[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

78 Z. Kuś and A. Nawrat
of view. This paper examines the third case exclusively. In this case it is not possible
to use image processing methods [14] – [23] because of disappearing object
from the picture.
It is assumed that the camera is mounted under a helicopter whereas the tracked
object moves on the ground. It must be also assumed that the object moves on the
flat surface. In the abovementioned case a rapid gust of wind may result in losing
the object from the picture streamed via communication system [33]. The helicopter
position determines which part of ground is being observed. Thus the first
stage of control algorithm is the return of the helicopter to the horizontal position.
Next, the camera is set by the developed control algorithm to the direction defined
by the last object position. For the lucidity of the work the author concentrates
only on 2D space.
2 Camera Movements Correction
Main elements of the algorithm are based on the basic geometrical relationships
between the helicopter, camera and tracked object positions. The current object
position is calculated only in the moment when pattern recognition algorithms
give information that object is in the picture. This current object position is utilized
when the distortion causes camera turn in a completely different direction.
Figure 1 presents the assumed 2D scene.
The tracked object is on a flat surface and the camera is above it. It is assumed
that the helicopter flies in a position approximate to horizontal. The camera is
mounted at the bottom.
Fig. 1. The scheme of mounting a camera in a helicopter