More resolution = more revolution

"KingK76" wrote:

"Sebbi" wrote:

"cybereality" wrote:
Going from 720P to 1080P is actually doubling the resolution in terms of the number of pixels.

Doubling the resolution, yes ... doubling the pixel density, no ;-)

I hope the mobile phone/tablet industry will provide us with even more cheap pixels in the years to come. Shouldn't be a problem to render simple worlds in 2560x1600 ... i mean an Android tablet can do it and iPads could probably do it if they had such a display. :)

Okay your comment about going from 1280x720 to 1920x1080 only doubling resolution and not pixel density doesn't make sense to me. If you have a 7" screen with a 720p resolution (1024000 pixels) and then on the same size 7" screen go to 1080p (2073600 pixels) how are you "not" doubling the pixel density? Same size screen+double the pixels=double the pixel density. Is that not correct? If I am incorrect, where is the flaw in my logic. Please explain. :|

Well, yeah, if you measure "pixel density" in Pixels Per SQUARE INCH, then you are correct. But the numbers you are disputing are PPI (Pixels Per INCH), which is like comparing Apples and Kittens (different units of measurement).

So instead, let's compare PPI, which is how "pixel density" is typically measured.

Doubling the PPI would double both X and Y dimensions, which would quadruple (4x) the pixels per square inch. A 1080p display has TWICE as many pixels (2x) as a 720p display, not 4x.

The diagonal 7-inch dimension is only approximate, so I do some rounding here:

1280x720 display PPI calculation:
Horizontal x = 1280 pixels.
Vertical y = 720 pixels.
Diagonal d = sqrt(x*x + y*y) = sqrt(1280*1280 + 720*720) = sqrt(1638400 + 518400) = sqrt(2156800) = 1469 pixels.
PPI = 1469 pixels / 7 inches = 210 PPI.

1920x1080 display PPI calculation:
Horizontal x = 1920 pixels.
Vertical y = 1080 pixels.
Diagonal d = sqrt(x*x + y*y) = sqrt(1920*1920 + 1080*1080) = sqrt(368400 + 1166400) = sqrt(4852800) = 2203 pixels.
PPI = 2203 pixels / 7 inches = 315 PPI.

720p to 1080p PPI increase:
(315 - 210)/210 * 100% = 50% increase in PPI.

What is curious is why doubling the pixels per square inch did not increase the PPI by a ratio of sqrt(2) as I had expected (i.e. 41% increase). Hmm... EDIT: Ahh... I see. 1080p has slightly more than twice the pixels of a 1280x800 display like the Rift DK uses, but the calculations above were for the 720p display (less pixels) that was being discussed. That accounts for the difference between 50% and 41% increase in PPI...
:D

And now, for something COMPLETELY DIFFERENT!

"geekmaster" wrote:
Well, yeah, if you measure "pixel density" in Pixels Per SQUARE INCH, then you are correct. But the numbers you are disputing are PPI (Pixels Per INCH), which is like comparing Apples and Kittens (different units of measurement).

So instead, let's compare PPI, which is how "pixel density" is typically measured.

Doubling the PPI would double both X and Y dimensions, which would quadruple (4x) the pixels per square inch. A 1080p display has TWICE as many pixels (2x) as a 720p display, not 4x.

The diagonal 7-inch dimension is only approximate, so I do some rounding here:

1280x720 display PPI calculation:
Horizontal x = 1280 pixels.
Vertical y = 720 pixels.
Diagonal d = sqrt(x*x + y*y) = sqrt(1280*1280 + 720*720) = sqrt(1638400 + 518400) = sqrt(2156800) = 1469 pixels.
PPI = 1469 pixels / 7 inches = 210 PPI.

1920x1080 display PPI calculation:
Horizontal x = 1920 pixels.
Vertical y = 1080 pixels.
Diagonal d = sqrt(x*x + y*y) = sqrt(1920*1920 + 1080*1080) = sqrt(368400 + 1166400) = sqrt(4852800) = 2203 pixels.
PPI = 2203 pixels / 7 inches = 315 PPI.

