Y.Liu, R.Collins and Y.Tsin,
"Gait Sequence Analysis using Frieze Patterns,"
European Conference on Computer Vision,
Copenhagen, May 2002, pp.657-671. Also,
Technical Report CMU-RI-TR-01-38, Robotics Institute,
Carnegie Mellon University, December, 2001.
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.
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