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 APPLICATION OF 3D LASER SCANNING IN THE PROTECTION OF GROTTOES 
AND CARVINGS IN CHINA 
Li Yumin?, Zhang Rong?, Zheng Yu* 
* Beijing Tsinghua Urban Planning &Design Institute, Cultural Heritage Conservation Centre, Beijing, P.R.China 
KEY WORDS: 3D laser scanning, grottoes and carvings, protection, demonstration, interpretation 
ABSTRACT: 
With the development of 3D laser scanning technology, it has been widely used in the recording and conservation of stone cultural 
relics. A lot of grottoes and carvings in national key cultural heritage protection units in Shanxi, Gansu and Sichuan areas of China 
have been scanned by 3D laser scanner in their protection projects. In this paper, via these 3D laser scanning projects of the grottoes 
and carvings, technical essentials of indoor and field work in the 3D laser scanning technology of stone cultural relics are 
summarized. At the same time, different devices were selected and different device parameters were set on the basis of 
characteristics of specific relics. Thus the current situation of the relic was recorded precisely with the least storage space and the 
shortest working time. At last, digital results including 3D models, 2D drawings, the videos for exhibition and etc with powerful 
operability which meet different needs are obtained based on the original point cloud. This paper can provide some beneficial 
reference and experience for recording and conservation of the grottoes and carvings relics in the future. 
1. THE CURRENT SITUATION OF STONE 
CULTURAL RELICS IN CHINA 
1.1 Introduction 
As the eastward of Buddhism, the cutting of grottoes have risen 
all over China, especially in the the Yangtze river basin, Yellow 
river basin, the silk road and so on. According to statistics, just 
the number of stone cave temple and the national key cultural 
relics’ protection units of grotto has reached to 286. The cutting 
of grottoes began from Han dynasty, was prevalent in Northern 
Wei, Sui and Dang dynasties, song dynasty and continued to 
Ming and Qing dynasties. The grottoes are rich in content, such 
as buildings, statues, murals, relief and so on. These relics are 
Valuable Information for research on social economy, politics, 
religion, art and architectural engineering of China !!!. 
1.2 The problem of grottoes’ current situation 
Through a long time, much of stone cultural  relics 
were badly damaged. The main reason include following 
aspects: 
1. Erosion of natural forcing 
Rainfall and groundwater gave rise to water seepage and damp, 
Thus Caused microbial disease and Surface suffused with salt, 
even caused missing of detail feature and dropping of colour. 
On the other hand, geological disaster might give rise to damage 
of statues and wall paintings. 
2. Change of the environment 
As urban construction and development of modern industry, 
cultural relics in the grotto were affected by the environment. 
For instance, Acidic floating dust, floating dust and the change 
of environmental humidity could accelerate the weathering of 
grottoes statues. 
3. Man-made sabotage 
From the 19th century to the 20th century, lots of grotto relics 
had been lost overseas. In addition, many grotto relics were 
stolen by criminals in recent years. 
705 
Because a complete recording is the most fundamental and 
reliable basis forthe work of protecting cultural relics, a 
fundamental recording for current situation of grotto relics is 
necessary before all the problems are solved. 
situation of 
1.3 Recording method for current 
Grotto Relics 
The investigation on grotto relics in China has begun in the 
1930s Pl, The original surveying method for grottoes depended 
on the manual surveying. The advantage of this method is 
simple and cheap, but it is time-consuming and has low 
efficiency. 
As the development of the technology on surveying and 
compute, close range photogrammetric is more and more used 
in surveying of Grotto Relics. This can make up the difference 
of manual surveying and improve the surveying precision and 
efficiency, however, because of the lack of expression, this 
method can cause a loss of detail information. 
In recent years, a new type of recording technology for 
three-dimension information-3D laser scanning is introduced to 
protection work for grotto relics. 3D laser scanning system is 
measuring instrument for three-dimension coordinate with many 
kinds of high-tech. It adopts non-contact and active measuring 
method, can acquire high-precision three-dimension data and 
can scan any type of object. At the same time, it is not restricted 
by light and can quickly acquire the surface information. 3D 
laser scanning has a wide application prospect in protection 
work for grotto relic . 
2. THE THEORY AND PARAMETER SETTING OF 3D 
LASER SCANNING 
2.1 The theory of 3D laser scanning 
According to the location principle of 3D laser scanning, as 
shown in Figure 1, Origin of coordinates is located in the centre