720p to 1080p PPI increase:
(315 - 210)/210 * 100% = 50% increase in PPI.

What is curious is why doubling the pixels per square inch did not increase the PPI by a ratio of sqrt(2) as I had expected (i.e. 41% increase). Hmm... EDIT: Ahh... I see. 1080p has slightly more than twice the pixels of a 1280x800 display like the Rift DK uses, but the calculations above were for the 720p display (less pixels) that was being discussed. That accounts for the difference between 50% and 41% increase in PPI...
:D

And now, for something COMPLETELY DIFFERENT!

I figured the x y factor was the key. By the By... After reading how I worded the end of my response I could see how it may have come off as being sarcastic. I was honestly curious about the theory behind it. And boy did you deliver :) That was an awesome answer. You my friend truly are the Master of Geeks... :lol:

"KingK76" wrote:
I figured the x y factor was the key. By the By... After reading how I worded the end of my response I could see how it may have come off as being sarcastic. I was honestly curious about the theory behind it. And boy did you deliver :) That was an awesome answer. You my friend truly are the Master of Geeks... :lol:

Well, if something is worth doing, then it is worth overdoing!




A complete answer that covers all the bases is likely to have the answer you want buried somewhere inside it!

:D

"geekmaster" wrote:

"KingK76" wrote:
I figured the x y factor was the key. By the By... After reading how I worded the end of my response I could see how it may have come off as being sarcastic. I was honestly curious about the theory behind it. And boy did you deliver :) That was an awesome answer. You my friend truly are the Master of Geeks... :lol:

Well, if something is worth doing, then it is worth overdoing!

A complete answer that covers all the bases is likely to have the answer you want buried somewhere inside it!

:D

Just curious... How goes the retina connection?

"KingK76" wrote:
Just curious... How goes the retina connection?

The inexpensive ($56 shipped) iPad Retina LCD panels use connectors that are so freaking tiny that there is no way I can even think about hand soldering wires to those connector pins, so I first need to make a DIY PCB "breakout board" for these LCD connectors.

First, I need to gather the tools and parts I need for a DIY project like this:




And being the DIY homebrew maker enthusiast that I am, I would make my DIY breakout board PCB like this:




Then I can etch my PCBs with DIY etchant, like this:




And then I can solder my connectors to my DIY connector breakout board PCBs like this:




These connectors are much finer pitch (smaller and closer pins) than the example SMT part shown in the above video, but the same soldering technique can be used for these much smaller parts.

So, what is delaying construction of my Retina LCD panel DIY Rift clone is that I need to make a PCB, using the methods shown above...

My, you sure are enjoying that Youtube tag.

"DieKatzchen" wrote:
My, you sure are enjoying that Youtube tag.

Yes he is. And so am I. :D

"eyeiskye" wrote:
I currently own the Sony HMZ-t1 which uses dual OLED screens and has roughly a 70 degree FOV.

The HMZ-T1 has 45deg horizontal, 25deg vertical. The Rift devkit has ~half the pixels per scene spread out across more than 10 times the area.

Once you crank up AA, the current screen isn't too shabby at all with the exception of the screendoor effect.
Completely bearable, but could use future improvement. Still think (2) separate screens for full resolution to each eye would be a nice option... I know it would be a bit more expensive, but as a premium model... I'd certainly buy it.

My question is... just upping the resolution... is that all it takes to get rid of the screen door effect? or ppi? or both?

XD. Well, after finally getting my rift, the resolution issues aren't anywhere near as bad as it sounded like from what people were saying about it.

Given what I've experienced so far, I'd honestly say getting a 120 hz (or faster) display would be much more important than increasing the screen resolution.

However, given that high frame rate displays in small form factors are incredibly rare, and higher resolution displays should be available soon, it may simply be a lot easier to increase the resolution than it would be to increase the framerate...