The orientation of the long axis of the tracked object is also measured on-line. The principle of the system is to follow the object with a close-up image, keeping it near the centre of the image. The movements of the camera and details of the grabbed images allow the subsequent calculation of the bees' trajectory. These images are passed on to a frame grabber card within the computer. Body axis oriantation and object position in the frame are determined, 3.
Position is used to compute the steering commands for the camera.
The data are stored immediately for later use. Trackit 3D uses two cameras to obtain 3-dimensional position data. The system is designed for maximum flexibility and can adapt to various experimental designs. In many experiments it would be desired to be able to vary the stimulus conditions as a function of the animal's behaviour. In this way the stimulus conditions can be controlled and altered during the process of the trial.