Perceptive interfaces provide the computer with perceptive capabilities. Through perception, the machine becomes able to sense its environment, acquiring implicit and/or explicit information about users and what happens around them. Vision-based user interfaces, which receive data input through cameras, are an important part of this category.
We consider two kinds of interactions, which can be classified into two groups according to the active or passive role played by the user in the communication process. While in explicit communication users are fully aware that their actions will be interpreted as direct commands (e.g. hand or head gesture recognition), in implicit communication one's behavior is indirectly observed to draw information on what he/she is doing (e.g. phoning, talking to someone, etc.) or about emotional states (derived, for example, from the analysis of face expressions or eye activities). In general, our main goal is to develop and test interface systems in which computer vision technology is really useful, also (and above all) in everyday PC-based operations. One important field on which we are concentrating, however, is e-learning, where the use of natural forms of communication may make a big difference.
As our research is aimed at developing vision-based user interfaces and at exploring whether, when and how vision technology can be useful for PC-related tasks, we pay special attention to usability issues: of course, what we obtain must be really useful and usable.