Fig. 1

Schematic system overview. The mechanical custom structure represents the support for the five screens, the five speakers, the six SmartEye cameras running at 60 Hz and two IR-diodes used for illuminating the face of the subject in order to minimize the effect of varying environmental lighting conditions and for using the reflections of these IR flashes on the cornea (“glints”) to find the centre of the eyes. The stimuli management has been obtained using a laptop combined with the audio–video external devices. In the lower part of this overview, it is possible to observe the gaze heading frame of reference