Simplified Facial Animation Control Utilizing Novel Input Devices: A Comparative Study

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Summary:
This paper by Nikolaus Bee, Bernhard Falk and Elisabeth Andr´e from the University of Augsburg's Institute of Computer Science details new methods and controls for manipulating facial animations.  First, the researchers discuss the advantages and drawbacks of predominant current methods for facial animation control.   Slider-based GUI systems, for example, are easy to implement and familiar to users, but they afford control over only one parameter at a time and do not typically have an obvious mapping for manipulation.  The authors discuss several previous studies about direct-mapping including data gloves, data suits, and midi keyboards; they also detail typical facial expression generation technologies like the Facial Action Coding Systems (FACS) which has been used in everything from the Lord of the Rings Trilogy to Half-Life 2.  The researchers implemented FACS to drive the facial model - "Alfred" - that they used for their study.

Basically, control points on Alfred's facial structure were mapped to various buttons on an XBox 360 controller or data glove with three different settings - upper face, lower face without inner lips, and inner lips.

To evaluate the ease of use of this system, the authors recruited a group of 17 subjects who were trained in using the slider and gamepad systems and then asked to create three facial expressions based on a photo.  Overall, the participants found the gamepad more enjoyable, accurate, and satisfying to use than sliders.  The gamepad also created a nearly 30% increase in speed for most cases.


Discussion:
The authors' work in this area is very promising.  The obvious application for such a system would be for users to tweak the facial expression of their XBox Live avatar as they see fit.  It would also be cool if players could create simple animations for sending messages to friends or other players on the network.  Allowing gamers this level of customization to their characters might increase the affective level of interaction between players.