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Emotions: The Art of Visual Communication for Virtual Agents. Emmanuel Tanguy Philip Willis Joanna J. Bryson University of Bath Department of Computer Science. Reseach funded by a studentship from the Department of Computer Science, University of Bath and the ESPRC grant GR/S/79299/01.
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Emotions: The Art of Visual Communication for Virtual Agents. Emmanuel Tanguy Philip Willis Joanna J. Bryson University of Bath Department of Computer Science Reseach funded by a studentship from the Department of Computer Science, University ofBath and the ESPRC grant GR/S/79299/01.
Virtual Actors: Text To Animation • In video games, films, educational software,… • Virtual Actor aims to communicate with humans • Democratise the creation of facial animation • Text to speech software + facial animation system • Emotionally Expressive Facial Animation System (EE-FAS) producing visual speech from tagged text
Marvin, the depressed robot • The Hitchhiker's Guide to the Galaxy: • Marvin: You can blame the Sirius Cybernetics Corporation for making androids with GPP... • Arthur: Um... what's GPP? • Marvin: Genuine People Personalities. I'm a personality prototype. You can tell, can't you...? <comm_func name="personal reaction" max_nb_fd="2" intensity="60"> You can blame Sirius Cybernetics Corporationfor making androids <comm_func name="Emphasizer" intensity="30" > with GPP... </comm_func> </comm_func> Marvin, depressed?
Levels of Control (LoC) What kind of facial representation can be added to the text? Levels of Control: • Static Graphical Representation (LoC1) • Graphical Deformation Commands (LoC2) • Facial Movements or Facial Signals (LoC3) • Facial Meanings (LoC4) • To be introduced in texts • It is more intuitive than other LoCs • To create visual speech
Facial Meanings • Two types of facial meaning: • Emotional (ex: Happy, Sad, etc) • Communicative (question mark, emphasise, etc) • A facial meaning has physical implementations, e.g. facial signals • 30 facial meanings and 50,000 facial signals (Terzopoulos and Waters, 1990). • One communicative function can have several facial signals. (Bavelas and Chovil, 2000; Pelachaud and Bilvi, 2003) • How to map a small number of facial meanings onto a large number of facial signals?
Emotional Context • We decided to use emotional contexts • Emotion models are widely used • In emotion models we distinguish two parts: • Emotion elicitation mechanisms and • Emotion representation • The Dynamic Emotion Representation (DER): • Why only the DER? • What for?
Dynamic Emotion Representation • Foundations of the DER: • Definitions of emotion types • Sloman model of mind processes • Picard’s description of • emotion impulses • emotion intensity
Dynamic Emotion Representation Configuration File Emotion Intensity Emotional Impulse
Emotional Expressions BM NM GM
Emotional Context for Animations • 1.30s: <comm_func name="personal reaction" intensity="60" > • 5.30s: <comm_func name=“emphasizer" intensity="30"> • 10.00s: <comm_func name="personal reaction" sec_emo_context="happiness" intensity="60" > • 13.20s: <comm_func name="question marker" intensity="60" > Context of happiness Context of sadness
Meanings of Facial Components • Purely categorical or componential approach? (Smith and Scott (1997)). • An experiment showing videos with individual facial movements: • Eyebrows frown; Lip corners raise; Eyebrows oblique • People’s perception measured on the following dimensions (60 subjects): • Happy; Angry; Sad; • Pleased/Displeased; Energetic/Lethargic; • Friendly/Unfriendly; Sincere/Insincere
Dimension Happy Lip corners raised involved in happiness expression Smith and Scott (1997)
Dimension Angry Frown involved in anger expression Smith and Scott (1997)
Dimensions Energy/Pleased From Russel, J. A. and J. M. Fernandez-Dols (1997). The Psychology of Facial Expression. Cambridge University Press.
EE-FAS Architecture • Modular • Customisable DER • Message passing mechanism • Implementation of all LoCs: • LoC1: 3D Mesh • LoC2: Abstract Muscles • LoC3: Facial Signals • LoC4: Emotions and Communicative functions • Customisable transformations from one LoC to another • Loose relation between LoCs
Conclusion (1) • We developed a Dynamic Emotion Representation (DER) model that enables users • To create their own Emotion Representation based on different emotion theories. • To represent any interacting variable, such as drives • We integrated an instance of the DER model within the EE-FAS • Technical Report on the DER: “A Dynamic Emotion Representation Model Within a Facial Animation System”, 2005, Emmanuel Tanguy, Joanna Bryson, Philip Willis, University of Bath
Conclusion (2) • Developed an Emotionally Expressive Facial Animation System (EE-FAS), which: • Enables non-specialist users to create facial animations • Is customisable through XML dictionaries • EE-FAS extends the number of facial expressions that a such system can produce by displaying: • Emotional expressions • Multiple facial signals for each communicative function • Fake or genuine facial expressions