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Rearranging Pixels For Performance
tepes writes "From bottomquark, A new method of sub-pixel rendering could make monitors cheaper to produce. ClairVoyante Laboratories developed the PenTile Matrix, which uses five sub-pixels instead of the typical three, to take advantage of the fact that the human eye is more sensitive to blue colors."
The human eye is least sensitive to blue. It it most sensitive to green, followed by red then blue. R
I can see this is probably going to be like mp3 compression, where people often say "I can tell the difference between that and the original". So, someone will have to develop something silly like "monitor drivers with more blue!"
-- Dan
As with all slashdot posts, the posting is inaccurate.
The human eye is *least* sensitive to blue... that's what this thing is about, sort of.
It's also not a new method of sub-pixel rendering.. it's a new method of sub-pixel layout.
The theory is that in a conventional LCD, there is too much blue.. it's wasted space, resources, etc.
This thing both changes the color proportion, and the way the thing is wired up. adjacent subpixels of the same color are driven by the same driver.
Won't this make fonts look even more fuzzy and have more "jaggies"? Why aren't there any 3072x2304 monochrome laptops available? Doesn't anyone else think it's a good goal to have dynamic paper-quality images rather than pixels we are able to casually count?
Hmm, hard to find a definitive source. But, some support for that assertion is here ("10Eh : 320x200 64k-colour (5:6:5)", "111h : 640x480 64k-colour (5:6:5)", ...) and here ("16 bit color depth is supported through several different bit arrangements, including 5-5-5 and 5-6-5.").
Briefly...
It is a really well written desription, it is a shame Design Engineering didn't have an writer that could understand it.
In the printing industry there has been a big trumpetting of a new dot layout
called Hexachrome. This takes the concept of the human eye's propensity
for blurring colors together and adjusts the traditional 3 dot 3 color priniting
layout to 6 dots with a red dot, a blue dot, and 4 different types of yellow/green.
Personally, this looks like a migration from paper to the computer
industry of this same technique which affords more vibrant colors and
cleaner details.
--Ks9
Rearranging the color pixels for color stealing is a reasonable idea, and making blue a little bigger is a nice tweak. Is it worth it? That's difficult to say. Subpixel rendering using color stealing on current LCDs actually does roughly put the extra resolution where you want it for high resolution text--vertical lines are the problem in small text, no horizontal lines.
Okay, I agree that this technology is cool, but I think I would still opt for a traditional LCD display. I'm red-green colorblind, so I am most sensitive to blue, rather than red or green as this display assumes.
I'm surprised that nobody else has posted about colorblindness yet-- I was under the impression that more of us engineering types were affected!
Why do you think blue isn't picked up by your eyes as well? DUH! WAVELENGTH!
Blue does not focus at the same distance as the other colors, by enough of a margin to make excess blue make images seem fuzzy.
The reason the eye is less sensitive to blue is that there are far fewer blue senstive cones than red or green. These blue cones are actually more sensitive to light than the red or green ones, but their deficit in numbers more that conteracts this.
Additionally most blue cones are outside the fovea (the bit of the eye that has the highest density of colour perception cells) so they are thinly spread, and this spread makes the resolution of the blue image poor.
But even this is not the end of the story - the brain does all sorts of visual image processing tricks and the blue signal seems to be amplified to compensate.
Finally the focus bit - blue has a different focus to red and green in the eye, so the image will always be a bit blurred. This is probably the reason why there are so few cones in the fovea - the image would be blurred anyway and your vision would not improve even if you increased the number of cones.
Checking out the linked page, there are explanatory graphics midway down, but they're simply wrong. They show an enlarged letter A, (black on white) then show how that letter is formed on 'stripe' CRTs vs their tile system. The problem is that they have it reversed. They show the color phosphor dots on the black areas and the white areas are still white. The more fundamental difference here is that CRTs are additive, while LCD displays are subtractive, but they don't even go into that.
Worse, they base their assumptions of superiority on the misconception that striped CRT monitors have one trio of RGB stripes for each pixel. They don't even address the triangular RGB phosphor pattern that non-trinitron CRTs use.
In a nutshell, it sounds like a neat idea, but it's no panacea, and looks like it'll have many of the same edge-color problems that current CRTs do (Trinitron and non), only they'll be more obvious on 45deg angles of red and green surfaces, rather than 90deg angles. Take a look at the tile pattern, and see how the pattern does still have stripes, only they're rotated 45degrees right for green and 45 degrees left for red. I imagine a field of 100% blue will, on close inspection, be a thousand little points of light, since each one is surrounded by dark space that takes up 70% of the screen.
Of course, the proof is in the pudding. I wonder when they'll have samples at tradeshows.
Kevin Fox
I note the date on the ClairVoyante web page is 1999. They've had this for a while, and still nothing's coming of it....
i thought its green..
Of the dark hues (RGB), green appears brightest to the eye.
But this article refers to resolution, detail - based on the concentration of blue cones on the retina. A person would have more difficulty reading tiny glowing blue text than green... so there's no point in providing that extra detail.
You probably experienced presbyopia, which is the gradual loss of flexibility in your lenses, thus making near items harder to focus on. This is a normal process that occurs with age.
Admittedly, looking at a monitor all day long can cause eyestrain, especially if you tend toward hyperopia (farsightedness) to begin with. That's my problem: While I can see all right at distances of a couple feet from my face and beyond, my eye muscles have to strain constantly, even when I'm focused at infinity, and working on a computer screen all day every day makes the strain get really bad if I'm not wearing my glasses.
"Biped! Good cranial development. Evidently considerable human ancestry."
No it's not. Do a google search on CLEARTYPE to find pages describing the technique that the Apple ][ was using (Woz == God) and that M$ tried to patent twenty years after.
Do another search, and you'll find the pages where Steve Gibson *retracted* that statement. The Apple II didn't have subpixel rendering. It simply used its pixel generator to create colors on top of a black & white NTSC signal by having a high enough resolution that the bandwidth of the signal crossed over into the area reserved for chroma data.
There's a big difference there.
Try reading the actual ClearType papers too -- there's a LOT of engineering behind ClearType, including the use of conceptual 'perfect' display which is down-transformed to match the actual display, and then reverse-transformed to allow tuning to match the conceptual display as much as possible (ie. with a minimum of signal loss). All heavy signal processing stuff.
Simon
Coming soon - pyrogyra