Phrase structure detection in dance

This paper deals with phrase structure detection in contemporary western dance. Phrases are a sequence of movements that exist at a higher semantic abstraction than gestures. The problem is important since phrasal structure in dance, plays a key role in communicating meaning. We detect two fundamental dance structures - ABA and the Rondo, as they form the basis for more complex movement sequences. There are two key ideas in our work - (a) the use of a topological framework for deterministic structure detection and (b) novel phrasal distance metrics. The topological graph formulation succinctly captures the domain knowledge about the structure. We show how an objective function can be constructed given the topology. The minimization of this function yields the phrasal structure and phrase boundaries. The distance incorporates both movement and hierarchical body structure. The results are excellent with low median error of 7% (ABA) and 15% (Rondo).