Estimating the simulator sickness in immersive virtual reality with optical flow analysis

Recently, Virtual Reality (VR) has shown the ability of providing immersive experience to users and taking them to travel around the virtual environment. Sometimes when traveling in a large-scale virtual environment, the tracking space may not be large enough to fit the virtual environment. Several moving approaches such as virtual jumping and flying are proposed to overcome this limitation. Nevertheless, inappropriate design of moving approaches will cause serious simulator sickness. Intensive visual flow can be one of the major factors that cause the simulator sickness. According to Oculus Best Practices [Oculus 2017], it is necessary to avoid an intensive display of visual flow while developing VR application. There are several researches trying to combat simulator sickness through reducing optical flow. FOV restrictor [Fernandes and Feiner 2016] is one of the successful ways. By decreasing the FOV of the HMD, it can effectively reduce optical flow from peripheral vision and make users feel more comfortable. However, the immersiveness in VR will be declined due to the limited size of FOV.