Cursive A novel interaction technique for controlling expressive avatar gesture Francesca...
-
Upload
caroline-robertson -
Category
Documents
-
view
221 -
download
0
description
Transcript of Cursive A novel interaction technique for controlling expressive avatar gesture Francesca...
CursiveA novel interaction
technique for controlling expressive avatar gesture
Francesca Barrientos and John CannyUC Berkeley
UIST 12 November 2001 , Orlando Florida
Cursive 212 November 2001
Avatar worlds
• Verbal communication– Chat– Spoken
• Nonverbal communication– Mechanisms
• Change image• Play animation
– Gestures have continuous qualities
Cursive 312 November 2001
Current techniques• Specialized widgets
Vlnet expression panel1. Select2. Modulate3. Trigger• 3 step process
ComicChat EmotionWheel• Select and modulate• Hunt and click diverts attention
• Avatar agencyBodyChat
• Driven by chat text• Lacks direct control
Cursive 412 November 2001
Expressive and Controllable
• Want gesture to be expressive– Range of gestures– Vary quality of gesture
• Single step - modeless• Enable co-occuring verbal and nonverbal
communication• Solution: pen gesture input
Cursive 512 November 2001
Mapping pen to avatar gesture• Pen gesture carries symbolic and qualitative data• Human/avatar gesture can be symbolic and qualitative• Pen gesture simultaneously selects avatar gesture and
modulates multiple expressive qualities
Data Pen Avatar
Symbolic Letter of alphabet Gesture type
QualitativeSize Magnitude
Duration SpeedPressure Effort
Cursive 612 November 2001
Conceptual modelLibraryGenerated offline
InputUser writes letter in GUI
GenerationGesture selection and modulation
Animation Gesture performed
GUI library
Gesture generator
Avatar animator
w-s-r-
Cursive 712 November 2001
Example: modulating size
• Writing letter ‘s’ triggers animation
• Single gesture• Modulation along
single parameter• Writing size
mapped to gesture’s size
Cursive 812 November 2001
Extraction
Character recognizer
Feature extractor
w-s-r-
Speed .5Size .3
Inputs modulate gesture
Style parameters
Gesture Typew-s-r-
Type library
GUI
Cursive 912 November 2001
Modulation through multilinear interpolation
• Joint trajectory I– Rotation angles over time
• Gesture type β– Semantic category– Set of 2n prototypes - G– n style parameters– Prototypes represent
extremal trajectories• Gesture instance Iβ(u,v )
– Vector of joint trajectories – Multilinear interpolation on
type produces instance
Speed u
Size v
k
l
Gβ
Iβ(0,1)
Iβ(0,0)
Iβ(1,1)
Iβ(1,0)
Iβ(l,k)Iβ(0,k) Iβ(1,k)
Cursive 1012 November 2001
Speed parameter special case
• Interpolation along curves of different durations
• Time dilation step– Determine duration for
interpolated curve– Choose sample rate on
interpolated curve– Compress slower curve -
sample at proportionately slower rate
– Sample faster trajectory at proportionately faster rate
Angle θ
t
Cursive 1112 November 2001
ArchitectureGesture producer
Animator
Animationcommands
VRML
scriptGesturecommands-
w-
s-
r-
Cursive 1212 November 2001
Communication
• User logs into Vworld server
• Other visitors receive notification
• Other visitors request and download avatar copy
• Animator opens socket connection to producer
• Generator sends gesture commands via socket
Web server
VWorld server
Cursive communicates with any copies of user’s avatar user hostvisitor host
loginnotificationrequest avataropen socketsends commandsDownload avatar
Cursive 1312 November 2001
Summary
• Current techniques lack expressive control of avatar gesture
• Apply pen gesture to avatar gesture• Modulate recorded gestures using
multilinear interpolation• Augmented VRML avatars can drop into
multi-user virtual worlds
Cursive 1412 November 2001
Conclusion
• Expressive avatar gesture• Single action invokes and
modulates gesture• Multidimensional
modulation• Enables co-occuring
verbal and non-verbal communication
Pen gestures control Thank Erin.