This paper presents a target tracking framework for unstructured
crowded scenes. Unstructured crowded scenes
are defined as those scenes where the motion of a crowd
appears to be random with different participants moving in
different directions over time. This means each spatial location
in such scenes supports more than one, or multi-modal,
crowd behavior. The case of tracking in structured crowded
scenes, where the crowd moves coherently in a common direction,
and the direction of motion does not vary over time,
was previously handled in [1]. In this work, we propose
to model various crowd behavior (or motion) modalities
at different locations of the scene by employing Correlated
Topic Model (CTM) of [16]. In our construction, words
correspond to low level quantized motion features and topics
correspond to crowd behaviors. It is then assumed that
motion at each location in an unstructured crowd scene is
generated by a set of behavior proportions, where behaviors
repr...