[Studies in Computational Intelligence 481] Artur Babiarz, Robert Bieda, Karol Jędrasiak, Aleksander Nawrat (auth.), Aleksander Nawrat, Zygmunt Kuś (eds.) - Vision Based Systemsfor UAV Applications (2013, Sprin

Object Tracking in a Picture during Rapid Camera Movements 81
flight. When there is distortion the object ceases to be visible in the picture. In the
case of distortion it may be stated that there is no object in the picture and considerable
changes of the object position or orientation appear. Then the helicopter
control system turns the helicopter to a nearly horizontal position. Afterwards
, , are measured. In the next step the correction angle is computed. The
helicopter must be turned at this angle. As figure 4 presents the position and orientation
of the camera are known. The position of the tracked object is known too.
This position was calculated before distortion. The angle is calculated on the
basis of camera and object positions. The angle is the angle of rotation which
compensates distortion.
Fig. 4. Terms of camera angles in relation to the tracked object
Required value of camera tilt angle is calculated on the basis of the object
and camera positions:
(2)
According to the terms in figure 4 it is obtained
(3)
It is necessary to account a sign of the angles. It depends on the object position in
relation to the camera position.