Visual-Inertial On-Board Throw-and-Go Initialization for Micro Air Vehicles

We propose an approach to the throw-and-go (TnG) problem for micro air vehicles (MAVs) using visual and inertial sensors. The key challenge is the fast on-board initialization of the visual odometry (VO) system, which usually requires user input to recover the visual scale. Our approach is based on the identification of the gravity vector from the acceleration data computed with images of the ground during in free fall. This enables scaling of the poses reconstructed with visual information. The proposed framework use inertial data to control the MAV attitude so the ground is visible after the throw. Using image to image homography a metric scale is estimated with which the MAV's height is propagated. Unlike existing literature, this approach requires no additional sensor nor user input or pre-throw assumptions and can recover from any initial attitude. We show results on both simulation and real data.