He starts talking about SDE at 6:11 in the video. He says there’s more SDE “probably because it’s uniform throughout the entire lens, as opposed to the Rift and the Vive which they focus on the center to be the highest and that’s where it’s the least noticeable”.
So he blames the lenses. He doesn’t talk about PPI or did I miss a part ?
BTW, at 7:25 he talks about the a smoothing filter in the OSVR HDK2, which causes a blurring effect, which lessens the SDE. This also happens in the Pimax ! In the Pimax we have the shutter glasses, if you take them out the SDE becomes a lot more noticeable. So in the Pimax 4k it’s also a trick: less clear image = less noticeable SDE.
On diferent issue which I mention it as well before on asumption how could workVR on that small 3000PPI display. Higher magnification increasing blurriness out of center on peripheral. this is strictly lens problem and lenses don’t have nothing with SDE. Do you know what it SDE at all and how it is made?
Kopin is workin on special lenses for their 3000PPI panel headset. They obviously think it can be done, and I’m sure they’re right. We’ll see Q1 next year probably.
Sorry you’re losing me here, not sure what your point is, elaborate please.
Another way of looking at it is this: when you’re looking at a display through a lens, you don’t see the actual display. You see a ‘virtual image’, a version of the display that your lens created. Now the amount of pixels you have in ANY image, either real or virtual, is the main factor in SDE. So if you have 300x300 pixels in a real or in a virtual image (blown up to ‘real’ proportions), it’s still the same SDE.
OK now when this is separate thread lets start from begining and determine what is what and how it is effecting on VR picture in general.
SDE or in full name Screen Door Effect is term used for effect your picture is look like you are watching true door with mosquito net on it (Screen door).
What is cause of this issue?
Any display is made from physically small squares separate with thinly black lines whot create this visible grid what creating SDE. That is the only reason for SDE. When we look at displays from sertan distance we can’t see this grid but when we come closer this grid start to be more noticeable. Density of this cubes is measured by the number of pixels one square can reproduced and it is determine in PPI. Higher PPI smaller square are and that is mean smaller grid.
VR is using optics to virtually enlage the screen so this enlargement is scaling up this squares and grid what it making it more noticeable.
How much SDE is noticable also effecting lenses by radial blur but this just masking SDE by decreasing quality of the picture.
To compare this best example is the Vive and CV1. You can notice on comparing VR’e SDE that Vive have better sharpnes but CV1 less noticeable SDE even got technically exact same screens. Point is CV1 using trick whot DK" users was hacking to reduce SDE effect by put plastic film on display which was blurring the picture and this blur was made this grid less noticeable.
Only thing what fiscally reducing SDE is higher PPI
Lenses effecting only on picture quality and problem of the lenses are radial blure, FOV and God rays.
IPD is effecting on sharpenes of the picture and 3D effect. Effect on SDE is minor and secondary.
SDE is strictly hardware issue and depend on display quality.
Due to size of display and needed magnification this 3000PPI is like 5.5" display with 900 - 1000 PPI but problem is lenses. You can’t reach quality with standard magnifying lens. They will need special made lenses for this purpose. Doable but this raising cost of the production so it is questionable are they reach desired results for affordable price. There is still too much question about this product and no real prototype which will answer on some of them. We need to see first testing. It is too early for judgement.
Agreed. There’s a common relationship between the pixel size and the lines between that cause the SDE. So the smaller the pixel, the smaller those lines and the less SDE. We totally agree on that.
Again, we agree here.
Exactly. Less quality of the visible image = masking SDE.
Exactly. Higher PPI = smaller pixel = smaller lines = less SDE. We totally agree here.
What we disagree though (it seems) is that I say that if you magnify a display planel, then the pixels become bigger and the SDE too. So if you have a panel with very high PPI, but magnify it a lot, then the net effect will be 0. Hence, it’s not about the PPI of the source (the panel), it’s about the PPI of the virtual image that the lenses create. Very high PPI of a panel means nothing if the panel is so small that you need to magnify it very much. PPI of the panel only means something if you specify the panel size too (and the FoV). But it’s better to just ignore it and look at the resolution, that’s all you need to know (together with FoV)
Also look at it this way: what’s the size of the ‘virtual image’ ? It’s not expressed in cm’s or inches, but its expressed by the ‘FoV’ ! So if you know the resolution and you know the FoV you actually have what would correspond to the PPI of the ‘virtual image’.
That is exactly what I’m talking as well all the time so don’t know where is the problem? I even take comparison of the HP/ACER MR with Vive/CV1 where this issues are clearly noticeable. And we are talking about here in small difference in size where higher magnification cosign higher SDE feel and higher radial blurs.
Basicali let put it this way. We are in pursuit for VR PPI, lets call it this way. What should be VR PPI? I will put here video which explaining Apple retina display what is nothing else than fancy name relations of display PPI and distance from where you are watching this display. All this relations we have in VR as well but they goes true lenses as well.
So in VR we are simulating large screen from some distance. To get realistic PPI in VR we need divide display PPI with magnification factor of the lens. so for example take Pimax4K which got 807 PPI and lens magnification 3x (I don’t know what is real magnification no one cover it yet on any VR HMD) , this will be 807/3=269 This is probably that VR PPI of 269PPI.
So only in this way we could compare SDE between various VR HMD’s.
To predicz possible SDE on Kopin 3000PPI display so it is really small display so you will need magnification around 10x. 3000 / 10 = 300 VR PPI so this 3000 not look so much any more and it is questionable did they reach desired quality of the picture in general in the end?
Again wrong. You are in constant contradiction with your self. That is the point Resolution is more software than hardware issue.
DK2 have terible SDE or HDK 1.4 or PSVR they are running on 1080p but you can SuperSampeling it even to 4K. This will increase some details and over all quality but SDE stays the same because it is display hardware resolution what make SDE.
Are you talk about SDE or picture quality. SDE don’t have nothing with resolution it is always the same no matter whot resolution you are running.
Of course I’m not talking about a software render resolution, I’m talking about the native panel resolution. This is the only important factor because:
Hmm I think I know the misunderstanding. You seem to think I’m talking about some software resolution. I’m not talking about ‘which resolution you run’, when I’m talking about resolution I’m talking about the native (hardware) screen resolution: the amount of horizonal pixels * amount of vertical pixels: the screen resolution as advertised by the manufacturer.
That’s exactly what I’ve been saying before. PPI doesn’t matter, what counts is PPD (PPI is about the panel, PPD is about the ‘virtual’ image, or the image that you see through the lense). I’ve said it like this:
They call it “PPD”, I really like that term ! That’s what people should use when talking about SDE in VR.
Also watch the video they’ve posted about how their headset uses much more of the available pixels on the display. That’s exactly my point that I’ve made with the soft IPD adjustment above
