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Abstract

In order to be believable, virtual human characters must be able to
communicate in a human-like fashion realistically. This dissertation
contributes to improving and automating several aspects of virtual
conversations.
We have proposed techniques to add non-verbal speech-related facial
expressions to audiovisual speech, such as head nods for of emphasis.
During conversation, humans experience shades of emotions much more frequently
than the strong Ekmanian basic emotions. This prompted us to develop a method
that interpolates between facial expressions of emotions to create new ones
based on an emotion model.
In the area of facial modeling, we have presented a system to generate
plausible 3D face models from vague mental images. It makes use of a morphable
model of faces and exploits correlations among facial features.
The hands also play a major role in human communication. Since the basis for
every realistic animation of gestures must be a convincing model of the hand,
we devised a physics-based anatomical hand model, where a hybrid muscle model
drives the animations. The model was used to visualize complex hand movement
captured using multi-exposure photography.