The simplest background model assumes that the intensity values of a pixel can be modeled by a single unimodal distribution. This basic model is used in .However, a single-mode model cannot handle multiple backgrounds, like waving trees. The generalized mixture of Gaussians (MOG) in has been used to model complex, non-static backgrounds. Methods employing MOG have been widelyincorpora ted into algorithms that utilize Bayesian frameworks , dense depth data, color and gradient information , mean-shift analysis, and region-based information .