Facial gesture interfaces for expression and communication

Considerable effort has been devoted to the automatic extraction of information about action of the face from image sequences. Within the context of human computer interaction (HCI) we may distinguish systems which allow expression from those which aim at recognition. Most of the work in facial action processing has been directed at automatically recognizing affect from facial actions. By contrast facial gesture interfaces, which respond to deliberate facial actions, have received comparatively little attention. This work reviews several projects on vision-based interfaces which rely on facial action for intentional HCI. Applications to several domains are introduced, including text entry, artistic and musical expression and assistive technology for motor impaired users.