Computer vision, coupled with video projection using low cost devices, makes it possible for a human to use any convenient object, including fingers, as digital input devices. It is only used to verify the acoustic cues. To localize a person, colour and eye blink detection is applied.
Tracking is established using a correlation technique.
Vision for man-machine interaction. Vision for man-machine interaction. Maes, Darrel et al. 1994 Doc 9 Towards Automatic Evaluation of Multimodal User Interfaces - Balbo, Coutaz et al. The graph only includes citing articles where the year of publication is known.