International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XL-5/W2, 2013 
XXIV International CIPA Symposium, 2 — 6 September 2013, Strasbourg, France 
the way of the statistical disease in the plane. To reduce the 
statistical error, the disease information can be defined directly 
for triangle patch on the model and the area of disease can be 
measured conveniently by the way of triangular grid model. In 
the plan of protection for thousand-buddha cliff in Guangyuan, 
as shown in Figure3 , the statistical area of disease can be 
acquired exactly and the distribution of disease can be displayed 
directly by 3D laser scanning and defining the type of disease 
on every triangle patch. 
  
  
  
  
  
  
  
  
  
  
Disease Disease 
type area 
exfoliation 13.74m2 
blistering 2.38 m2 
deletion 3.56 m2 
waterlogging | 0.05 m2 
scratch 0.05 m2 
  
Lianhua cave in Qianfoya 
  
  
  
  
  
  
  
deletion 
waterlogging 
blistering 
scratch 
3 exfoliation 
  
  
    
Fig.3 Distribution of disease in lianhua cave 
3.2 Conservation measures taking 
Sometimes relics need to be reinforced in the structures, 
because of the instability of the rock mass. It is easy to find the 
direction, the angle and the distance of inclination of the relics. 
Furthermore, components falling from the relics can also be 
precise in the system. It provides a new effective method for 
relic’s protection. For example, the Jingmu tower in Sichuan 
province which was built in Song dynasty was badly damaged 
in the earthquake. As shown in Figure4. It leaned to the 
southwest more seriously and obviously. The stone component 
fell down from the top of the tower, at the same time breaking 
down the side of components of the tower [*. While simply 
having access to a clear and accurate record of 3D model with 
3D laser scanning of the tower helps the planner to determine 
the appropriate action for its protection. And it can also bring 
the fallen components back virtually which have fallen down in 
the system. As shown in Figure5 and Figure6. 
EN 
  
7 southward migration of 10mm 
* westward migration of 20mm 
southward migration o£ 
20mm 
southiward migration of 
£9 mm 
westward migranon of 
21 mm 
southward migration 
of 8 mm 
   
Fig.5 Migration of the tower after the 
earthquake 
Fig.4 Jingmu Tower in 
Sichuan 
707 
    
NO.4 component after earthquake [fallen components before earthquake 
NO.3 component 
NO.8 component 
NO.1 component 
NO.6component 
NO.5coniponent 
  
    
   
d 
NO.13 
  
Fig.6 The sketch of the restored jade 
3.3 Demonstration and Interpretation 
The data which is acquired by 3D laser scanning contains rich 
spatial information. It helps to provide many new ideas for the 
exhibition of cultural relics. 
Because of the construction of reservoir, most of statues and 
murals of Tiantishan grottos which is built during Northern 
Liang was relocated to somewhere else. The authenticity and 
integrity of Tiantishan grottoes were destroyed. As shown in 
Figure7 and Figure8. At present, the cultural connotation, 
historical information and value contained in these statues and 
murals either displayed in museum or in cavern of north shore 
of the reservoir cannot be interpreted and delivered well. As 
shown in Figure9. This manner can only be called preserving 
instead of protection. The research of virtual restoration was 
preceded by means of historical photos, grottoes shape data and 
3D laser scanning for these cultural relic. Because the color 
digital model of statues and murals was virtual restored 
according to the grottoes shape and the relationship of every 
part is established, the historical information can be experienced 
by the public completely and truly. As shown in Figurel0. 
   
   
  
Fig.7 NO.2 cave of Tianlongshan in 1922 
Fig.8 current cave 
  
Fig.9 the exhibition of statues from Tiantishan Cave