Recently, a drone is being utilized in diverse fields such as transportation, communication, IT, agriculture, broadcasting etc. as well as in military. Especially, a camera that is mounted onto a drone is one of major functions of a drone, and key technologies such as a control technology, a technology of avoiding a collision, a sensing technology and a data link technology etc. are being developed in order to acquire stabilized flying and images with high resolution. In this study, a surface of discontinuity of a rock was investigated by using images shot by a drone for the area that is not accessible by an investigator at the cutting slope of a rock with its height of 94m. Besides, the displacement more than 100mm at a rock area has been observed and comparatively analyzed by utilizing images shot by a drone for about 5 months at the interval of 2 weeks. This played an important role in selecting a dangerous section and establishing a plan for reasonable repairs, reinforcement and maintenance by sensing deformation of the ground at a rock slope such as falling rocks, relaxation, cracks etc.
Since a drone is recently spotted as the next-generation growth industry and rapidly spreads into the industrial and civil markets from military industry, it can be said that each country in the world gets into a frame of fierce competition to occupy a drone industry in advance. Also in the Korean government, its potential growth possibility of a drone market receives attention and establishment of infrastructure and related policies are being progressed to revitalize and foster a drone industry into a new growth drive industry of a nation such as implementation of a pilot project at each diverse industry such as unmanned flying logistics, construction, disaster, environment, monitoring etc. (Kim, S. H. et al., 2016).
A camera that is mounted onto a drone is one of major functions of a drone, and key technologies such as a control technology, a technology of avoiding a collision, a sensing technology and a data link technology etc. are being developed in order to acquire stabilized flying and images with high resolution. In particular, a gimbal mount camera that can maintain a perpendicular state regardless of vibration or rolling is one of major functions that can acquire images with high quality. Even a low-end drone has been equipped with a camera with high resolution of 4k UHD (4k Ultra High Definition, 3840 × 2160) or which can be detachable so its utilization in a variety of fields gets higher and higher. Since images of a drone have excellent preciseness, they can be efficiently used in surveying topographies or facilities. It is useful for 3-dimension survey for wide areas such as a quarry and earth work sites (Oh J. H. et. al, 2017). Kim, S. J. et al., 2017, suggests that if its preciseness is improved, its utilization will get higher since there was a difference of 1.2∼1.5% as a result of comparing variation of volume of earth works by dates with the measured value by a person through RTS by making a 3-dimension numerical map utilizing a drone.
Besides, since a point requiring repairs can be found exactly and promptly upon checking a bridge, the required time and costs for the past person directly to find a point to repair can be saved (Seo, C. W. et. al, 2017). It is also expected to have an effect of saving the budget through retrenchment of manpower and the period in cadastral investigation (Lee Y. C. et al., 2016).