UAV-based remote sensing for vegetation cover estimation using NDVI imagery and level sets method

摘要

Vegetation is a key component of nearly all global ecosystems, having a role of regulating various biogeochemical cycles in nature, as well as maintaining the energy balance at the earth's surface and atmospheric boundary layer. Therefore, it is of wide importance to constantly monitor the changes in vegetation cover and structure, especially those that are due to human influence. Backed up by many global initiatives for vegetation preservation and monitoring, it is necessary to have a system to collect and analyse different vegetation indices and products. One of the most important parameters of calculating many of these indices, is the amount of the vegetation cover in a certain area. This paper proposes a compact system for estimating vegetation in a certain area. The proposed system consists of a small UAV platform with the ability of performing autonomous flights and recording the videos of the ground cover using a camera with a modified infrared filter lens for obtaining the composite NDVI videos. The video is analysed and processed to extract the most significant frames that form a mosaic representing the area recorded by the camera. Finally, a contour is calculated forming the boundary around the area on the mosaic image that contains pixels that represent vegetation or photosynthetic activity. The contour and the area inside the boundary can be used for segmentation and estimation of other vegetation indices.