A Tube-and-Droplet-Based Approach for Representing and Analyzing Motion Trajectories

作者:Lin, Weiyao*; Zhou, Yang; Xu, Hongteng; Yan, Junchi; Xu, Mingliang; Wu, Jianxin; Liu, Zicheng
来源:IEEE Transactions on Pattern Analysis and Machine Intelligence, 2017, 39(8): 1489-1503.
DOI:10.1109/TPAMI.2016.2608884

摘要

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.