For more than a decade, more number of human-machine interfaces had been developed by various combination of user inputs such as speech, hand and head gestures, eye gaze and body movements, etc. And many research issues have been addressed, including facial expression recognition, human emotion analysis, speech recognition/synthesis, human-computer interaction, virtual reality and augmented reality interaction, etc. As a result, the development of a hybrid approach becomes a central issue for hands-free high-level human computer, to help elderly and disabled people. They characterise the user's preferred communication style and support user's ability to flexibly combine modes or to switch from one input mode to another that may be better suited to a particular task or setting. This review discusses the various hybrid control approaches of hands-free high level human-computer interface.
Keywords: Hybrid control; electroencephalogram (EEG); electromyogram (EMG); eye blink; movements.