“…We can mainly classify it into four categories: region-based approaches, which are based on the variation of image regions in motion (Khan et al, 2001); feature-based (Wren et al, 1997;Fieguth and Terzopoulos, 1997;Li et al, 2003), that usually utilize information about color, texture, etc. ; contour-based (Isard and Blake, 1996;Nguyen et al, 2002;Roh et al, 2007), that make use of the bounding contours to represent the target outline; and model-based methods (Gavrila and Davis, 1996;Andriluka et al, 2010) that explicitly require a 2D or 3D model of a person for tracking. However, a too detailed review of all the approaches is beyond the scope of our paper, therefore, in the following we will focus on people tracking-by-detection methodologies, more related to our work.…”