1. Introduction to visual interfaces

The use of human vision is essential in virtual reality and in many other fields (multimedia, CAD...). The ideal, universal visual interface should have metrological characteristics corresponding to the capabilities of the human visual system, in order to make the best use of this sensory channel. Readers with little knowledge of human vision can (and should) read up on the problems raised by visual interfacing, which is more complex than it seems, as soon as you want to use a device other than a simple monoscopic screen. Human vision is an active sense, not a passive one: constantly and unconsciously, your eyes converge and accommodate on the area observed, rotate in their orbit with or without head movement, operate in saccades... to provide the brain's visual areas with millions of stimuli to process.