THE ANALYSIS OF ROAD SLIDE SLOPES USING RC HELICOPTER 
PHOTOGRAMMETRIC SYSTEM 
Jang, Ho Sik a ’ , Kim, Cha Kyum b , Lee, Jong Chool c , Lee, Young Dae d , Oh, Hyun Woo e 
‘‘Department of Naval Architecture and Civil Engineering, Gyeongnam Provincial Namhae College, Gyeongnam, 
South Korea - gpsjhs@namhae.ac.kr 
b Department of Naval Architecture and Civil Engineering, Gyeongnam Provincial Namhae College, Gyeongnam, 
South Korea - kick@.namhae.ac.kr 
"Division of Construction Engineering, Pukyong National University, Busan,South Korea - jclee@pknu.ac.kr 
d Division of Construction Engineering, Pukyong National University, Busan, South Korea- ydlee@pknu.ac.kr 
"Division of Construction Engineering, Pukyong National University, Busan, South Korea - nywohy31@nate.com 
Commission V, WG IV/3 
KEY WORDS: RC Helicopter, Aerial Photography, Point Cloud Data, Slide Slopes, Non-Contact Measuring 
ABSTRACT: 
In this study, 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 
than the existing measuring technology, and the mean values were 0.056m in the x-axis direction, 0.082m in the y-axis direction, and 
0.066m in the z-axis direction. 
1. INTRODUCTION 
In order to manage and maintain the existing slopes in designing 
structures such as roads, railways, watercourses, and dams in 
the area of land development, the slides that are inevitably 
opened, and the slopes that are already completed, two methods 
to construct the data of slopes are used: the existing survey 
method using total station and the latest method using laser 
scanner to obtain numerous point clouds. However, the former 
includes a method to approach collapsed slopes taking risks 
with actual measurement and interpolation and a method to 
indirectly obtain the data from collapsed slopes with no-target 
total station. However, they have the danger in approaching a 
collapsed slope and a problem with accurate data collection due 
to selectively obtaining the needed data. The latter is advanced 
equipment that is much used in construction, architecture, and 
cultural assets. Even though it can obtain 
accurate and numerous point cloud data, it is expensive 
equipment inappropriate to be employed in actual field. Also, 
the equipment is large and heavy so it is difficult to move it. 
Therefore, in order to address these problems, this study aims to 
explain the method to obtain the data of slide slopes from aerial 
photos taken without approaching the collapsed slide slope by 
using photogrammetric system of RC helicopter, which is 
actively researched in South Korea. 
2. RC HELICOPTER PHOTOGRAMMETRY SYSTEM 
Regarding to RC helicopter photogrammetric system, recently 
as the width of demand on leisure activities is gradually 
increased along with the execution of the five-day workweek in 
the domestic, the leisure cultures using the instruments which 
are enjoyable in the suburbs are being activated. Especially, as 
the cultures using the instruments controled by radio are 
introduced along with the advance of computer simulation 
technology, these are being frequently utilized to photograph the 
bird's-eye-view in the area of engineering works, architecture 
and cultural properties, etc in the domestic also. 
This RC helicopter photogrammetric system means the body of 
small helicopter controled by radio, Gimbal Mount equipment 
making it possible to photograph as equipping the camera on the 
skid of the prop of helicopter and the system controling to 
photograph the images that the captured scenes while the 
helicopter moves are photographed through the monitor on the 
ground like the Figure 1 and Table 1. The vibration or the 
rolling and the pitching, the reason of the tremor of camera, can 
be controlled with over 1/250 seconds as the shut speed of 
camera. Accordingly, this system photographed with the shut 
speed of camera of l/4000seconds 
Especially, RC helicopter in this study is seemed to be excellent 
at the aspect of economic efficiency, mobility and speed as it 
can be directly controlled after the piloting technology being 
learned within the short period along with the low expense of 
the plane and the advance of computer simulation technology. 
And as the body of helicopter used in this study is controlled by 
the radio, the control from the ground can be said to be 
unlimited but it makes it possible to photograph while keeping 
the flying altitude at the safe distance(about 200m) where the 
shape of plane can be confirmed with the eyes of controller. The 
stabilizer was equipped to help the convenience of photograph 
and to make the level flight at the high altitude by the beginners 
and the highly applied controllers also easy and makes the