The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
3. THE METHOD OF FIELD OBSERVATION AND 
ANALYSIS 
To obtain the information on road cut failure slope, as seen in 
the Figure 4, this study investigated the slope of a part of STA. 
2+720 of the 2nd section of works of Pusan-Ulsan Expressway, 
Gijang-eop, Gijang-gun, Pusan, South Korea which is the 
topography composed of the andesite belonged to the kind of 
volcanic rock and the inferior ground such as the weathering 
soil or the weathering rock, etc. and of which the 1st collapse 
was occurred from the sliding by localized heavy rain occurred 
from July to September in 2005 and the 2nd collapse was 
additionally occurred by localized heavy rain occurred recently. 
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Figure 6. Ortho 3D Model 
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Figure 4. Road Cut and Failure Slope 
This study, as the method to obtain the information of the failure 
slope with such danger, performed the control survey of the 
slope by total station without target and obtained the images of 
failure slope through the hovering by the stabilizer at the 
altitude of about 40m as using RC helicopter photogrammetric 
system like the Figure 5. 
And the centers of obtained 2 images were united to make 3D 
model as the-first and then make the precise second model. 
After the characteristic points were minutely adjusted, the ortho 
3D model was made as inputting the coordinates of control 
survey with total station without target, which was appeared as 
per the Figure 6. 
And the Figure 7 is to be appeared in the form of CAD file as 
drawing the scope of failure slope and the cross section of each 
slope and the Figure 8 is to be appeared as overlapping it with 
the file of the Triangulated Irregular Network(TIN) along with 
the data, which appeared the method to obtain the information 
of failure slope. 
Figure 5. The Hovering by the Stabilizer 
Figure 7. The Cross Section of Each Slope 
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Figrue 8. Triangulated Irregular Network 
4. CONCLUSION 
According to the results of slope data obtained with a non- 
contact measuring method of aerial photography by using the 
photogrammetric system of RC helicopter without approaching 
the slope collapsed by sliding, first, the photogrammetric 
system of RC helicopter allowed mobility, accessibility, and 
hovering flight so it was possible to obtain images of the areas 
that cannot be approached due to risk of collapse with the non- 
contact photographing method. Second, from the obtained 
images, it was possible to generate the three-dimensional spatial 
information in the form of point-cloud data regarding the 
collapsed slopes with the 3D image matching. This high- 
precision point-cloud data could be used as important positional 
data for safety of the collapsed slopes on roads. Third, this 
photogrammetric system makes it possible to obtain the high- 
precision information of the collapsed slopes in shorter time 
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