The Cartoon Animation Filter

1
The Cartoon Animation Filter

• Jue Wang
• Steven Drucker
• Maneesh Agrawala
• Michael Cohen

2
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

3
A very boring animation
4
x(t) x(t) x(t) -
x
x
x
time
5
An almost as boring animation
6
-LoG
7
Convolution with -LoG
Error in equation (2) x(t) x(t)
-LoG
x(t) x(t) x(t) -LoG
8
-LoG Parameters
s

• Amplitude user set
• Width (frequency) automatically set later

9
Image Sharpening
10
Image Sharpening
11
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

12
Squash and Stretch
x
LoGp(t) LoG(tDt)
Dt x p
13
Squash and Stretch
x
time

• Volume Preservation
• Inversely stretch/squash orthogonally to
  acceleration

14
Squash and Stretch
15
Spin

• Show spin

16
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

17
Livening Up Powerpoint
18
Livening Up Powerpoint
19
Enhancing Video Objects
20
Enhancing Video Objects
21
Enhancing Video Objects

• Need to maintain constraints
• Simplest approach
• Move figure in each frame vertically to keep
  feet/skateboard in place

22
Enhancing Video Objects
23
Enhancing Video Objects
24
Enhancing Video Objects
25
Enhancing Video Objects
26
Enhancing Video Objects
27
Golfswing

• Apply filter to each DOF independently
• What should the filter width be?

28
Setting LoG Width
s(t) 2p / w(t)
w(t) maxw X(w) w
w(t) maxw F(x(t))
(over 32 frame window)
q
original
time
29
Walking
30
Boxers
31
Boxers
32
Boxers
33
Demo

• Realtime amplitude adjustment - mocap

34
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

35
Where from here?

• Make a kids animation system