Gait Sequence Analysis using Frieze Patterns

Yanxi Liu, Robert Collins, and Yanghai Tsin
tech. report CMU-RI-TR-01-38, Robotics Institute, Carnegie Mellon University, December, 2001


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Abstract
We analyze walking people using a gait sequence representation that bypasses the need for frame-to-frame tracking of body parts. The gait representation maps a video sequence of silhouettes into a pair of two-dimensional spatio-temporal patterns that are periodic along the time axis. Mathematically, such patterns are called ``frieze'' patterns and associated symmetry groups ``frieze groups''. With the help of a walking humanoid avatar, we explore variation in gait frieze patterns with respect to viewing angle, and find that the frieze groups of the gait patterns and their canonical tiles enable us to estimate viewing direction. In addition, analysis of periodic patterns allows us to determine the dynamic time warping and affine scaling that aligns two gait sequences from similar viewpoints. We show how gait alignment can be used to perform human identification and model-based body part segmentation.

Keywords
gait analysis, frieze patterns, symmetry groups, AIC, model-based, moment-based, spatio-temporal analysis, gait alignment, frieze groups

Notes
Grant ID: NSF IIS-0099597
Associated Center(s) / Consortia: Vision and Autonomous Systems Center
Associated Lab(s) / Group(s): Human Identification at a Distance and Computational Symmetry
Associated Project(s): A Computational Model for Repeated Pattern Perception using Crystallographic Groups
Number of pages: 20

Text Reference
Yanxi Liu, Robert Collins, and Yanghai Tsin, "Gait Sequence Analysis using Frieze Patterns," tech. report CMU-RI-TR-01-38, Robotics Institute, Carnegie Mellon University, December, 2001

BibTeX Reference
@techreport{Liu_2001_3883,
   author = "Yanxi Liu and Robert Collins and Yanghai Tsin",
   title = "Gait Sequence Analysis using Frieze Patterns",
   booktitle = "CMU-RI technical report",
   institution = "Robotics Institute",
   month = "December",
   year = "2001",
   number= "CMU-RI-TR-01-38",
   address= "Pittsburgh, PA",
}