Stanford's virtual reality headset reduces eye fatigue, nausea
04 August 2015
Stanford group's light-field stereoscope creates a dramatically more natural virtual reality experience than that of today's leading headsets.
Try any virtual reality headset and within a few minutes the sense of wonder might wear off and leave you with a headache or a feeling of nausea. Computational imaging experts say that's because current virtual reality headsets don't simulate natural 3D images.
Now, researchers from the Stanford Computational Imaging Group have created a prototype for a next-generation virtual reality headset that uses light-field technology to create a natural, comfortable 3D viewing experience. The device will be demonstrated at SIGGRAPH 2015 later this month.
In current 'flat' stereoscopic virtual reality headsets, each eye sees only one image. Depth of field is also limited, as the eye is forced to focus on only a single plane. According to Gordon Wetzstein, an assistant professor of electrical engineering at Stanford, in the real world we see slightly different perspectives of the same 3D scene at different positions of our eye's pupil. We also constantly focus on different depths.
When you look through a low-cost cardboard virtual reality headset or even a more expensive headset, there is a conflict between the visual cues your eyes focus on and how your brain combines what your two eyes see, called 'vergence'.
This mismatch is similar to that which causes motion sickness. If you read a book in a car, your eyes stay fixed on the text even when the car moves on a bumpy road. But, because your sense of gravity feels that bumpiness while you read, there is a mismatch between the cues of what you see and what you feel, thus creating the feeling of motion sickness.
The new light-field stereoscope technology – developed by Wetzstein along with researchers Fu-Chung Huang and Kevin Chen – solves that disconnect by creating a 'hologram' for each eye to make the experience more natural. A light field creates multiple, slightly different perspectives over different parts of the same pupil, with the result that the viewer can freely move their focus and experience depth in the virtual scene, just as in real life.
"You have a virtual window which ideally looks the same as the real world, whereas today you basically have a 2D screen in front of your eye," says Wetzstein.
The headset design incorporates two stacked, transparent LCD displays with a spacer. The researchers' prototype was made with off-the-shelf parts and is the first step toward a viable device.