Videography using a fast lock on, gimbal-mounted tracking camera to study animal communication

January 3 – Febuary 28, 2021

Meeting Abstract

S6-3  Tue Jan 5 11:00 – 11:30  Videography using a fast lock on, gimbal-mounted tracking camera to study animal communication Vo-Doan, TT; Straw, AD*; University of Freiburg; University of Freiburg

Video is a key data source for quantitative analysis of animal communication behaviors. Nevertheless, the limited spatial-temporal resolution of video makes it difficult to record images in which detailed pose information can be extracted while an animal moves over a large volume. The demands of high spatial and temporal resolution of the subject conflict with obtaining a large recording volume due to limited pixel counts and framerates of cameras. This problem is particularly pronounced in animals, such as flying insects, which travel rapidly over meters but whose body is orders of magnitude smaller. To address this issue, we have developed a fast lock on system which keeps a moving insect “locked” in the field of view of a high-resolution camera by continuously keeping the camera aimed at the insect as it moves. This is achieved by marking the animal with a small reflector which is illuminated and imaged with an additional optical system to the video camera. Both systems share the optical axis which can be aimed using a fast gimbal. This additional system consists of an illumination laser, focusing optics, and a quadrant photo diode. Electrical signals from the photo diode array are used to command the gimbal such that the image of the reflector is centered. By using electrical signal processing, the system is faster, cheaper and simpler than related solutions based on digital image processing, at the cost of decreased flexibility. Using this system, we have made lab-based videos of locusts and beetles in which legs and antennae remain in sharp focus even as the animal jumps and flies. We believe this technology will be useful in the study of animal communication, especially when combined with techniques such as automatic pose extraction from the recorded video.

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