AUTONOMOUS ROBOTS, vol.32, no.1, pp.15-34, 2012 (SCI-Expanded)
An attentive robot needs to exhibit a plethora of different visual behaviors including free viewing, detecting visual onsets, search, remaining fixated and tracking depending on the vision task at hand. The robot's associated camera movements-ranging from saccades to smooth pursuit-direct its optical axis in a manner that is dependent on the current visual behavior. This paper proposes a closed-loop dynamical systems approach to the generation of camera movements based on a family of artificial potential functions. Each movement from the current fixation point to the next is associated with an artificial potential function that encodes saliency and possibly inhibition depending on the visual behavior that the robot is engaged in. The novelty of this approach is that since the nature of resulting motion can vary from being saccadic to smooth pursuit, the full repertoire of visual behaviors all become possible within the same framework. The robot can switch its visual behavior simply by changing the parameters of the constructed artificial potential functions appropriately. Furthermore, automated reflexive changes among the different visual behaviors can be achieved via a simple switching automaton. Experimental results with APES robot serve to show the performance properties of a robot engaged in each different visual behavior.