3D Reconstruction of Bird Flight Trajectories Using a Single Video Camera

Abstract

7Video cameras are finding increasing use in the study and analysis of bird flight over short 8 ranges. However, reconstruction of flight trajectories in three dimensions typically requires 9 the use of multiple cameras and elaborate calibration procedures. We present an alternative 10 approach that uses a single video camera and a simple calibration procedure for the 11 reconstruction of such trajectories. The technique combines prior knowledge of the bird's 12 wingspan with a camera calibration procedure that needs to be used only once in the system's 13 lifetime. The system delivers the exact 3D coordinates of the bird at the time of every full 14 wing extension, and uses interpolated height estimates to compute the 3D positions of the 15 bird in the video frames between successive wing extensions. The system is inexpensive, 16 compact and portable, and can be easily deployed in the laboratory as well as the field. 17 18 19 GPS-based tracking methods (e.g. Bouten et al., 2013) are useful for mapping long-range 43 flights of birds, for example, but are not feasible in indoor laboratory settings, where GPS 44 signals are typically unavailable or do not provide sufficiently accurate positioning. 45 Furthermore, they require the animal to carry a GPS receiver, which can affect the flight of a 46 small animal. 47

Lights, Camera, Mirrors, Action! Toolbox for 3D Reconstruction and Analysis Using a Single Camera and Planar Mirrors

“…However, this approach can only reconstruct static 3D objects. Srinivasan et al (2018) used a simple calibration pattern, along with a single camera, to estimate the 3D trajectory of the subject in controlled settings. This approach requires apriori information about the subject (wingspan) and can only estimate a single 3D point.…”