Simulating Virtual Environments within Virtual Environments as the Basis for a Psychophysics of Presence

摘要

A new definition of immersion with respect to virtual environmentrn(VE) systems has been proposed in earlier work, based on the conceptrnof simulation. One system (A) is said to be more immersivernthan another (B) if A can be used to simulate an application asrnif it were running on B. Here we show how this concept can bernused as the basis for a psychophysics of presence in VEs, the sensationrnof being in the place depicted by the virtual environmentrndisplays (Place Illusion, PI), and also the illusion that events occurringrnin the virtual environment are real (Plausibility Illusion, Psi).rnThe new methodology involves matching experiments akin to thosernin color science. Twenty participants first experienced PI or Psi inrnthe initial highest level immersive system, and then in 5 differentrntrials chose transitions from lower to higher order systems and declaredrna match whenever they felt the same level of PI or Psi as theyrnhad in the initial system. In each transition they could change therntype of illumination model used, or the field-of-view, or the displayrntype (powerwall or HMD) or the extent of self-representation byrnan avatar. The results showed that the 10 participants instructed tornchoose transitions to attain a level of PI corresponding to that in therninitial system tended to first choose a wide field-of-view and headmountedrndisplay, and then ensure that they had a virtual body thatrnmoved as they did. The other 10 in the Psi group concentrated farrnmore on achieving a higher level of illumination realism, althoughrnhaving a virtual body representation was important for both groups.rnThis methodology is offered as a way forward in the evaluation ofrnthe responses of people to immersive virtual environments, a unifiedrntheory and methodology for psychophysical measurement.