Summary: Extraction and Analysis of Multiple
Periodic Motions in Video Sequences
Alexia Briassouli and Narendra Ahuja, Fellow, IEEE
Abstract--The analysis of periodic or repetitive motions is useful in many applications, such as the recognition and classification of
human and animal activities. Existing methods for the analysis of periodic motions first extract motion trajectories using spatial
information and then determine if they are periodic. These approaches are mostly based on feature matching or spatial correlation,
which are often infeasible, unreliable, or computationally demanding. In this paper, we present a new approach, based on the time-
frequency analysis of the video sequence as a whole. Multiple periodic trajectories are extracted and their periods are estimated
simultaneously. The objects that are moving in a periodic manner are extracted using the spatial domain information. Experiments with
synthetic and real sequences display the capabilities of this approach.
Index Terms--Periodic motion analysis, time-frequency distributions, short term Fourier transform.
PERIODICITY characterizes many movements, including
human and animal motions. For example, a beating
heart, flying birds, running and walking, all exhibit
periodicities. Also, the motions of wheels, windmills,
swings, and pendulums all have a periodic nature. The
characteristics of such motions play a fundamental role in
activity recognition and object tracking , .