Mitigating Visual Discomfort on Head Mounted Displays using Estimated Gaze Dependent Depth of Field
Virtual Reality (VR) applications on Head Mounted Displays (HMDs) are now more common and accessible for personal viewing than before with the introduction of consumer-level devices like the Oculus Rift. However, exposure to VR applications on HMDs results in significant discomfort for the majority of people, the severity of which can both increase or decrease after repeated exposures. This is disadvantageous for the development and adoption of VR, as a long adaptation period cannot be relied on for making Virtual Environments palatable. Symptoms of discomfort caused by the viewing of content on VR devices including HMDs are historically described as “Simulator Sickness” and include eye fatigue, headaches, nausea and sweating; symptoms very similar to those experienced by sufferers of motion sickness. We refer to the specific subset of Simulator Sickness Symptoms caused by visual stimuli as symptoms of “Visual Discomfort”. A conflict between accommodation and vergence depth cues on stereoscopic displays is known to be a significant cause of visual discomfort. This report describes a psychophysical evaluation used for judging the effectiveness of dynamic Depth of Field (DoF) blurring on reducing visual discomfort caused by initial exposure to stereoscopic content on HMDs. Our DoF implementation adjusts the focal region of stereoscopic content based on an estimation of users’ view vectors in real time and is realised in a commercial game engine. Participants report a significant reduction of visual discomfort using a simulator sickness questionnaire when DoF blurring is enabled. On average, a 34% reduction in our sickness measure is observed, indicating that dynamic DoF blurring is an effective rendering technique for reducing visual discomfort.