4 ms·

I don’t understand the pixel per degree calculations. Quest 2 sits at 20.58 PPD in the table, which makes sense, as that’s 1832px/89deg. How do you arrive at a

by w-m 5y ago

I don’t understand the pixel per degree calculations. Quest 2 sits at 20.58 PPD in the table, which makes sense, as that’s 1832px/89deg. How do you arrive at a 35.5 PPD for the Simula VR with 2448px for 100 deg fov? It links to a [2] in the table, but there’s no [2] I the references.

kanetw 5y ago
We use variable magnification for the lenses. That is, the foveal region has a higher PPD and the periphery has a lower PPD. As your eyes follow the same pattern (your fovea has a high resolution, everything else drops off sharply), it's basically a free PPD gain. I put a link to the paper [1], but it's paywalled. [1] https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10335/103350G/Super-resolution-optics-for-virtual-reality/10.1117/12.2270178.short?SSO=1 https://www.spiedigitallibrary.org/conference-proceedings-of...
- wlesieutre 5y ago
  Except that your fovea moves around with your eyes and this is glued to looking straight forward. You get PPD gain if you're looking at the same thing that your face is pointed toward, at the expense of when you look off to the side. Not exactly "free" but probably worth the tradeoff. How big a "sweet spot" do you have in the center? Enough to read lines of small text without rotating your head back and forth?
  - kanetw 5y ago
    About +-15 degrees. This accounts for 86% of saccades. I need to confirm how sharply it drops after that, but in any case it should be above 20 PPD +-(15 to 30) degrees and above 12 PPD for +-(30 to 50) degrees.
- w-m 5y ago
  This seems a bit disingenuous, listing the max/center PPD for your product, and the average PPD for the Quest.
  - kanetw 5y ago
    No other headset except the Varjo Aero use this technology, and only the high-end Varjos have a focal view display (1920x1920 in the central 27 degrees). Rest is basically uniform throughout. We use the peak PPD for the Aero.

by w-m 5y ago

kanetw 5y ago

We use variable magnification for the lenses. That is, the foveal region has a higher PPD and the periphery has a lower PPD. As your eyes follow the same pattern (your fovea has a high resolution, everything else drops off sharply), it's basically a free PPD gain. I put a link to the paper [1], but it's paywalled. [1] https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10335/103350G/Super-resolution-optics-for-virtual-reality/10.1117/12.2270178.short?SSO=1 https://www.spiedigitallibrary.org/conference-proceedings-of...

wlesieutre 5y ago
Except that your fovea moves around with your eyes and this is glued to looking straight forward. You get PPD gain if you're looking at the same thing that your face is pointed toward, at the expense of when you look off to the side. Not exactly "free" but probably worth the tradeoff. How big a "sweet spot" do you have in the center? Enough to read lines of small text without rotating your head back and forth?
- kanetw 5y ago
  About +-15 degrees. This accounts for 86% of saccades. I need to confirm how sharply it drops after that, but in any case it should be above 20 PPD +-(15 to 30) degrees and above 12 PPD for +-(30 to 50) degrees.
w-m 5y ago
This seems a bit disingenuous, listing the max/center PPD for your product, and the average PPD for the Quest.
- kanetw 5y ago
  No other headset except the Varjo Aero use this technology, and only the high-end Varjos have a focal view display (1920x1920 in the central 27 degrees). Rest is basically uniform throughout. We use the peak PPD for the Aero.