I. Introduction
Hand gesture recognition is one obvious strategy to build user-friendly interfaces between machines and users. In the near future, hand posture recognition technology would allow for the operation of complex machines and smart devices through only series of hand postures, finger and hand movements, eliminating the need for physical contact between man and machine. Hand gesture recognition on images from common single camera is a difficult problem because occlusions, variations of posture appearance, differences in hand anatomy, etc. Despite these difficulties, several approaches to gesture recognition on color images has been proposed during the last decade [1] .