A 3D Tube And Droplet Model Based Approach For Representing And Analyzing Motion Trajectories

Trajectory analysis is essential in many applications.In this paper,we address the problem of representing motion trajectories in a highly informative way,and consequently utilize it for analyzing trajectories.Our approach first leverages the complete information from given trajectories to construct a thermal transfer field which provides a context-rich way to describe the global motion pattern in a scene.Then,a 3D tube is derived which depicts an input trajectory by integrating its surrounding motion patterns contained in the thermal transfer field.The 3D tube effectively: 1)maintains the movement information of a trajectory,2)embeds the complete contextual motion pattern around a trajectory,3)visualizes information about a trajectory in a clear and unified way.We further introduce a droplet-based process.It derives a droplet vector from a 3D tube,so as to characterize the high-dimensional 3D tube information in a simple but effective way.Finally,we apply our tube-and-droplet representation to trajectory analysis applications including trajectory clustering,trajectory classification & abnormality detection,and 3D action recognition.Experimental comparisons with state-of-the-art algorithms demonstrate the effectiveness of our approach.