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. The technology described here is for understanding how bird and bat behavior is affected by the presence of wind turbines, specifically offshore wind turbines which are challenging to monitor. There is a need for both baseline data prior to wind farm construction and post-construction data when the turbines are operating. Thermal cameras were chosen because they are equally effective both night and day. 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 flight 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 (UAS) equipped with GPS. The UAS flew both straight and curving trajectories at distances between 50 and 325 m from the camera system. The ThermalTracker-3D estimated positions were within ±10 m of the GPS-derived positions in the x and y (flight height) dimensions, and within ±20 m in the z (range) dimension for 90% of the data points.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 offshore wind energy sites and for quantifying avoidance behavior at operating offshore wind farms.

我们提出了一种从热立体视频数据中提取三维动物运动轨迹的有效方法。了解野外或其他不受约束的环境中的动物行为通常基于动物运动。此处描述的技术用于了解风力涡轮机（特别是难以监控的海上风力涡轮机）的存在如何影响禽鸟行为。在风力发电场建设之前，需要基准数据，而在涡轮机运行时，则需要建设后数据。选择热像仪是因为它们在白天和黑夜都同样有效。在以前的工作中，我们开发了一种使用来自单个摄像机的热视频生成动物运动的二维图像的方法。运动轨迹图像是通过将一系列视频帧组合成一个显示整个飞行轨迹的单个合成图像而形成的。在这里，我们证明了来自立体声热像仪对的合成运动轨迹图像可以直接用于实时生成三维轨迹，而无需明确的跟踪算法。使用配备GPS的无人机系统（UAS）对​​方法进行了评估。UAS在距摄像头系统50到325 m的距离内飞行了直线轨迹和弯曲轨迹。在90％的数据点上，ThermalTracker-3D估计的位置在x和y（飞行高度）维度上位于GPS衍生位置的±10 m内，在z（范围）维度内位于±20 m内。范围估计值在所用摄像机和所用摄像机布置可达到的精度范围内。结果表明，该方法可用于评估拟议海上风能站点对海鸟的碰撞风险以及量化海上海上风电场的避让行为。