Virtual Reality and Oculus Rift

Visual Imaging in the Electronic Age

Donald P. GreenbergNovember 17, 2015

Lecture #24

Virtual Reality

• A term used to describe a computer generated

environment which can simulate the perception of

PRESENCE.

Virtual Reality

• A person immersed within this virtual world can

manipulate objects, interact with the environment,

and explore the virtual world in the same

perceptual way as one interacts with the physical

world.

Augmented Reality

Augmented reality is the interpretation of digital graphical information with

live video or the user’s physical environment in real time.

UNC

Human in the Loop

• Abstract Interpretation

• Viewing a Picture on Television

• Cinema Viewing

• Presence

Microsoft’s Hololens

Magic Leap

Virtual Reality

• Field of view and resolution

• Color and dynamic range

• Speed (Refresh and update rates)

• Bandwidth

Cross Section of Eye & Retina

Rods and Cones

Rods and Cones

Upper figure adapted from Cornsweet. Visual Perception © Academic Press, 1971.

Two rightmost figures from Graham, Vision and Visual Perception © Wiley, 1966.

vernier

5-7”

min. detectable

0.5”min. resolvable

30”

Snellen letters

30”

detection resolution localization

Measures of Acuity

Resolution of the Human Eye

Resolution of the Human Eye

• Humans can tell visual details at distances larger than 0.3 arc minutes

• The Field of View (FOV) of the human eye can be generously estimated as

120 by 90 degrees

Resolution of the Human Eye

• (120 degrees x 60 arcminutes / degree x 1 pixel / 0.3 arcminutes) x (90

degrees x 60 arcminutes / degree x 1 pixel / 0.3 arcminutes)

• 431,568,000 pixels; 432 MegaPixels. A 1080p display is 2.1 megapixels.

The Significance of Movement-Sensitive Cells

- David H. Hubbel. EYE, BRAIN, AND VISION, 1988 Scientific American Books, Inc. p. 80.

- David H. Hubbel. EYE, BRAIN, AND VISION, 1988 Scientific American Books, Inc. p. 80.

The Significance of Movement-Sensitive

Cells

Lytro Camera

Vergence- Accommodation Conflict

Vergence – Accommodation Conflict

Samsung AMOLED Displays

Standard LCD RGB Display PenTile Display

Virtual Reality

• Field of view and resolution

• Color and dynamic range

• Speed (Refresh and update rates)

• Bandwidth

Refresh vs. Update Rate

• The “refresh rate” is the number of times per second the entire

image is drawn

• The “update rate” is the number of times per second the image is

changed

Refresh Rates

• Note that an insufficient refresh rate will cause “flicker.”

• For most cases the displays must be refreshed at least 50 cycles/second.

• Current virtual reality displays (2015) operate at 90 Hz.

Update Rates

• The human eye can process approximately 10-12 separate images per

second. To simulate motion, update rates must be greater than this.

• The movie industry has historically used 24 fps and the television

industry 30 fps.

• Recently, James Cameron (Avatar) and Peter Jackson (The Hobbit) have

been filming at 48 fps.

• Since in VR/AR continuous motion is paramount, then rendering must be

in (1000/24), about 40 milliseconds or less.

Cones interconnect in the retina, eventually leading to

opponent-type signals.Roy S. Berns. “Billmeyer and Saltzman’s Principles of Color Technology, 3rd Ed. 2000, John Wiley & Sons, Inc. p. 16.

Color-Receptive Fields

Channel Combination Resolution

black - white M + L very high

Green - red M – L High

yellow - blue M + L – S low

Full Color Image

YIQ http://en.wikipedia.org/wiki/YIQ

Luminance Image (Y)

YIQ http://en.wikipedia.org/wiki/YIQ

Color Addition (Red/Green Axis)(I)

YIQ http://en.wikipedia.org/wiki/YIQ

Color Addition (Yellow/Blue Axis)(Q)

YIQ http://en.wikipedia.org/wiki/YIQ

Research on Foveated Displays

Truck Art

DORSEY 1993

DORSEY 1993

DORSEY 1993

Oculus Rift

Oculus Rift

Flat 1080P

AMOLED

Display

Accelerometers

and logic boardLenses

Oculus Rift Components

Oculus Rift DK2 2014

Steam VR 2015

Crescent Bay 2015

Virtual Reality

• Tracking and sensor response

• Algorithmic computational time

• Data capture

• Heat and power (de-tethering)

• Economy

Oculus Rift Angular Rotation

Distortion Strategy

Oculus Rift Distortion Strategy

Oculus Rift Distorted Image

Oculus Rift Distorted Image

1 2 3 Catch Autodesk

Project Beyond Samsung 2015

Project Beyond Samsung 2015

Google’s Recording Rig 2015

End..