PNNL

Abstract

We present a new, efficient method for extracting three-dimensional animal motion trajectories from thermal stereo video data. Understanding animal behavior in the wild or other unconstrained environments is often based on animal movements. Capturing motion in three-dimensional space is important for flying animals like birds, bats and insects. In previous work, we developed a method for generating two-dimensional images of animal motion using thermal video from a single camera. The motion track image is formed by combining a sequence of video frames into a single composite image that shows the entire trajectory. Here we demonstrate that the composite motion track images from a stereo pair of thermal cameras can be used directly to generate three- dimensional tracks in real time without the need for an explicit tracking algorithm. The method was evaluated using an unmanned aerial system equipped with GPS. The estimated positions were compared to the GPS data and the flight height estimates were within meters of the GPS-derived flight height 90% of the time. The range estimates were within the bounds of the achievable accuracy of the cameras and camera arrangement used. The results demonstrate the practical usefulness of the method for assessing collision risk to seabirds at proposed wind energy sites and for quantifying avoidance behavior.