Onboard Marker-Less Detection and Localization of Non-Cooperating Drones for Their Safe Interception by an Autonomous Aerial System

In this letter, a novel approach to fast three-dimensional (3-D) localization of flying objects for their interception by a micro aerial vehicle (MAV) is presented. The proposed method utilizes a depth image from a stereo camera to facilitate onboard detection of drones, flying in its proximity. The method does not rely on using any kind of markers, which enables localization of non-cooperating drones. This approach strongly relaxes the requirements on the drones to be detected, and the detection algorithm is computationally undemanding enough to process images online, onboard an MAV with limited computational resources. This allows using the detection system in the control feedback of an autonomous aerial intercepting system. Output of the detection algorithm is filtered by a 3-D multi-target tracking algorithm to reduce false positives, preserve temporal consistency of the detections, and to predict positions of the drones (e.g., to compensate camera and processing delays). We demonstrate the importance of the advances in flying object localization, presented in this letter, in an experiment with an intruder-interceptor scenario, which would be unfeasible using state-of-the-art detection and localization methods.