Using Track3D involves three steps: video recording, video tracking and analysis. But prior to the first recording, you need to calibrate the 3D space in which the animal is tracked.
Calibrate your test chamber
In this preparatory step, you instruct the program to determine the relationship between the animal's position in 3D and the projection on the 2D image coming from the video cameras. For this purpose, you a calibration frame is placed in the test chamber. For larger test chambers, you can also combine multiple calibration frames. Calibration is a one-time operation, provided that cameras and test chamber don't move relative to each other.
Using Track3D involves three steps
1. Video recording - Release the animal in the test chamber and record video as high-resolution digital video files, one for each camera. The two video recordings will be in perfect sync with each other. This way, the program can reconstruct the 3D position of the animal in each individual video frame. You can also run your tests in complete darkness by using infrared illumination.
2. Video tracking - Track the animal’s movement from the digital video files using the EthoVision XT software. The program records the two-dimensional coordinates of the moving animal in each individual video image. If desired, you can set EthoVision XT to track from a specific time point in the video.
3. Visualization and parameter calculation - Next, you use Track3D to convert the 2D coordinates from each camera view to one set of 3D coordinates. You can visualize the movement track in three dimensions, play back, rotate and zoom in and out for a better view. The program also calculates a large number of flight parameters such as distance moved, absolute and ground speed, and turn angles relative to the different planes.
Track3D has been developed in collaboration with the research groups of Prof. Willem Takken (Laboratory of Entomology) and Prof. Johan van Leeuwen (Experimental Zoology Group) of Wageningen University, The Netherlands.