the cartoon animation filter jue wang steven drucker maneesh agrawala michael cohen
Post on 20-Dec-2015
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The Cartoon Animation Filter
Jue WangSteven Drucker
Maneesh AgrawalaMichael Cohen
The Cartoon Animation Filter
• Goal– Add “liveliness” to any motion signal
• Should be– Simple– General– As automated as possible– Fast enough for real-time interaction
A very boring animation
x*(t) = x(t) + x’’(t) * -x’
time
x
x’’x’’
-x’’
-x’’ + x
-x’’ , x
Anticipation
Follow-through
An almost as boring animation
x*(t) = x(t) + x’’(t) * -x*(t) = x(t) + x (t) * - ’’
-LoG
Convolution with -LoG
Error in equation (2):
x*(t) = x(t) * -LoGx*(t) = x(t) + x(t) * -LoG
-LoG Parameters
• Amplitude – user set
• Width (frequency) – automatically set [later]
Image Sharpening
Image Sharpening
Demo 3
• Show ball with vectors forward and backward
• Show 3 copies of curve, original and time shifted forward and back
• Convolve
• Show squash and stretch ball again
Squash and Stretch
x’’
LoGp(t) = LoG(t+t)
t ≈ x’’ · p
p
Squash and Stretch
time
x’’
• Volume Preservation– Inversely stretch/squash orthogonally to acceleration
Squash and Stretch
Related Work
• Physically Based, lots
• Stylized, e.g., Chenney et al. 2005, Igarashi et al. 2002
• Surface Deformation, lots…
• Signal Based, e.g., – Unuma et al. 1995, – Bruderlin and Williams, 1995
• Video Paintbox, Collomosse 2004
• Motion Magnification, Liu et al. 2005
Livening Up Powerpoint
Livening Up Powerpoint
Enhancing Video Objects
Enhancing Video Objects
Enhancing Video Objects
• Need to maintain constraints– Simplest approach– Move figure in each frame vertically to keep
feet/skateboard in place
Enhancing Video Objects
Enhancing Video Objects
Enhancing Video Objects
Enhancing Video Objects
Enhancing Video Objects
Golfswing
• Apply filter to each DOF independently
• What should the filter width be?
Setting LoG Width*(t) = max|X()| *(t) = max|F(x’(t))| (t) = 2/ *(t)
time
original
fixed
adaptive
(over 32 frame window)
Walking
Boxers
Boxers
Boxers
Discussion
• (Almost) fully automated– NOT a tool for experts– But may make good first cut
• Need better constraint maintenance– IK, physical constraints
• Online (in-game) usage– Single animation adjusts to situation
Where from here?
• Make a kid’s animation system