Codebook-based background subtraction to generate photorealistic avatars in a walkthrough simulator

Abstract

Foregrounds extracted from the background, which are intended to be used as photorealistic avatars for simulators in a variety of virtual worlds, should satisfy the following four requirements: 1) real-time implementation, 2) memory minimization, 3) reduced noise, and 4) clean boundaries. Accordingly, the present paper proposes a codebook-based Markov Random Field (MRF) model for background subtraction that satisfies these requirements. In the proposed method, a codebook-based approach is used for real-time implementation and memory minimization, and an edge-preserving MRF model is used to eliminate noise and clarify boundaries. The MRF model requires probabilistic measurements to estimate the likelihood term, but the codebook-based approach does not use any probabilities to subtract the backgrounds. Therefore, the proposed method estimates the probabilities of each codeword in the codebook using an online mixture of Gaussians (MoG), and then MAP-MRF (MAP: Maximum A-Posteriori) approaches using a graph-cuts method are used to subtract the background. In experiments, the proposed method showed better performance than MoG-based and codebook-based methods on the Microsoft DataSet and was found to be suitable for generating photorealistic avatars. © 2009 Springer-Verlag.