Integrating electrodes to headsets for human-system interaction and psycho-physiological monitoring

Research in human monitoring led to development of powerful tools for users-systems communication via recording electrophysiological data and sending them to the computer system. Eye and gaze tracking are standing as important methods for a broad range of human monitoring applications such as in neuroscience, psychology, industrial engineering, aeronautics, military, and medical expertise. Nowadays, the most used eye-tracking technique is video-based tracking based on infrared illumination. However, the tools using this technique present a certain number of disadvantages. Notably, for the head-mounted tools, such systems obstruct the visual field and therefore are not suitable for integration in real operational environments. An alternative technique is the electro-oculography (EOG) which consists in measuring the standing potential between the front and back of the eyes. This potential increases when the cornea approaches an electrode and it decreases when the cornea moves in the opposite direction. EOG represents one of the easiest methods to estimate eye movements by using low-cost low-energy consumption devices without obstructing the visual field nor handling infrared light. This technique is particularly convenient for the head-mounted peripherals such as audio or virtual reality headsets. Typical features of signal processing, such as the mean of fixation duration, saccadic rates, and blinks are explored in various environments including air traffic control, pilots and co-pilots of civil and military aircraft. Interestingly, the EOG, as well as electroencephalography (EEG) features were correlated to drivers’ and pilots’ workload, drowsiness and fatigue.