On Motion Periodicity of Dynamic Textures

Dynamic textures (DTs) are videos of natural or artificial processes, such as waves, smoke, fire, or walking crowd. While activities and motion events produced by moving shapes are well localised in space and time, the spatiotemporal extent of most natural DTs is less definite. The notion of periodicity, or regularity, has been extensively studied in static texture analysis and in activity analysis, where it proved very useful. At the same time, much less attention has been paid to temporal (quasi-) periodicity of dynamic textures, despite the obvious fact that this property is inherent in dynamic texture. We discuss the reasons, then present a framework for quantitative motion periodicity analysis of DTs. Using the optic flow and adapting the SVD-based algorithm for signal period estimation [17], we measure degree of periodicity of natural dynamic textures. Numerous test results are presented, including the application of the temporal periodicity features to DT classification.