Meta-path Analysis on Spatio-Temporal Graphs for Pedestrian Trajectory Prediction

Abstract

Spatio-temporal graphs (ST-graphs) have been used to model time series tasks such as traffic forecasting, human motion modeling, and action recognition. The high-level structure and corresponding features from ST-graphs have led to improved performance over traditional architectures. However, current methods tend to be limited by simple features, despite the rich information provided by the full graph structure, which leads to inefficiencies and suboptimal performance in downstream tasks. We propose the use of features derived from meta-paths, walks across different types of edges, in ST-graphs to improve the performance of Structural Recurrent Neural Network. In this paper, we present the Meta-path Enhanced Structural Recurrent Neural Network (MESRNN), a generic framework that can be applied to any spatio-temporal task in a simple and scalable manner. We employ MESRNN for pedestrian trajectory prediction, utilizing these meta-path based features to capture the relationships between the trajectories of pedestrians at different points in time and space. We compare our MESRNN against state-of-the-art ST-graph methods on standard datasets to show the performance boost provided by meta-path information. The proposed model consistently outperforms the baselines in trajectory prediction over long time horizons by over 32%, and produces more socially compliant trajectories in dense crowds.

Video

Meta-path Enhanced Structural-RNN

Our MESRNN model can be applied on any problem that can be represented as a Spatio-Temporal Graph. For example, the pedestrian trajectory prediction task can be represented as follows:

The task can be represented as a graph as shown below. Where red edges represent spatial edges and blue edges represent temporal edges. Edges represented as dashed lines are ones that are yet to be predicted while those represented by solid lines are edges which have already been observed or predicted.

We build a factor graph representation of this graph by including factors derived from meta-paths. 

Every edge and meta-path factor in the factor graph is represented using an EdgeRNN and every node factor in the factor graph is represented using a NodeRNN. All the EdgeRNNs and the NodeRNN are combined to form MESRNN. Their architectures are shown below:

EdgeRNN

NodeRNN

MESRNN

Qualitative Results

Here are a couple of example scenes showing the trajectories predicted by MESRNN and the baselines.

Citation

@inproceedings{hasan2022metapath,

  title={Meta-path Analysis on Spatio-Temporal Graphs for Pedestrian Trajectory Prediction},

  author={Hasan, Aamir and Sriram, Pranav and Driggs-Campbell, Katherine},

  booktitle={IEEE International Conference on Robotics and Automation (ICRA)},

  year={2022}

}