Characterizing Structured versus Unstructured Environments based on Pedestrians' and Vehicles' Motion Trajectories
This work addresses the need for quantitative environment classification to improve trajectory prediction algorithms for autonomous vehicles, but it is incremental as it builds on existing datasets and methods.
The paper tackled the problem of classifying pedestrian and vehicle trajectory datasets into structured versus unstructured environments by analyzing motion features like mean speed and trajectory variability, and found that features such as trajectory variability, stop fraction, and pedestrian density differ significantly between the two types, enabling dataset classification.
Trajectory behaviours of pedestrians and vehicles operating close to each other can be different in unstructured compared to structured environments. These differences in the motion behaviour are valuable to be considered in the trajectory prediction algorithm of an autonomous vehicle. However, the available datasets on pedestrians' and vehicles' trajectories that are commonly used as benchmarks for trajectory prediction have not been classified based on the nature of their environment. On the other hand, the definitions provided for unstructured and structured environments are rather qualitative and hard to be used for justifying the type of a given environment. In this paper, we have compared different existing datasets based on a couple of extracted trajectory features, such as mean speed and trajectory variability. Through K-means clustering and generalized linear models, we propose more quantitative measures for distinguishing the two different types of environments. Our results show that features such as trajectory variability, stop fraction and density of pedestrians are different among the two environmental types and can be used to classify the existing datasets.