A user wears the researchers' experimental setup — a Vive HMD augmented with SMI gaze tracking. Superimposed are the top view of the recorded movements of the physical path in a 3.5 m × 3.5 m real room and the virtual path in a much larger 6.4 m × 6.4 m synthetic space. The team showed saccades can significantly increase the rotation gains during redirection without introducing visual distortions or simulator sickness. Their new method can be applied to large, open virtual spaces and small physical environments for room-scale VR.
One of the major virtual reality (VR) challenges has now been overcome and it should greatly improve the user perception by enabling a more immersive experience while being physically limited to one's actual real-world space.
A computational framework that gives virtual reality users the perception of infinite walking in the virtual world, while limited to a small physical space ended up created by computer scientists from Stony Brook University, NVIDIA and Adobe.
The framework also enables this free-walking experience for users without causing dizziness, shakiness, or discomfort typically tied to physical movement in virtual reality. And, users avoid bumping into objects in the physical space while in the virtual reality world.
To do this, the researchers focused on manipulating a user's walking direction by working with a basic natural phenomenon of the human eye, called saccade.
Saccades are quick eye movements that occur when we look at a different point in our field of vision, like when scanning a room or viewing a painting. Saccades occur without our control and generally several times per second. During that time, our brains largely ignore visual input in a phenomenon known as "saccadic suppression"–leaving us completely oblivious to our temporary blindness, and the motion that our eyes performed.
Using a head- and eye-tracking VR headset, the researchers' new method detects saccadic suppression and redirects users during the resulting temporary blindness. When more redirection is required, researchers attempt to encourage saccades using a tailored version of subtle gaze direction — a method that can dynamically encourage saccades by creating points of contrast in our visual periphery.
To date, existing methods addressing infinite walking in VR have limited redirection capabilities or cause undesirable scene distortions; they have also been unable to avoid obstacles in the physical world, like desks and chairs. The team's new method dynamically redirects the user away from these objects. The method runs fast, so it can avoid moving objects as well, such as other people in the same room.
The researchers ran user studies and simulations to validate their new computational system, including having participants perform game-like search and retrieval tasks.
Overall, virtual camera rotation was unnoticeable to users during episodes of saccadic suppression; they could not tell they were being automatically redirected via camera manipulation. Additionally, in testing the team's method for dynamic path planning in real-time, users were able to walk without running into walls and furniture, or moving objects like fellow VR users.