Attention-driven eye gaze and blinking for virtual humans
Proceedings of the SIGGRAPH 2003 conference on Sketches & applications in conjunction with the 30th annual conference on Computer graphics and interactive techniques - GRAPH '03
Gaze and blinking have recently been considered for application to social interactions among computer characters based on emotional states. In this sketch, we present improvements to a gaze controller in terms of both the contributions by the joints involved in the motion and also by a closer analysis of the role of blinking and blink synchronisation in the realism of the final animation. Unlike previous approaches, our controllers are driven by internal character states derived from, among
... ved from, among other factors, a model of visual attention and short-term memory. Given a position to look at and taking into account internal state information such as an agent's interests, motivation and memory, the gaze and blink controllers are charged with the responsibility of executing an appropriate gaze motion in an expressive manner. We have previously presented a system [Peters and O' Sullivan 2003], based on research from the field of cognitive engineering [Itti et al. 1998], for the automatic generation of bottom-up visual attention behaviours in virtual humans. The system processes an input image from a synthetic vision module, calculating local contrast for intensity, orientation and colour features and then combining the results into a single saliency map using a normalisation procedure. The output of the attention system is passed to a gaze controller, in order to generate a realistic gaze motion towards the current most salient location. Gaze motions are parameterised in terms of the contribution of the eye, head, neck and shoulder joints to the movement and the total dwell time spent on the target before moving to the next target. Based on evidence from psychology [Bard et al. 1991], virtual humans are tagged with a head-move attribute, defining how likely they are to turn their heads to look at objects. Although subtle, we regard blinking motions as being highly important for conveying realistic gaze motions. Our primary focus is on the relationship between blinking and gaze shifts, referred to as gaze-evoked blinks in the psychology literature [Evinger et al. 1994]. These blinks typically begin simultaneously with the initiation of the head/eye movement and the probability of a blink increases with the size of the gaze shift. Furthermore, the amplitude of the gaze motion has been shown to affect the magnitude of the blink. These features have been incorporated into our gaze control system; when a gaze shift is imminent, a blink procedure is invoked and initialises a blink animation with the desired blink magnitude for the corresponding eccentricity.