5:15 PM - 6:45 PM
[HRE12-P03] Application of UAV to describe cracks in bedrock outcrops
Keywords:UAV, SfM, describing cracks
As a general method for describing cracks in bedrock outcrops, researchers set a survey line on the outcrops and directly measure cracks on the survey line. However, this method requires longer observation time and/or much more researchers for larger outcrop size. Additionally, physical damage to researchers could be considerable in cold climates since the outcrops are often located along rivers. Difficulties in access to the outcrops, such as river depth, river width, and vegetation, could also be concerned.
In recent years, unmanned aerial vehicles (UAVs) have been used to shorten on-site work time and replace work in difficult-to-reach places. UAVs are used in a wide variety of fields, including aerial photography, air transportation, agriculture, and surveying. In the field of surveying, the Geospatial Information Authority of Japan has prepared a surveying manual. A case study on the topographic interpretation using a UAV (Sugawara et al., 2021).
In this study, we tried description of cracks in bedrock outcrops using a UAV. The observations from up above or oblique above can enable to obtain three-dimensional information including direction and length of cracks. On the other hand, it is necessary to understand the accuracy of crack data specifically when crack size is small. We created three-dimensional point cloud data by SfM (Structure from Motion) technology from aerial images taken using a UAV, and measured strike and dip from the point cloud data using free software. In this presentation, we will introduce the method to read strike and dip from the point cloud data and show the result of comparison between the values from the aerial images and those measured in the field.
This study was funded by the Ministry of Economy, Trade and Industry, Japan as part of its R&D supporting programs “Establishment of Technology for Comprehensive Evaluation of the Long-term Geosphere Stability on Geological Disposal Project of Radioactive Waste (Fiscal Years 2023) (Grant number: JPJ007597)”.
In recent years, unmanned aerial vehicles (UAVs) have been used to shorten on-site work time and replace work in difficult-to-reach places. UAVs are used in a wide variety of fields, including aerial photography, air transportation, agriculture, and surveying. In the field of surveying, the Geospatial Information Authority of Japan has prepared a surveying manual. A case study on the topographic interpretation using a UAV (Sugawara et al., 2021).
In this study, we tried description of cracks in bedrock outcrops using a UAV. The observations from up above or oblique above can enable to obtain three-dimensional information including direction and length of cracks. On the other hand, it is necessary to understand the accuracy of crack data specifically when crack size is small. We created three-dimensional point cloud data by SfM (Structure from Motion) technology from aerial images taken using a UAV, and measured strike and dip from the point cloud data using free software. In this presentation, we will introduce the method to read strike and dip from the point cloud data and show the result of comparison between the values from the aerial images and those measured in the field.
This study was funded by the Ministry of Economy, Trade and Industry, Japan as part of its R&D supporting programs “Establishment of Technology for Comprehensive Evaluation of the Long-term Geosphere Stability on Geological Disposal Project of Radioactive Waste (Fiscal Years 2023) (Grant number: JPJ007597)”.