Recognizing conversation groups in an open space by estimating placement of lower bodies

This article discusses the problem of recognizing groups of people in conversation with each other in an open space. Previous work on this problem takes an approach based on the knowledge that people in the same conversation group often makes a circular formation called an F-formation, by referring to the work in social psychology. Since the F-formation describes spatial and orientational characteristics of the lower bodies of people, their positions and orientations need to be obtained for employing the approach. However, it is difficult to observe lower bodies by cameras, especially for people in a circular formation, due to occlusions between their bodies. We propose to recognize conversation groups while estimating the positions and orientations of the lower bodies of the people only from the information of their head positions and facial orientations observable from a single camera, by considering that the lower bodies of the people are arranged in a circular pattern if they are in the same conversation group.