A 3D coverage path planning approach for flying cameras in nature environment under photogrammetric constraints

Coverage path planning is the operation of finding a path that covers all the points of a specific area. Thanks to the recent advances of hardware technology, Unmanned Aerial Vehicles (UAVs) have multiple use at present besides obvious military applications, such as nature environment 3D reconstruction. However most of the research focus on finding the coverage path in an planar coverage surface, without considering the photogrammetric constraints, such as constant distance for consistency resolution and normal orientation for orthophotograph. This paper present a modified back-and-forth 3D coverage path planning method for quadrotor with gimbal camera under photogrammetric constraints that can reduce the consumption of time and energy. First, the 3D terrain is modeled by quasi uniform B-spline surface for a mesh representation. Then, the center of the camera footprint on the terrain surface and the air points can be generated by photogrammetric constraints. Finally, a modified back-and-forth coverage path planning method has been used to calculate the scan direction and coverage path. The experiment results have showed that our method can cover all the waypoints in the air that satisfy all the photogrammetric constraints.