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[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

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140 A. <strong>Babiarz</strong>, R. <strong>Bieda</strong>, and K. Jaskot<br />

hundr<strong>eds</strong> of fasc<strong>in</strong>at<strong>in</strong>g and challeng<strong>in</strong>g problems from the doma<strong>in</strong> of mechanics,<br />

electronics, automatic control and artificial <strong>in</strong>telligence that have to be solved and<br />

their solutions implemented. One of these problems is the task of build<strong>in</strong>g proper<br />

vision system, whose role and importance is briefly discussed <strong>in</strong> the next section.<br />

The general structure of the complete system for controll<strong>in</strong>g a group of mobile<br />

robots is presented on the Figure1. The system consists of play<strong>in</strong>g field (1.5x1.3<br />

m), camera (mounted about 2 m above the play<strong>in</strong>g field), vision system ( acquir<strong>in</strong>g<br />

images from the camera via frame-grabber card), controller1 which is actually<br />

an AI module, responsible for tak<strong>in</strong>g all decisions; and radio transmitter, which<br />

routes the control decisions made by the AI to the proper robots via radio l<strong>in</strong>k. The<br />

approach could be extended to multiple types of <strong>in</strong>formation and mobile robots<br />

[10].<br />

Fig. 1. Placement of vision system <strong>in</strong> the RoboSoccer control loop<br />

There are two teams with three mobile robots <strong>in</strong> each. Every robot is a cube<br />

hav<strong>in</strong>g dimension 7.5x7.5x7.5 cm. Teams play with orange golf ball. The robots<br />

have black walls and black top cover with colorful marker on it. The black is used<br />

because of the simplicity of algorithm remov<strong>in</strong>g unneeded parts of the scene dur<strong>in</strong>g<br />

vision process<strong>in</strong>g.<br />

From the control algorithm’s po<strong>in</strong>t of view, the vision system works as the<br />

feedback loop, provid<strong>in</strong>g measurements of values be<strong>in</strong>g <strong>in</strong>puts to the controller.<br />

Because the vision process<strong>in</strong>g is done on the on the host computer and not on<br />

board of a robot, it is possible to develop quite sophisticated and very precise vision<br />

algorithm, as the computational power of contemporary PCs is thousands as<br />

big as of micro-controllers used on-board the robots.<br />

<strong>Vision</strong> system could be also used for plann<strong>in</strong>g collision free path of other types<br />

of robots e.g. <strong>UAV</strong>s [7], [11]. Such problem is often solved with the methods of<br />

A.I [8].

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