A method for evaluating motion sickness induced by watchingstereoscopic images on a head-mounted display

摘要

It has been reported that even users of virtual environments and entertainment systems experience motion sickness. Thisvisually induced motion sickness (VIMS) is known to be caused by sensory conflict, for instance, the disagreementbetween vergence and visual accommodation while viewing stereoscopic images. The simulator sickness questionnaire isa well-known tool that is used herein for verifying the occurrence of VIMS. We used the SSQ and also quantitativelymeasured head acceleration and sway of the center of gravity of the human body before and during the exposure tostereoscopic images on a head-mounted display. During the measurement, the subjects were instructed to maintain theRomberg posture for the first 60 s and a wide stance (with the midlines of heels 20 cm apart) for the next 60 s. Weproposed a method to obtain stochastic differential equations (SDEs) as a mathematical model of the body sway on thebasis of the stabilogram. While there are several minimal points of time-averaged potential function in the SDEs, theexposure decreases the gradient of the potential function. We have succeeded in estimating the decrease in the gradientof the potential function by using an index called sparse density.