Rock slope monitoring using drone based multispectral and thermal images

Abstract

Nowadays, remote sensing compact sensors able to be attached to Unmanned Aerial Vehicle (UAV) platform, which suitable in monitoring and mapping the slope feature at large area. Therefore, this study presents the use of remote sensing compact sensors from visible spectrum (400 nm - 700 nm), Near-Infrared spectrum (700 nm - 1300 nm) and infrared thermography spectrum (1300 nm - 15000nm), respectively in order to produce an efficient technique for monitoring the stability of rock slope. Then, the stability of rock slope is being analyse using vegetation index such as Normalized Difference Vegetation Index (NDVI), water index with emphasizing to the Normalized Difference Water Index (NDWI) for different land type features and radiometry temperature extracted using thermography image. NDVI has been used in analysing the healthiness of vegetation and the healthier vegetation tends to have a stronger root which useful in stabilizing the slope. Meanwhile, the NDWI has the ability to detect the presence of water on the rock slope surface. In addition, the higher index of NDWI indicates the presence of water where at the higher index NDWI potentially be less stable as the water seeps through the crack line of the rock surface. For thermography, by acquiring the thermal data of the rock slope surface, it allows to analyze the damage due to weathering effect. As a summary, this technique is significant to be used as initial indicator to investigate the rock slope failure based on low cost technique and quick data information.