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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?"
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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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.
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.
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.
http://regmedia.co.uk/2010/05/07/quattron_4.jpg That just about sums up the entire article.
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.
One that hath name thou can not otter
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.
HDR is something which enables photographers to approach the dynamic range available in print photography while largely retaining the color saturation and other qualities of transparency film
That doesn't make much sense, because transparencies and computer displays have a higher dynamic range than prints, not lower.
I reality, HDR photography is about capturing a scene that has a very high contrast ration, beyond what cameras can capture or monitors display. It is done by using shots with different exposures, so parts of the image that would otherwise be over or under-exposed retain detail and don't just get clipped or blown out.
It does tend to be overdone, but so is saturation and the colors that people use in their photos/video don't particularly reflect reality very well either.
Actually, HDR photos are often a better representation of reality, because the human eye adjusts to different brightness levels, which is what the HDR process is doing.
... and then they built the supercollider.
Fechner color
is an illusion of color seen when looking at certain rapidly changing or moving black-and-white patterns. They are also called pattern induced flicker colors (PIFCs). Not everyone sees the same colors.