Why is VR resolution considered to be 'low'?

It may seem like a weird question, but when we have headsets like the Reverb and even the Index having resolutions higher than most people's monitors, why do we still talk about the 'low resolution' of VR headsets?

I'm sure the answer is obvious, but...

Can VR give me 2560x in each eye on an average computer?

Can VR give me 2560x in each eye on an average computer?

Sorry, I don't understand how that relates to my question.

@Imacken

simple answer is, that the displays in VR are right in front of the eye, what causes to detect the pixelmatrix of the LCD/OLED.

I´ve read once of micro displays especially designed for the purpose of use in VR headsets, but next thing then will be to invent a better lens technology to enlarge the microdisplay´s image - but that´s more in research than development.

Anyway, back in the 80s no one complaint about having a 15" CRT monitor for flight sims with 800 x 600 resolution, but the image quality of VR today has to stand a comparison with 4k UltraHD LCDs monitors, what in my opinion, is not quite the same thing.

Yeah, it’s not the resolution, as such.

It’s the fact that your eyes are so close to the displays. When using a traditional 2D monitor, even if it’s a 36” inch screen, the view is much smaller than in real life. In VR it’s full scale. Imagine having a 50” 4K display, and then moving so close to it that the view fills a 100° of your field of view, and the virtual cockpit becomes as large as in real life... You’d want more than 4K res too ;)

@Imacken

simple answer is, that the displays in VR are right in front of the eye, what causes to detect the pixelmatrix of the LCD/OLED.

 

I´ve read once of micro displays especially designed for the purpose of use in VR headsets, but next thing then will be to invent a better lens technology to enlarge the microdisplay´s image - but that´s more in research than development.

 

Anyway, back in the 80s no one complaint about having a 15" CRT monitor for flight sims with 800 x 600 resolution, but the image quality of VR today has to stand a comparison with 4k UltraHD LCDs monitors, what in my opinion, is not quite the same thing.

Thanks for that. Not sure I see the answer though. I use a 4K monitor in DCS as well VR headsets. Currently I use the Index supersampled to 2880x3200 per eye, and don't really have any issues with the res.

I've always felt, from my perspective, that the issue with VR headsets has been SDE not resolution. For example, my current Index has the same 'resolution' as my Vive Pro, but the difference in image quality - and perceived resolution - is huge, partly due to massive reduction in SDE, and use of sub pixels with the RGB display.

I'm not convinced by the 'close to the eye' point either. I mean, sure back with CV1s etc., maybe, but now? I can't see individual pixels easily on my Index, and I couldn't see them when I had a Reverb either.

I certainly think it is distance as others have said. Going back to back between VR and a 4k monitor and the difference is still huge, we need much bigger resolutions at the distance we are from the display.

You´re right, me too don´t see the SDE with P5k+. It also makes a difference between OLED, like the Vive Pro and LCDs. The distance between the pixels in LCDs is less observable than with OLED.

SDE and display resolution are in direct relation, but there are additional technologies, like kind of SDE filter Samsung´s Odyssey+ has; the Index also got kind of such filter between the display and the lenses.

But the distance from the eye to an LCD/OLED projected image is critical to see/not see pixelation. The higher the resolution, the closer you could get to the display without seeing the pixels. With TVs, Monitors or mobile phones, it is not so much of an issue, but with LCD beamer and now with VR headsets it is.

Luckily the SDE is not so much of an issue today compared to the first VR headsets Rift and HTC Vive, but the presentation of details in the depth of the image still is depending of how much pixel/subpixel are available to properly render the geometrical shape and texture in detail. Today´s VR games avoid these details in distance or at all to not have this problem, but with DCS we are on the opposite end of line.

Beside pure resolution of the hardware, there are also AntiAliasing, and what not, to counteract the impression of pixelated images, but on the bottom line freely cited John Carmack, there would be needed a resolution of 16k in VR headsets to get rid of any pixelation.

All good comments, and yes, of course, we would all want more resolution.

My question was really why is the current resolution often called - and commonly believed to be - low when it's not.

I'm not saying that we are at 4K monitor parity in quality and clarity of image, but whatever the perceived limitations of VR are, it is not low resolution in terms of pixels compared to many monitors.

Yeah, it’s not the resolution, as such.

