1) Firstly we convert the raw depth image frame into the depth float image frame, assume the depth float image is ' ( ) i D p ∈ℜ at time i and that every pixel is p (x, y)Τ = in the image domain p∈ϑ ∈ℜ , and then smooth the depth float image for de-noising adopting a bilateral filtering[8]. It is a simple, non-iterative scheme for edge preserving smoothing. With the purpose of getting a better filtering effect, bilateral filtering combines domain and range filtering. In this paper, we use the bilateral filtering in the case of Gaussian which can be described as follow: