Vision-based Perceptive Interfaces
Although the WIMP interaction paradigm (based on Windows, Icons, Menus and Pointing devices) has been very useful for providing a common face to computing, defining "universal" communication modalities for almost any type of application, new interaction options are now possible in the direction of "naturalness". Perceptual abilities that until few years ago were a prerogative of interpersonal communication can now be incorporated into interfaces able to acquire information about users and their surrounding environment.
Vision is certainly one of the most important perceptual channels for our lives, and could be very usefully applied to user interfaces. The field of Vision-Based Interfaces (VBI) is currently one of the most active, with great interest by several computer companies.
We consider the two main types of interaction identifiable for VBIs (depending on the active or passive role played by the user), namely "explicit" and "implicit" communication. While in explicit communication users are fully aware that their actions (e.g. gestures) will be interpreted in a certain way by the computer, in implicit communication users are indirectly "observed" to obtain information on what they are doing or what is happening in the nearby environment or, also, to get information about their "emotional states" through the recognition of facial features and body movements, or through the observation of proper ocular parameters (Eye Tracking).