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Is the 4th Yellow Pixel of Sharp Quattron Hype?
Nom du Keyboard writes "Sharp Aquos brand televisions are making a big deal about their Quattron technology of adding a 4th yellow pixel to their RGB sets. While you can read a glowing review of it here, the engineer in me is skeptical because of how all the source material for this set is produced in 3-color RGB. I also know how just making a picture brighter and saturating the colors a bit can make it more appealing to many viewers over a more accurate rendition – so much for side-by-side comparisons. And I laugh at how you are supposed to see the advantages of 4-color technology in ads on your 3-color sets at home as you watch their commercials. It sounds more like hype to extract a higher profit margin than the next great advance in home television. So is it real?"
To get truly astonishing pictures, they should add a black pixel, to improve contrast.
It strikes me that a better use of a fourth colour pixel would be to represent all those greens the RGB colour space doesn't actually represent.
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And I laugh at how you are supposed to see the advantages of 4-color technology in ads on your 3-color sets at home as you watch their commercials.
Well, I'm not sure if you're correct to laugh at this or not. But all televisions are approximations of something analogue that was captured and in that capturing process, some information was lost. To illustrate, entertain a scenario where I have N standard definition television sets that are displaying footage from standard definition video cameras. I daisy chain them together (each camera directed at the last screen) to record something. As I move from the 0th screen to the Nth screen, I will begin to see degradation as more information is lost and randomness comes into play. The same can be done with HD but since HD captures more information, it can safely be assumed that the sampling and resampling will retain more of the original image.
If you played the Nth HD screen next to the Nth SD screen and piped that through an SD television, you'd still be able to see some difference (for reasonable non-astronomical numbers of N) even though you went through yet another SD television in the end.
I don't know what the fourth color is supposed to buy, I'm unfamiliar with this technology. But the side by side comparison through an SD or HD TV might still be able to demonstrate that the fourth color adds some meaningful information to the image that -- when resampled to be viewed on your device -- suffers less information loss than the three color implementation. Thus successfully demonstrating some superiority. Not showing you precisely what the final product is supposed to be like but instead give you relativity in signal loss and noise.
I also know how just making a picture brighter and saturating the colors a bit can make it more appealing to many viewers over a more accurate rendition
Well, I know that there is a huge photography following that is totally enamored with HDR photography and to many people it makes the images come to life ... I think it's overdone (like autotuning in modern music) but it definitely has a place. Perhaps similarly four color displays hope to widen the dynamic range they can display? I wish I could give you better answers about four color displays but this is the first I've heard of them. Perhaps your questions to a large engineer base are the most effective kind of marketing?
My work here is dung.
Adding an extra phosphor can extend your gamut, increase your dynamic range within your gamut, or give you finer quantization within the gamut, or some combination of all three. The fact that your source material is provided as three quantities (YCbCr, not RGB) doesn't mean four phoshors won't help.
Doesn't mean it will, either.
Like Octarine?
How do you decide which pixel to sacrifice for the colour gambit?
Blar.
Is that supposed to be some kind of joke?
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http://en.wikipedia.org/wiki/Opponent_process
"Kill 'em all and let Root sort 'em out"
Representing yellow with a mix of green and red is already a hack. What's wrong with software determining that the color of a pixel is yellow and actually lighting up a yellow light?
Maybe a yellow light looks more convincing than a red and green light right next to each other. I'd want to see for myself before making blanket judgments.
First, check out http://en.wikipedia.org/wiki/Gamut for reference. The sample gamut picture in the top right shows a typical CRT--lets assume for the sake of argument that LCDs are similar.
If you add a yellow LED to that it just isn't going to add much. The yellow part of the spectrum is already fairly well represented.
*But* if they also change the hue of the green LED toward the blue spectrum then it has a good chance of really opening up the gamut.
The people saying RGB is enough don't understand chromaticity--go look for gamut plots of your favorite output devices and see how little of the full spectrum of colors they can actually reproduce. Printers are especially embarrassing. Your eyes can really see a whole lot of color detail.
There. Now go play some cool javascript games!
Generally speaking, the human eye is less sensitive to blue and most sensitive to red (more yellow, actually) and green. Making sure that the blue pixels are the brightest in the screen and changing the red pixel to something a little more yellow (assuming the firmware adjusts when recreating colors) would probably be the best approaches to catering to the human eye.
Or squant. The time is long overdue for squant support in televisions.
GCHQ Quantum Insert installed. If only our tongues were made of glass, how much more careful we would be when we speak
Right?
/obscure? Hopefully not for the /. crowd...
And the commercials with George Takei (I'm sure there's a "yellow peril" joke in there somewhere) in a white lab coat and the caption reads "actor portrayal" LIKE WE DIDN'T KNOW - IT'S GEORGE FREAKIN' TAKEI YOU IDIOTS!!
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
Obviously, if it was a color that RGB could produce then there wouldn't be any point making a special color channel with it. You should read up on the color gamut and learn a bit about the limitations of RGB.
The red one, just like on Star Trek.
