Micro-unmanned aerial vehicle-based volcano observation system for debris flow evacuation warning. - Keiji Nagatani; Seiga Kiribayashi; Ryosuke Yajima; Yasushi Hada; Tomoaki Izu; Akira Zeniya; Hiromichi Kanai; Hiroyuki Kanasaki; Jun Minagawa; Yuji Moriyama (J. Field Robotics, 2018)