Trajectory prediction and tracking using a multi-behaviour social particle filter

3D motion tracking is a challenging task when both the tracked object and the observer are moving. In this paper, we present a multi-behavioural social force-based particle filter to track a group of moving humans from a moving robot using a limited field-of-view monocular camera. The application is a robotic guide and while moving, the robot often loses visibility of one or more people in the group, who must still be tracked. As an example, due to limited space, when the robot takes a sharp turn to avoid an obstacle or circumvent a corner, the visibility of the people at the rear is lost for some time. Therefore, several human social behavioural aspects have been implemented to predict the human’s motion in a group. The model accounts for attraction and repulsion between the people of the group and those with the robot, to maintain a comfortable social distance with each other at equilibrium. Additionally, when any person leaves the group then the track is deleted and after joining the track is automatically re-initialized. In the literature, the time of invisibility is a criterion to detect a person who has left the system, which however cannot be used here since the invisibility may be due to a limited field of view or the robot making a sharp turn to avoid an obstacle or circumventing a corner. Social heuristics are used to accurately detect people leaving the robotic system. The tracked trajectory is compared with ground truth and our system gives a very less error when compared with several baseline approaches. False positives are reduced, and the accuracy also increased with our proposed model as compared to other baseline methods. This method has been tested on several scenarios to ensure its validity.