1. Computer Vision and Aerial Robotics Group, Centre for Automation and Robotics (CAR), Universidad Politécnica de Madrid (UPM-CSIC), 28006 Madrid, Spain
2. Department of Electrical Engineering, University Carlos III of Madrid, 28919 Leganés, Spain
3. Drone-Hopper Company, 28919 Leganés, Spain
4. Department of Network, Faculty of Information Systems and Computer Science, October 6 University, Giza 12511, Egypt