[VR/AR] How to Pass the Visual Turing Test in AR/VR (2)

[VR/AR] How to Pass Visual Turing Test in AR/VR (1)

 

🔼previous posting🔼

1. Beyond varifocal : Retinal resolution, distortion-free displays, and HDR
- Butterscotch: Understanding “retinal resolution”
- Eliminating optical distortions in VR headsets
- Starburst: Previewing high dynamic range headsets

2. Realizing the step change
- Holocake: How low can you go?
- Mirror Lake: Bringing it all together

Beyond varifocal : Retinal resolution, distortion-free displays, and HDR

resolution, soptical distortion, dynamic range

Butterscotch: Understanding “retinal resolution”

“Retinal resolution” has long been the gold standard for products with a screen. Although there’s no universally accepted definition, it’s generally considered to be around 60 pixels per degree (ppd), which is sufficient to depict the 20/20 line on an eye chart. While most laptops, TVs, and mobile phones have long since passed this mark, VR lags behind because its immersive field of view spreads the available pixels over a much greater visual extent. (VR은 몰입형 시야가 사용 가능한 픽셀을 훨씬 더 큰 시각적 범위로 확산시키기 때문에 뒤처집니다.) For example, Quest 2’s displays deliver about 20 ppd.

 

 

sense of realism steadily increases as image resolution increases, all the way to around 120 ppd, well beyond what is considered “retinal” resolution. → high-resolution VR을 만드는 것이 중요함.

Eliminating optical distortions in VR headsets

optical abberrations(광학 색수차)

Some aberrations can be corrected by warping the image in software — that’s a crucial element of virtually every VR headset today, and getting it right is key to great visual experiences. However, the distortion correction software in current VR headsets doesn't work perfectly; the correction is static, but the distortion of the virtual image is dynamic, changing depending on where one is looking.

 

pupil swim: can make VR seem less real because everything moves a bit when the eye moves.

https://www.youtube.com/watch?v=lN5xVSC7bz0

DSR은 이 문제를 해결하기 위해서 lens fabrication hardware보다는 speed of optical design software 연구를 하기로 함.

 

DSR’s VR lens distortion simulator: emulate VR headsets using a 3D TV. This allows the team to rapidly study novel optical designs and distortion-correction algorithms in a repeatable, reliable manner while also eliminating the time-consuming process of iterating on design using full headset prototypes.

https://www.youtube.com/watch?v=HKc0-qPknJY

 

dynamic distortion correction uses eye tracking

Starburst: Previewing high dynamic range headsets

high dynamic range (HDR) is the single technology that has been most consistently linked to an increased sense of realism and depth. HDR refers to support of wide ranges of brightness, contrast, and color.

“Nits” are units that describe how much light an object emits

 

DSR’s Starburst prototype : placing very bright lamp behind the LCD panels. reaching a peak brightness of 20,000 nits.

https://www.youtube.com/watch?v=Mi0QNEDVdjU

 

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Realizing the step change

Holocake: How low can you go?

Holocake 2 : is designed to test the optical performance of holographic pancake lenses in fully functional.

• the thinnest and lightest VR headset we’ve ever built. ultra-compact form factor. reducing the size of the headset
• a fully functional, PC-tethered headset
• make it possible to place the lens much closer to the display

Holocake 2 - YouTube

(기존 VR 렌즈) Today's VR displays rely on a light source, a display panel that forms images by dimming or brightening the light, and a lens that focuses the light from the display into the eye. Typically, the lens needs to be a few inches from the display in order to have enough focusing power to direct the light into the eye.

 

(Holocake lenses) Holocake lenses reduce thickness and weight in two ways. First, polarization-based optical folding causes light to reflect inside of the lens, similar to emerging pancake lenses. Second, holographic films replace the bulkier refractive lenses used in both pancake lenses and conventional refractive designs, like Quest 2. In each case, light coming from a flat-panel display is focused towards the eye; only the form factor varies.

 

Holocake 2 applies two technologies in tandem to accomplish this. First, it replaces the lens with a holographic optic that bends light like a lens, but is shaped like a thin, transparent glass slab. Second, it implements polarization-based optical folding (emulating a pancake lens, but with the much smaller form factor of a holographic optic) to dramatically shorten the path of light from the display to the eye.

 

Holocake headsets require specialized lasers, rather than the LEDs used in existing VR products.

Mirror Lake: Bringing it all together

• the slim electronic varifocal modules from Half Dome 3 can be added to resolve vergence-accommodation conflict without significantly adding to the thickness of the headset

⭐ Half dome: using Fresnel lenses that supports a 140° field of view. by physically moving the screens based on eye tracking, it ensures that the image remains sharp, even when inspecting close objects.

• And instead of requiring bulky prescription lens attachments, individualized vision correction is just a matter of attaching another thin lens to the front of the headset, or even baking the wearer’s prescription directly into the hologram used in the main Holocake lens.
• a pair of front-facing cameras that enable machine-learing-driven passthough
• Eye tracking: using holographic films to redirect light from the eyes towards a pair of cameras. → multiview eye tracking