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When will VR Become Indistinguishable from Reality?

Mark Metry, Founder of VU Dream
March 24, 2017
I bet the thought of TRUE VR has creeped in your mind at least once or twice. I’m defining “TRUE VR” as a virtual world that is indistinguishable from reality.
 
I get asked this question so often. At events, conferences, online on forums, websites etc.
 
Why is that?
 
EVERYONE THINKS ABOUT THIS. If you talk to someone who has no awareness of the current vr market or its existence. They would assume virtual reality is like reality but in a virtual space.
 
Has any of you seen Black Mirror? Most of you probably have. It’s a great show I highly recommend it.
 
Black Mirror
 
In “San Junipero” people are able to enter virtual reality and experience the world as if they were actually there. The system factors every thing you can think of, smell, senses, feelings etc.
 
Today we are going to be talking about the optical implications of a virtual reality system. An advanced VR system that is indistinguishable from reality.

Where the Progress is at Now.

It can be hard to keep up with all the virtual reality news. Seems like every day a new technological breakthrough is discovered. (Which is a good thing!)

 

12k VR Now Possible on Wi-Fi or LTE

This is especially great considering it’s on mobile and compatible with today’s hardware.
Tech Breakthrough 12k VR Now Possible over Wi-Fi or LTE
 

Liquid Crystal invented Triples the sharpness of Screens

Scientists have invented a new type of liquid crystal that allows tv and computer manufacturers to pack three times as many pixels into the same area of screen, while reducing the amount of power required to run the device.

This new type of blue-phase liquid crystal is so effective because it bypasses the colour filters used in current screen technology. This change alone reduces the amount of energy lost during light transmission by more than 40 percent.

 

Liquid Crystal

HTC Vive, Oculus Rift, and Playstation VR 

Check out this awesome comparison chart between the virtual reality systems.

Oculus vs HTC vs PSVR

Where do we need to go?

I have gathered research from two experts that are actively involved in the industry.
 
1. Kynan Eng – CEO at iniLabs neuroscience of VR and applications to rehabilitation
 
2. Changyin Zhou, Visbit.co cofounder; former GoogleX engineer.
 
 

1. Kynan Eng 

Kynan Eng

A future VR device with output visually indistinguishable from reality would feature:

  • 80 Mpixels per eye

  • Full human eye field of view: 170° horizontal x 130° vertical

  • 60x the current most powerful available consumer graphics card (Nvidia GTX 1080) for rendering synthetic game environments at 120 Hz – if you don’t render humans. If you want to render humans, increase that graphics power by a factor of at least 10.

(Calculations below current as of August 2016)
For comparison, one 8K display is about 35 megapixels.
 
Resolution & Field of View
 
For someone with 20/20 vision, the resolving power of their eyes is defined as 1 minute of arc, i.e. 1/60 degree. This means that for the pixels to be barely visible, a 360° display needs at least 360 * 60 = 21600 pixels of horizontal resolution.
 
The number of pixels actually needed in a VR display depends on the field of view. For example, the HTC Vive field of view is about 100° horizontal and 110° vertical. This means that for each eye it would need a display resolution of 21600 * 100/360 = 6000 pixels horizontal, and 6600 pixels vertical. This is about 40 megapixels of resolution.
 
The field of view of one Human eye is approximately 170° horizontal and 130° vertical. (We have a higher overall field of view due to partial overlap of our left and right visual fields – the stereoscopic vision area.) At full resolution, this works out to 10200 x 7800 pixels, or just under 80 MP for each eye.
 
The story is actually more complicated than the above calculations, for at least the following reasons:
 
  • Human acuity is non-uniform: the fovea has maximum resolution, while resolution drops off towards the periphery. So if you can track where the eye is looking fast enough, you don’t need to render all pixels at maximum detail.

  • Various visual acuity experiments have shown that the brain can do super-resolution in a training paradigm, i.e. results better than what is predicted by 20/20 vision. However, these cases are fairly artificial.

FOV

 
Graphics Rendering Hardware
 
The current most powerful consumer graphics card is the Nvidia GTX 1080. It can run several modern graphics-intensive games such as Far Cry Primal at 4K resolution at around 40 Hz. We will take the visual realism of these games as our current benchmark for reality – which is reasonably true for fairly static scenes if you ignore humans or other complex dynamic objects such as deformable fabric.
 
For our headset, we need 120 Hz over two eyes, as 120 Hz is the benchmark for VR. This means we will need a theoretical graphics card with 15x the power of the GTX 1080 – per eye – to hit the required performance for a display with the field of view of the HTC Vive. For a full-human-FOV display, this number increases to 30x GTX 1080 per eye.
Changyin Zhou Visbit
 
The answer is in the specs of human eyes:
Eye resolution
  • 60 pixels per degree in the center of view, and drop exponentially to the corner.

  • Either >12K x 12K resolution for VR device, or

  • Foveate display + precise eye tracking

 

Field of view

  • >180 degree if two eyes combined.
  • Experiments show that ~120 degree is about enough to be immersive. But 180 degree is obviously ideal.

Frame Rate

  • ~12 Hz. Yes, human eyes are super slow.

  • This is one of the most trick parts, long story and I will not elaborate here. Oculus suggests 90Hz now, and some Theory shows 200Hz is better.

 

Dynamic range

  • Eyes have about ~12 stops momentarily, and can adapt to a huge range of brightness if given time.
  • HDR display is a must (like 12 stops or higher)

 

Lens design

  • Human eye is very sensitive to aberration, which causes nausea.
  • Aberration: The lens should have very little aberrations, which means a lot more complicated lens design.

  • Diffraction: when display resolution gets close to 12K, we may reach the limit of diffraction. Good aperture and lens design will be needed. This will be a hard problem.

  • Eye box: each people have different eyes (size, ipd, etc). A large eye box is required to accommodate different eyes.

 

Eye

Focus

  • Human eye can focus to different distances in a fraction of second, which involves each eye’s focus and two eyes’ convergence.
  • When focus and convergence is not aligned for a long time, some people feel nausea — referred to as “Vergence-Accommodation Conflict”

  • The answer might resident in light field display, or wave optics, or fast eye-focus tracking.

  • This is probably the hardest problem.

Conclusion

Check back on this page frequently for updates and additions.

We’ve seen a tremendous amount of disruptive change coming from the Virtual Reality Industry. It is surely certain that this kind of content will accelerate based on trends in the future.

You most likely have some other VR ideas that can change the world! Share them with us on social media!

Thank you for Reading

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