It’s the fact that your eyes are so close to the displays. When using a traditional 2D monitor, even if it’s a 36” inch screen, the view is much smaller than in real life. In VR it’s full scale. Imagine having a 50” 4K display, and then moving so close to it that the view fills a 100° of your field of view, and the virtual cockpit becomes as large as in real life... You’d want more than 4K res too ;)

Exactly..it's the scale. Simples :)

... I would say, it´s even crazy compared to a monitor, on what resolutions we´re running the headsets and at what level of supersampling in addition. Not only for one, but for two images simultaneously.

It may seem like a weird question, but when we have headsets like the Reverb and even the Index having resolutions higher than most people's monitors, why do we still talk about the 'low resolution' of VR headsets?

I'm sure the answer is obvious, but...

Because it is question of pixels per degree of your field of view. So you have a nice 32" 4K monitor and it's picture is crisp. But how much of your field of view is covered by your monitor, or, to put it another way, how many monitors would it take to cover your field of view completely? Probably around 10 monitors at least. With each being 4K pixels long, 2K wide or 8K pixels in terms of its area.

Now imagine that you are using a single 4K monitor that is the size of 10 32" monitors - to cover your entire FOV. Each of its pixels would be 10 times bigger and it would look nothing like the crisp picture of a composite arrangement made up of 10 4K monitors.

I hope this made sense.

Perhaps another couple issues includes the "quality" of a pixel - how many subpixels are there and the amount of black space around them plus their light intensity and color range - and then the imperfect quality of the lenses that we look through to see those pixels at such a short range. On top of that is the amount of graphics predistortion required to make the image seem correct after all the lens distortion. A monitor doesn't have to deal with most of these issues when viewed from a couple feet. Also, due to the high graphics performance required to avoid VR sickness and to provide for smooth scene movement when turning the head, we have to make some compromises in graphics settings that we prefer to use with a monitor and non-stereo operation. It's not just pixel dimensions that make up quality. Most of the time, when we use a monitor, we are looking at about 60 degrees field of view instead of the 100 degrees in VR - this goes to the (sub)pixels per degree issue as well.

Whew - I'm glad that it actually works pretty well!

Because it is question of pixels per degree of your field of view. So you have a nice 32" 4K monitor and it's picture is crisp. But how much of your field of view is covered by your monitor, or, to put it another way, how many monitors would it take to cover your field of view completely? Probably around 10 monitors at least. With each being 4K pixels long, 2K wide or 8K pixels in terms of its area.

Now imagine that you are using a single 4K monitor that is the size of 10 32" monitors - to cover your entire FOV. Each of its pixels would be 10 times bigger and it would look nothing like the crisp picture of a composite arrangement made up of 10 4K monitors.

 

I hope this made sense.

We have strayed way off what my original question was meant to mean!

However, to take up your point, I'm really not sure what you are getting at. You're not looking at the entire FOV in VR, only about 100 degrees at a time. More than a monitor, but a long way off 360!

We have strayed way off what my original question was meant to mean!

No, we have not.

You seem to be ignoring the answers provided to you. Take your monitor. Now get your face to an inch in front of it. What happens to the perceived resolution?

Might have already been mentioned but I didn't see it but in VR the effective resolution is basically half of its stated value because the left/right screens (or sides of the panel) are generating nearly the same image for stereoscopic 3d.

Between that and pixels per degree of fov is why VR requires so much higher resolution to be on par with seemingly equivalent monitors

Also the pixels aren't evenly packed like a monitor due to the warping required which is why SteamVR adds another 1.4 factor to native resolution, to ensure the centre is clear.

(...) You're not looking at the entire FOV in VR, only about 100 degrees at a time. More than a monitor, but a long way off 360!

The magic of VR starts, when you get the impression, that you are really in a 360° computer graphics environment, but in fact there is only rendered the part of the 360° impression, on what you are looking at. This part you are looking is determined by the FOV your headset. A human got a natural FOV of approx 210°. The more FOV the headset provides, the more natural the impression in VR gets.

Or let´s put it this way: while in reality and in 360° VR filmed material the 360° environment ( real or as filmed material ) does exist, even when you´re not looking at, in computer graphics VR only exists the part of the environment you´re currently looking at, which is rendered in real time.

@Thadiun Okona

The industry sometimes used to define the resolution of their VR headsets as combined, like 2880 x 1600 instead of the resolution per eye 1440 x 1600. This is more or less confusing, but 2880 sounds more than 1440 for marketing reasons.

