I. Introduction
Gesture recognition technologies are being widely applied to countless applications. One may notice a global tendency to replace traditional control devices with vision-based Natural Human Interaction (NHI) solutions. In a first step towards this goal, tactile interfaces are already in the market and allow the suppression of traditional input devices such as keypads and mouse. Indeed, the mid-term objective is to obtain marker-less, gesture recognition systems which allow users to interact as naturally as possible, providing a truly immersive experience.