1. College of Computer Science and Engineering
A Case Study of Virtual Museum: Reconstruction and Restoration of Dunhuang Caves in China
Jiaoying Shi
State Key Lab of CAD&CG
College of Computer Science and Engineering
Zhejiang University
2003.8

2. Contents Introduction of Dunhuang Mogao Caves
Reconstruction of Dunhuang Mogao Caves
Restoration of the Murals in Dunhuang Mogao Caves

3. 1. Introduction of Dunhuang Mogao Caves
It’s located in North-West desert area of China
Start excavating in Jin Dynasty(336 A.D), 1600 years old.

4. There still exist 492 intact caves, more than 2400 painted sculptures, over square meter murals and wood architectures of Tang and Song Dynasty
murals
architectures
painted sculptures

5. Named as World History and Culture Heritage by UNESCO in 1987
UNITED NATIONS EDUCATIONAL SCIENTIFIC AND CULTURAL ORGANIZATION
CONVENTION CONCERNING THE PROTECTION OF
THE WORLD CULTURAL AND NATURAL HERITAGE
The World Heritage Committee
Has inscribed
The Mogao Caves
On the world Heritage list
Inscription on this List confirms the exceptional
And universal value of a cultural or
Natural site which requires protection for the benefit
Of all humanity

6. The perennial invasion of sand blown by the wind has also done great damage to the treasury, thus putting it in severe danger.
In order to protect the Mogao Caves furthermore, today a severe measure of limiting the visitors number is taken by the local administrator.
So it is very urgent to build a virtual Museum of Dunhuang Mogao Caves to disseminate this World Cultural Heritage broadly.

7. 2. Reconstruction of Dunhuang Mogao Caves
Surveying the caves
Modeling the caves

8. Digitizing the murals photographing bracket Demo of Shooting
The criterion: well-proportioned lighting, parallel moving and partial overlaps

9. Mapping the murals onto the model

10. Mosaicing Images

11. Digitization of three-dimensional culture relics
Acquiring high-precision 3D models by 3D scanner
The model acquired by 3D scan

12. Digitization and modeling of outdoor scene 12
Take photos of out-door scene in a fixed point
Adjusting and mosaicing

13. Demo1: The navigation of Dunhuang Mogao Caves

14. Demo2: The navigation of Outdoor Scene of Dunhuang Mogao Caves

15. 3. Restoration of the Murals of Dunhuang Mogao Caves
The murals and sculptures in Dunhuang Mogao Caves have experienced color changes and impairment over 1600 years.
Introducing 3 techniques for virtual restoration of the mural color of Dunhuang Mogao Caves.

16. Reasoning Based on Scientific Rules Analogical Thinking Model
Virtual Color
Restoration
Reasoning Based on Scientific Rules
Analogical Thinking Model
Reasoning Based on experience knowledge

17. Reasoning Based on Scientific Rules
Chemical Color Changing Rule
Physical Color Changing Rule
Experience Knowledge
Computer
Color Changing Model
in Computer

18. Chemical Color Changing Rule
According to the chemical knowledge of Dunhuang researchers, we got the Chemical Color Changing Rule.
Changing gradually
Red Lead Oxide (PbO2 ) Oxygen(O2 ) Pb3O4

19. Physical Color Changing Rule
Over some time t, the color gradually changes or fades by covered dust.
It is essential a color mixing process of the mural’s color and dust’s color
Let mural color Cb （Rb，Gb，Bb）, dust color Cf （Rf，Gf，Bf）, the transparence of Cf be X%, then the mixing color is:
RGB(160,168,171) RGB(119,71,31) RGB(150,144,136)
25% Transparence

20. Analogous Thinking Model
Multi-layer mural
This is the inner layer
not been oxygenated
after outer layer fell off
The same dynasty
and cave
The unoxygenated color element
provide the source knowledge for
analogous reasoning

21. Reasoning Based on Experience Knowledge of the Dunhuang Artists and Researchers
The set of Dunhuang typical color of the Tang Dynasty:
Red
Yellow
Blue
Green
Brown
Gray
White
Golden

22. Reasoning Based on Experience Knowledge of the Dunhuang Artists and Researchers
Color Region Obtaining
Color Layering
Based on the set of typical color of Dunhuang
Edge Destination

23. Dunhuang Mural Color Virtual Restoration—Example of Color Faded Restoration
Refer the color well-protected mural image to restore
Source Image
Destination Image
Anology Reference

24. Dunhuang Mural Color Virtual Restoration—Example of Color Faded Restoration
According to the Chemical Color Gradually Changing Rule to restore
Source Image
Destination Image
Chemical Color Gradually Changing Rule

25. Dunhuang Mural Color Virtual Restoration—Example of Color Faded Restoration
Integrating Color
Faded Restoration
and Color Changed
Restoration
Source Image
Destination Image

26. Dunhuang Mural Color Virtual Restoration—Example of Color Faded Restoration
Using Created Pattern to restore faded region
Source Image
Destination Image
Created Pattern

27. Demo3: Dunhuang Mural Color Changing Process

28. Thanks!