Technically, with regard to the resolution of the display and not the rendered images, it is correct when a headset uses one single display only, which is split into two images, but some uses actually two displays, one for each eye. The perceived resolution is always the resolution per one eye, 1440 x 1600 in this example. The magic of 3 dimensional VR ends, when the two images are put together as one in the brain.

The magic of VR starts, when you get the impression, that you are really in a 360° computer graphics environment, but in fact there is only rendered the part of the 360° impression, on what you are looking at. This part you are looking is determined by the FOV your headset. A human got a natural FOV of approx 210°. The more FOV the headset provides, the more natural the impression in VR gets.

Or let´s put it this way: while in reality and in 360° VR filmed material the 360° environment ( real or as filmed material ) does exist, even when you´re not looking at, in computer graphics VR only exists the part of the environment you´re currently looking at, which is rendered in real time.

Yep, exactly. That was my point to Katmandu.

Pixels per degree of fov. Vr has much more FOV than monitors. Then add the fact that you need to render 2 scenes vs just 1 for a monitor.

We have strayed way off what my original question was meant to mean!

 

However, to take up your point, I'm really not sure what you are getting at. You're not looking at the entire FOV in VR, only about 100 degrees at a time. More than a monitor, but a long way off 360!

Ok, my point was not about any particular VR set, some have FOVs of 170+ (?). However, I also thought about Oculus style FOV when I said about 10 monitors stacking to fill the 100deg viewing space.

Another way to think about pixels per degree is to compare the crispness of a 1080p phone and 1080p 32" tv screen - same resolution and number of pixels, but covering wider area leads to increase in pixel size and decrease in perceived crispness. Same issue with VR where 4K total pixels (2k *2K in case of Reverb) make up a 100"+ tv (required to cover 100deg FOV) so to speak.

Ok, my point was not about any particular VR set, some have FOVs of 170+ (?). However, I also thought about Oculus style FOV when I said about 10 monitors stacking to fill the 100deg viewing space.

 

Another way to think about pixels per degree is to compare the crispness of a 1080p phone and 1080p 32" tv screen - same resolution and number of pixels, but covering wider area leads to increase in pixel size and decrease in perceived crispness. Same issue with VR where 4K total pixels (2k *2K in case of Reverb) make up a 100"+ tv (required to cover 100deg FOV) so to speak.

Of course, that is all true. However, in your example, no one would describe the phone or the TV as ‘low res’. That is the essence of my original question. It’s the perception of VR being ‘low res’ that I was questioning, not the technicalities of why the same res in a VR headset looks ‘lower res’ than the same number on a monitor.

Just about the terminology, really.

Of course, that is all true. However, in your example, no one would describe the phone or the TV as ‘low res’. That is the essence of my original question. It’s the perception of VR being ‘low res’ that I was questioning, not the technicalities of why the same res in a VR headset looks ‘lower res’ than the same number on a monitor.

Just about the terminology, really.

First, most people are mistaken by marketing and use resolution to compare headsets.

What matters for fine details is pixels per degrees (PPD) count.

For instance, if you take Index and Rift S vertical resolution divided by vertical FoV* (because no overlapping on vertical plan) you have the same PPD for both headset.

* I took the FoV measured by the same tester in the same "virtual lab".

Why we need more resolution in headset than on scree ?

Because we are playing at scale one, the headset screen are so close that we can see individual pixel. We can see the space between the pixels (black lines = grid effect).

I would rate headsets compared to screen like this:

- CV1/ Vive: 1024x768 graphics

- Reverb: most people consider it as good as full HD screens.

- Rift S/ 5K+/ Index: between the 2 previous.

Actually a game designed to be played on 1024x768 is good enough.

But DCS World graphics have been upgraded to be played on full HD or higher resolution screens (4K) before VR became current.

We are struggling a little bit to see fine details with Rift S and the like, but I consider it good enough to be used in tactical situations.

Then there is the problem of the lenses and physical adjustments.

You can have the best screens in the world, it would be ruined by poor lenses.

The sweet spot (area where everything is sharp) makes a huge difference.

This is well known in photography, the farthest you are from the center, the more blurry it gets. The lens which are sharp edge to edge are the most expensive.

I wouldn't call the reverb HD. Its just the current best res wise. It center res is close to my 24" 1080p monitor from 2-3ft. But I can still see mura, SDE and chromatic abberation if i look for those things. Plus it blurs out when looking off center. I figure gen 2.5 sets that come in the next year or two will work to fix those issues.