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Texte & 
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ISci, Jari 
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' Finland, 
e project 
oducts. 
KEY WORDS: digital, photogrammetry, cultural heritage, geomorphology, conservation, laser scanning, close range, stone 
monuments 
ABSTRACT: 
In Korea, there are many stone monuments, such as scarvings on the rock slope. Some of stone scarvings are under severe 
weathering and others are often jointed, both of which are harmful to the conservation of important stone monuments. Long term 
conservation of stone scarvings on stone surface requires exact geometry of each jointed rock blocks and then it could be possible to 
assess the safety and durability of such rock mass on the slope surface. In this study, laser scanning and digital photogrammetry 
using digital camera were conducted to acquire digital surface model of rock surface. 
Comparison of the results with remote sensing techniques shows that data quality strongly depends on the type of each rock and the 
pattern of joints developed on the rock surface. 
1. INTRODUCTION 
The conservation of stone monuments like scarvings and 
paintings on the rock slope is directly implicated in the stability 
of base rock. So it is important to measure fracture orientation 
at exposed rock faces for prediction and prevention of 
deformations. 
Conventional methods to measure it are using the compass- 
inclinometer device that is convenient and easy to operate. But 
operator has to test in physically contact with the rock and it 
cannot ensure the safety of the operator. And scarvings or 
printings on the rock slope can be impaired. 
Recently, there was a report on the measurement of the 
discontinuity from 3D model of rock surface generated by 
remote sensing techniques such as laser scanning (Slob et. Al., 
2002) and digital stereo photogrammetric technique. 
Using digital surface model (DSM) of stone monuments has 
following advantages : 
•To test the stability of base rock with safety. 
•Not to impair the cultural heritage during the measurment. 
•To measure the deformed shape by comparing with digital 
surface model generated at later time. (Baltsavias et. Al., 
2001) 
•Usage for the restoration after deformation. 
•To re-create 3D virtual cultural heritages model . 
In this study, attempts were made to generate the digital surface 
model of rock slope using laser scaning and digital stereo 
photogrammetric technique and examine a suitability of the 
photogrammetry for the rock slope by overlapping the DSM 
generated by laser scanning. 
This paper is intended to compare the digital photogrammetric 
technique with laser scanning to generate 3D model of rock. It 
could be argued what the merits and demerits the method has. 
Laser scanning and digital stereo photogrammetry are applied 
the target area in Figure 1. If one uses the traditional approach, 
as compass-inclinometer device, it seems hard to get the 
objective result because the test sample is rough and wavy. The 
site which looks triangular shape was selected. It was 
characteristic wedge failure region. 
¡) 
Figure 1. Image of rock face (white circular marks on the rock 
surface are targets for control) 
2.1 Laser Scanning 
Laser scanning was carried out for obtaining DSM from an 
exposed rock mass. 
Corresponding author. 
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