Lab.

31. Interactive Painting System Results 2007/11/13 31 Computer Graphics and Interactive Techniques Lab. Painting time: 1 hour

32. Interactive Painting System Results 2007/11/13 32 Computer Graphics and Interactive Techniques Lab. Painting time: 2 hours

33. Interactive Painting System Results 2007/11/13 33 Computer Graphics and Interactive Techniques Lab.

34. Conclusions Expression of a mixture of different kinds of brush strokes, such as those two wet brushes. The resulting color ink paintings are very realistic Users can apply parameters to control local and global variations and achieve their desired effects 2007/11/13 34 Computer Graphics and Interactive Techniques Lab.

35. Future Works The glue quantity added to the paper Mineral based pigments 2007/11/13 35 Computer Graphics and Interactive Techniques Lab.

36. Jun-Hao Chen zidane0615@gmail.com Thank you for listening !!