Browsing at +1 - no ACs, I ignore their posts. So refreshing!
"And I laugh at how you are supposed to see the advantages of 4-color technology in ads on your 3-color sets at home as you watch their commercials."
But the script of the commercial is written almost entirely with deference to that fact.
The estimable Mr. Takei tells you, while you're no doubt ogling his adam's apple instead of listening, that he can't actually show you the difference itself, but, "I can show you this," wherupon he looks at the screen and gives his review in a single, somewhat gaudily overacted word.
I'm not sure how anyone misses that, since his behavior is utterly bizarre without the concept of telling-not-showing being in play.
http://regmedia.co.uk/2010/05/07/quattron_4.jpg That just about sums up the entire article.
Not to forget that works for both 50hz and 60hz.
60hz*10=600hz
50hz*12=600hz
A lot of TV sets that use local dimming have a big problem showing starfields. The average color in a starfield is pretty dark, so the LED goes dim and not bright enough to show the stars. It really takes the punch out of Star Wars Special^n Edition if you can't see the stars.
I didn't recognize George Takei at first. Sure he's famous, but he's not William Shatner famous.
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But that assumes the "RGB" sensitivity of our eyes lines up with the emmision spectra of RGB screens; which is not true. Perhaps this Sharp screen brings it closer, actually shows more faithfully the colors which are in the signal; as far as human eye is concerned.
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XYZ space is not perceptually uniform. In particular, the green/cyan area in XYZ occupies a much larger area than would be justified by the eye's ability to distinguish colors in that range. Yellow on the other hand is very under-represented in XYZ.
If you look at the gamuts in a perceptually uniform space such as LUV, you'll find that LCD panels are actually fairly limited in the yellows.
Your talk of efficiency doesn't make sense at all. An LCD uses less electricity than a plasma. It doesn't matter what is hooked up to the display.
True, but the regular LCD color gamut is smaller than the sRGB/Rec 709 gamut that is encoded in the HDTV video standard.
Basically, LCD panels use relatively wide spectrum color filters, so that they don't loos too much light in absorption. The result is a relatively small gamut - smaller than plasma or CRT.
Admittedly one of the problems here is that adding a fourth channel would require a 4-dimensional color space to fully utilize that extra channel. To really utilize this sort of new feature would require a whole new image recording system.
One of the problems facing would-be extensions of the color gamut like adding another color is in part an unlearning of what it means to make a color. In reality, a given color that you see from an object is made up of an entire spectrum from near infrared to ultraviolet (UV-A, to define a "color"), and is a wave function of all possible frequencies along that spectrum.
Somewhere along the way some crude but generally effective simplifications of this philosophy have resulted in things like the YUV and RBG systems, but it should be noted those are 3-dimensional color spaces. Note that the word "dimension" is not in reference to lengths here, but rather representations of the color. Each dimension is merely one more piece of information to display that color.
So whenever you use a 3-dimensional color space, you are reproducing that color spectrum wave function by only selecting three frequencies out of the whole spectrum with which to "broadcast" that information... and you are discarding quite a bit of additional information along the way. This is why color reproduction is quite difficult, and never really gets it "right" in most cases. Try as you might, no possible method of reproducing a color where the information has been discarded can be recreated. Heck, that is basic information theory here too.
Some may counter that a human eye perceives only three colors anyway. Well, that isn't quite true, as there are people with sensitivity to more than three colors (tetra-chromaticity) and of course people who only perceive effectively two or even one color ("color blindness"). Even with all that, not all people perceive the same colors either in the same way, so what may look "good" to one person may look "awful" to somebody else. What it all boils down to is that to really do a proper representation of the color, it really is vitally important to completely and accurately reproduce that entire wave function which represents all possible frequencies.
Think of it more this way, perhaps. Imagine if you were listening to some music, but the recording medium only reproduced the songs with three frequencies for playback. It would be some rather boring music. BTW, it is possible to "sample" light in the same manner that sound is sampled to give a more accurate reproduction of a color, but that would be an insane amount of data as the sampling frequency would have to be on the same order as the frequency of the light.... actually a higher rate of sampling to be precise.
One of the really nice things about light from an incandescent light bulb is that it is spread out over nearly the entire frequency spectrum. Traditional film projectors take advantage of that fact and when color film is shown in front of that light bulb, the frequency spread of various color layers on the film tend to smooth out with each other and generate that continuous spectrum. It still isn't perfect and color film still has only three channels (usually) but at least an attempt to re-create that whole frequency spectrum is there. Also note that different film manufacturers have a frequency response that is sometimes different, which is why some film manufacturers are preferred over others and certainly impacts the film making process in some subtle but interesting ways.
For LCD screens and worse yet for LED systems, the frequency curve isn't nearly so good. If you would look at it with a diffraction grating or prism that separates the colors out, you would see some sharp lines rather than a continuous spectrum. That is where the real problem lies with LCD panels and why color accuracy is not very good. Certainly adding a yellow line to that curve would generally help to smooth out that spectrum or at least add some more visual information, even if that color information isn't being directly recorded by the storage medium.