ABSTRACT
In recent years, research eff orts seeking to provide more natural, human-centered means of interacting with computers have gained growing interest, particularly in the context of universal access. A particularly important direction is that of perceptive user interfaces, where the computer is endowed with perceptive capabilities that allow it to acquire both implicit and explicit information about the user and the environment. Vision has the potential of carrying a wealth of information in a nonintrusive manner and at a low cost; therefore, it constitutes a very attractive sensing modality for developing perceptive user interfaces. Many approaches for vision-driven interactive user interfaces resort to technologies such as head tracking, face and facial expression recognition, eye tracking, and gesture recognition.
