[Screendoor effect] pentile vs rgb

Considering that the Rift magnifies the display large enough to see individual pixels (the primary source of the screendoor effect), until PenTile displays are available at MUCH higher resolution, such displays would be a horrible compromise over the current RGB subpixel displays:

"shows more pixelation and grain than that of a standard resolution display (i.e.: EVO 4G, DROID X, Nexus S, etc.), thanks to the PenTile subpixel layout. ... If you pay close attention to these displays, you will begin to see the checkerboarding effect in areas of high contrast or high saturation. ... PenTile displays are not all bad; they actually come with several advantages over competing technology. For instance, your standard RGB stripe is just that, a stripe with red, green and blue subpixels to each pixel. PenTile technology uses 33 percent fewer subpixels (two per pixel) and adds a white subpixel that gives the image added brightness and can aid the display in brighter or whiter color reproduction. ... Nouvoyance, the creators of PenTile, also explains that with their technology, "'pixels' in the traditional sense have been eliminated in PenTile RGBW™ displays; individual subpixels are not restricted to use in one pixel group, but instead participate in multiple 'logical' pixels in their surrounding vicinity." ... If you can look at a PenTile display and not see the checkerboarding or pixelation, or you want something with a little extra battery life, a phone with a PenTile display will suit you well. Personally, I take one glance at the display and I can see checkerboarding from an arm's length. The more I use a PenTile display, the more I see pixelation and the more it messes with my eyes. PenTile is not all it's cracked up to be by Nouvoyance and it's not as bad as some people make it seem. It's a good middle-of-the-road display with a few benefits of its own.

A similar conclusion from a (perhaps) more authoritative source:

"

I'm aggree with you on the less subpixel thing.
So the pixels shoud be "more visible".

But what i'm thinking is that he problem isn't so much the "pixel being visible" than the "GRID" aspect, with lines.

I'm agree with you that on a RGB the pixel will be less visible than pentile.
But as long as we already see the pixels... two other aspects have to come into consideration :
What do we see exactly, what kind of do we perceive ?



I want to have two axes of reflection, before taking my definite conclusion :

1) About the colors.
The screendoor effect is annoying not only because we can see pixel, but also because the visible pixels have a lot of color contrast beetween each other. so we really see individual dots.

Some Pentile, sometimes use white pixels.
If we're already in a situation where we can see the pixels even in RGB.
Don't you think that "white" pixel, would be less terrible to look, in opposition to high contrast RGB subpixel?
A white pixel (in the philosophy of pentile) is already a kind of "melted" subpixel
Where it got critizided cuz there is less information and its a little more blurry... Its maybe what we want in this scenario, having something giving the correct perceived color information (pentile philosophy) without looking like high color contrast Red, green, blue dots


2) About the shape.
the screendoor effect is really annoying not only because we can see the pixels... but because of the GRID effect.
vertical/horizontal line everywhere.
Maybe the new pentile shape, and different subpixel Size could help killing this grid Effect.
We would effectively still see the subpixel, but if we choose the Diamond matrix there is not more such things as "lines".
So there is "Dots" yes, but not the "grid" aspect anymore.


I hope i explain good, cuz i always have some trouble to communicate ideas in another language, in such technicals discussions.





But pentiles style are numerous... so there is a lot of situation to inspect.

I hope to have you opinion on this

I just did an interesting experiment related to this last night. I rendered scenes to a checkerboard pattern, replacing "red" pixels with my images. I left all the "black" pixels black. When viewing video content on this, the "screendoor" becomes diagonal instead of being a grid of vertical and horizontal lines. Even though I only used half as many pixels, this made the perceived screendoor effect mostly go away. This was actually a side effect of changes I made to the "Mountains" shadertoy to make it work well on my Rift with SBS partial overlap (which is awesome, BTW). I spent too much time viewing that in my Rift. Next, to add head tracking. I did NOT use pre-warp, and like others have posted, that seems somehow to not cause motion sickness... Somehow that seems counter-intuitive. EDIT: I just changed the cameras to be about 10,000x closer together. Now the mountains and trees look MUCH larger, and it did make me dizzy. Perhaps my morning coffee contributed to perceived motion sickness?

Now here is why this checkerboard experiment is useful to this thread:

My eyes seem more as perceptive of of lines that are near horizontal and near vertical. This was also a reason why the XO/OLPC displays (later Pixel Qi) use a diagonal pixel grid. The perceived resolution seems higher when pixel boundaries are not aligned parallel or perpendicular to the horizon.

