Lesson 2 - What is VR

Question 1

focus how?

Answer 1

lenses

Question 2

low persistence

Answer 2

only showing portion of image

Question 3

imu

Answer 3

intertial measurement unit

Question 4

summary

Answer 4

What is virtual reality?
Virtual reality is the creation of a synthetic, believable virtual world that is made possible by hardware and software.

What hardware is needed for virtual reality to work?
Hardware components include two lenses, a display panel or two and some sort of tracking hardware.

Lenses
Lenses help us focus on the displays that are really close to our eyes. They magnify the image to ensure that we can see everything.

Display Panels
Display panels are the component that will actually display the image that we’re going to see. Some hardware, like the Oculus Rift, Oculus Go, or HTC Vive, use embedded display panels. The display panels are included in the headset. Other hardware uses a phone as the display panels. For example, Google Cardboard, Google Daydream, and GearVR use a phone to do display the images. Display panels need to have a very high resolution and support low persistence. In order for a resolution to be as good as a photo, a display panel in a headset would need to have 16,000 by 16,000 pixels. For comparison, the HTC Vive has a resolution of 1080x1200. We have a long way to go! The low persistence is needed because this will help ensure we see clear visuals when rotating our heads in VR. It prevents what’s called “motion blur”. Since OLED pixels don’t change color fast enough, low persistence updates a small portion of an image at any given time, making the visuals clear as we turn in VR.

Tracking
VR requires some sort of tracking in order to work. Inertial Measurement Units (IMUs) are the chips that are used for tracking rotation. Google Cardboard, for example, would use IMUs to track our rotation as we move the headset around. The only drawback of this type of tracking is that IMUs don’t track position. To track our position in the space, we must use other techniques. Some headsets use cameras, lasers, or magnetic fields to track our position.

What is simulator sickness?
One of the most common challenges of developing for VR is called “simulator sickness” (or sim sickness). This is where someone gets sick (dizzy, queasy, or headaches) from a VR experience. Sim sickness is caused because there’s a mismatch between the body’s internal sense of motion and what we see.

How did we get to where we are with VR?
A very brief timeline: 1838 → The Stereoscope is invented by Sir Charles Wheatstone. This is our first foray into 3D graphics.

1968 → The Sword of Damocles is invented by Ivan Sutherland. His invention tracked user head motion and overlayed vision with synthetic computer generated graphics of primitive 3D object wireframes.

1990s → VR was first promoted to the general public but the devices didn’t live up to expectations.

2012 → Oculus Rift Kickstarter is launched and backed. Oculus would later be bought by Facebook for $2 billion.

2014 → Google Cardboard released.

2016 → Google Daydream was announced.