Relative position measurements in vision-based multi-person tracking

Vision-based multi-person tracking is the problem to estimate the positions of persons while simultaneously differentiating individual persons in a sequence of monocular images. For robustness and efficiency, it is crucial to measure positions of individual persons. Absolute position measurement is one of standard measurements, which provides the absolute position of a person with respect to the floor plane. However, absolute position measurement alone is often not reliable due to the inherent uncertainty in depth. In this paper, a novel type measurement, called relative position measurement, is introduced to determine the position relationship between two persons. Such a measurement provides useful information for differentiating individual persons. Moreover, an effective, tracking algorithm is proposed based on a particle filtering technique to combine the advantages of the absolute and the relative position measurements.