Multi-plane Visual Odometry for Unmanned Aerial Vehicle Using a Thermal Camera

In this paper, a multi-plane infrared visual odometry (VO) algorithm is proposed for the navigation system of unmanned aerial vehicles (UAV) flying at a medium height for both day and night. It uses a monocular downward-looking and stabilized thermal camera, aided by a single laser beam to restore scale factor. The scale recovery is further improved by a series of comprehensive logics of taking different measurements into a multi-plane homography decomposition process, which makes the algorithm practicable and robust for the platform flying over various complex terrains with multiple planar surfaces. With the help of some sophisticated techniques, like keyframe replacement and subregion adaptive KLT tracker, the performance of motion estimation is further improved. This visual odometry algorithm allows UAV platforms to take various missions from a medium altitude when GPS is not available and illumination condition is poor.