Master Thesis - Hochschule Bonn-Rhein-Sieg

5. Algorithms Master Thesis Björn Ostermann page 75 of 126
Figure 52: Fluctuation noise after the offset filter (12 cm) and plausibility filter
as shown in Figure 24
5.2.3 Adding a virtual robot base
As described in chapter 4.3.4 the base of the robot is not detected as an intrusion, because it can not be
removed during the background acquisition. Thus a virtual base has to be created. It is added to every
intrusion map after filtering, because otherwise the filter would remove it as noise.
Since the robot base is a near perfect circle the virtual base can be simulated by a circle. It is entered
by the user by its centre point and its radius (see chapter 4.3.4) in the GUI.
To be able to quickly add the base to the intrusion map in every loop, the virtual robot base is
computed from the user’s values after their entry and stored in a binary two dimensional array (see
Figure 53a). Since the base is to be a circle and the array a rectangle, each value in the array has to
indicate whether or not it is part of the base (inside or outside the circle).
a) b)
Inside camera‘s view
Outside
virtual
robot
base
Figure 53: a) Creating the virtual robot base, blue circle: robot base radius, blue cross: centre of robot
base, red square: not robot base, green square: robot base
b) Virtual base, added in the program (see Figure 26)