“…These points are gathered either with a bayesian framework as in (Brostow and Cipolla, 2006) and (Li and Ai, 2007), or with the RANSAC algorithm (Rabaud and Belongie, 2006). Hybrid methods combine both approaches to segment the crowd, in order to make the system more robust as in (Sidla and Lypetskyy, 2006). In the case of traffic monitoring, Hu (Hu et al, 2006) (with the additional hypothesis that an entity cannot partially hide another one), gathers features (spatial ones or trajectories) with Kmeans algorithm.…”