Motion Modeling for Online Locomotion
Synthesis
Taesoo Kwon and Sung Yong Shin
KAIST
Outline
• Motivation
• Related work
• Overview
• Motion analysis
• Motion synthesis
• Conclusions
• Future Work
Motivation
• Real-time locomotion synthesis
• Motion rearrangement : realism
• Motion blending : efficiency and controllability
• Hybrid approach– Locomotive motion generation [PSS02, PSS04]– Rhythmic motion synthesis [KPS03]
• Premise: motion labeling
Related Work
• Motion Segmentation [Bindiganavale & Badler, 1998;Fod et al., 2002;
Kim et al., 2003]
• Motion Classification [Arikan et al., 2003;Kovar & Gleicher, 2004;Forbes & Fiu
me 2005;Mueller & Roeder 2005]
• Motion Labeling for blending [Kim et al., 2003]
Overview
motion specifications
desiredmotion
example motions
motion analysis
hierarchical motion transition graph
motion synthesis
Motion Analysis
• Issues– Motion segmentation
– Motion classification
– Graph construction
• Biomechanical observations– [Per92,Win90]
Biomechanical Observations• Center of mass trajectory
right foot left foot
walk runtransition
COMy
Motion segmentation
• Criteria for motion segmentation– Simple enough for intuitive parameterization
– Long enough to contain motion semantics
– An important motion feature should not be split
Split at every COM peak
Motion Classification
• String encoding–
• Pros– avoid troublesome time-warping
– more robust than numerical computation
M:f
Motion Classification
• Footstep patterns
(a) S (b) R (c) L (d) D (e) F FDLRS , , , ,
Motion Classification
• String Encoding (ideal case)
Motion Classification
• String Encoding (ideal case)
R D L
Motion Classification
• String Encoding (ideal case)
F R F
Motion Classification
• String Encoding (ideal case)
R D L F
Motion Classification
• String Encoding (ideal case)
Refinement
• False peak– Concatenate two motion segments
• Missing peak– Divide a motion segment into two
Graph Construction
Graph Construction
mmmmmmP avftt ,,,,
Motion Analysis Results
• O(n) – 2Ghz PC (AMD 64, 2GB memory)
– For 7.4 min locomotion, about 10 seconds
• Movie
Motion Synthesis
LDR RDL LDRF… …
Motion Synthesis
• Motion specification
• Motion parameter
Motion Sythesis
• How to calculate – Two half cycles in cyclic motion
–
• Regression analysis on
m
RL mm
RL mm
Motion Synthesis
• Motion blending : [PSS04][KG03][ACP02]
• Motion stitching : [GSKJ03]
• Motion retargeting : [SLSG01][KGS02]
Motion Synthesis Result
• 1000+ frames per second
• Movie– Path following
– Online synthesis
Conclusion
• Motion labeling based on string encodings
• Hierarchical motion transition graph
Future work
• Footstep-driven motions such as dancing and boxing