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International Journal of Computer Games Technology
Volume 2008, Article ID 542918, 7 pages
Research Article

A Real-Time Facial Expression Recognition System for Online Games

School of Computer Science and Software Engineering, University of Wollongong, NSW 2522, Australia

Received 31 July 2007; Accepted 31 January 2008

Academic Editor: Kok Wai Wong

Copyright © 2008 Ce Zhan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Multiplayer online games (MOGs) have become increasingly popular because of the opportunity they provide for collaboration, communication, and interaction. However, compared with ordinary human communication, MOG still has several limitations, especially in communication using facial expressions. Although detailed facial animation has already been achieved in a number of MOGs, players have to use text commands to control the expressions of avatars. In this paper, we propose an automatic expression recognition system that can be integrated into an MOG to control the facial expressions of avatars. To meet the specific requirements of such a system, a number of algorithms are studied, improved, and extended. In particular, Viola and Jones face-detection method is extended to detect small-scale key facial components; and fixed facial landmarks are used to reduce the computational load with little performance degradation in the recognition accuracy.