I also implemented checkerboard interlaced rendering many months ago (before I even got my Rift) in an effort to increase framebuffer rendering speed. I also noticed how it seemed to lessen perceived screendoor effect back then too (although only when the view is rotating). During a stationary view pixels do not change and screendoor is again visible.

PenTile also uses a different grid, which may help remove screendoor effect to some extent, but as mentioned earlier it needs much higher resolution to overcome annoying visible artifacts of its own.

what I like about the pentile GS4 diamond
Is that there is NO dark line.
neither vertical, horizontal, diagonal..
So there is absolutly no way to see a grid.

I know there still will be "something" undefined, lack or resolution, but I dont know how much impact it would have
on this "screen door effect" and how much degradation it woud cause.

If benefits would be higher than problems.
I think it would, by far.. but i have no way to test or proove that.

"Tgaud" wrote:
what I like about the pentile GS4 diamond
Is that there is NO dark line.
neither vertical, horizontal, diagonal..
So there is absolutly no way to see a grid.

I know there still will be "something" undefined, lack or resolution, but I dont know how much impact it would have
on this "screen door effect" and how much degradation it woud cause.

If benefits would be higher than problems.
I think it would, by far.. but i have no way to test or proove that.

Like most things, things in practice are often not as predicted in theory. The only way to fairly evaluate different display technologies is in a side-by-side comparison, and statistically evaluated by a large number of people due to subjective preferences. There are already people who love PenTile in smartphones, and others who dislike it. This "rift" in differences of opinion will only be magnified by HMD lenses.

This all reminds me of a time long ago when I was toying with the idea of my own game-system. I was designing the video system to address/signal individial pels (we now refer to as subpixels) in a hexagonal array, because that's what I thought TVs (CRT) used -- I thought the shadow mask was a hex grid (actually circles). I think that was even older TVs because I ended up finally looking at some TVs up close and most were |R|G|B|. This was disappointing because I was expecting the added apparent resolution would be great (I was miffed when cleartype was hailed as something miraculous!), as well as the narrower angle (60deg) between natural lines.

So, this kind of arrangement: (*Edit: fixing alignment)
..BRGBR
.RGBRGB
..BRGBR

And now I can't even find reference to it. Except hinted at in some patents referring to a shadow-mask of hexagonal type.

All of the subpixel arrangements you showed in your first post would produce a noticeable screendoor effect. The screendoor effect does not just come from dead space between pixels, but from the different brightness (either perceived or actual) of different colours of light.

For example, the Rift display today has effectively no dead space between subpixels on the horizontal axis, and a large amount of deadspace between pixels on the vertical axis. You might think that this means that the screendoor effect should only be visible in one direction, where the black gap is. But when you use the thing, you actually see it on both axes. This is because the green subpixel seems much brighter than the red or (most of all) the blue. So your eye interprets that difference in brightness as a gap, and you end up with a full 2D grid screendoor effect.

In the particular RGB arrangement of the SGN2, you'll perceive a 2D grid screendoor effect (even looking at the macro picture you can) because the green is spaced out and much brighter than the red or blue. In the RGBG pentile arrangement on the SGS3, you'll see a primarily vertical screendoor effect (between vertical columns) because the green pixels are all lined up and largely touching, but are thinner and much brighter than the red/blue beside it. In the SGS4, the diamond pentile arrangement would produce an effect similar to the SGN2, where the grid of green pixels is primarily visible, leading to a perceived 2D grid screendoor.

There isn't really any possible subpixel arrangement that would completely eliminate the screendoor effect. Using a panel with minimal dead space would help, but the only real solution is to increase the panel resolution. A diffuser might help, but that's tricky to get just right. Besides, in my experience, the screen-door effect isn't nearly so distracting as the super low resolution producing a super low detail image.

I'm not agree with your statement.

If what you say is true, (one some screen one subpixel is brigther than the other) It would meant that the perceived color would be false.

You can't disassociate : subpixel brithness / eye sensibility to each color(different for each) / size of each subpixel according th his color.

they play with shape and brigtness to get the screen have more longetivity. but in any case the final perceived pixel color effect is the same.

Yo do have space beetween pixel, and its indeed what you perceive.
IF what you say were true, we would see a screendoor difference when looking a whole blue/red/green image (even when the subpixel color you name are off) , but there is not. The screen door is always present in sames circonstances.

"Tgaud" wrote:

Yo do have space beetween pixel, and its indeed what you perceive.

As I've posted before on here, this is a photo I took of the rift panel (direct shot of the screen, not through a rift lens). There is not enough space between pixels horizontally to be noticeable.




I just tried looking at my Galaxy Note 2 using a rift lens. The screen door effect is still there. Not as bad as the rift, but still visible.