Image Resolution-Based Path Planning and Metrics for Exhaustive Area Search from Small UAVs

Abstract

Unmanned Air Vehicles (UAVs) are being retrofitted with a spectrum of sensors to allow rapid collection of data from an aerial perspective. Typical advanced surveillance techniques are best-served when onboard sensors yield as much unique information as possible with as little redundancy as possible. As an example, small UAVs are being tested for use as aerial video-gathering platforms within Wilderness Search and Rescue (WiSAR) efforts. UAVs can help accelerate the ground search WiSAR through returning quality aerial footage of the terrain. Additionally, numerically tracking the progress of a search by recording video resolution data potentially increases confidence that a comprehensive search of the region has been made. This paper presents methods for efficient area-search waypoint planning along with measurement tools for analyzing the quality of the search in terms of image resolution from a UAV-mounted wireless video camera system. When a UAV operator knows the size of the search target, intelligent choices can be made regarding the desired image resolution (driving camera lens selection and altitude), thus providing a metric to use when generating optimal search patterns. Several path generation methods are described and implemented in simulation. Flight-test results of aerial wide-area searches from UAVs demonstrate ways that these metrics can help ensure high quality video data is gathered for the WiSAR ground team.