Infoseite // Color Farmodell in YUV or YPbPr and YCbCr

Frage von Blackeagle123:


Hello,

I have an image for you, which will describe how from YUV to RGB values can be calculated.

zum Bild

There are, however, synonymous sg YPbPr and YCbCr. How exactly does YUV of the two?
How can I change the values Pb and Pr, Cb and Cr, or understand? (This is I think necessary for the calculation in RGB to understand) And why is the Y luminance values of three?

Danke schon mal für eure Hilfe!

Liebe Grüße,
Constantin



Antwort von Blackeagle123:

Picture einer UV-Tabelle, with Y-Wert of 0,5.

Hier ein Image, was eine UV-Tabelle zeigt and das Problem annähernd für YUV verständlich macht. Jedoch macht das für mich nur Sinn, wenn jeder Variablenwert (Y, U and V) aus exactly one value exists.

Greetings again,
Constantin



Antwort von roller247:

I know with me, not color, but the formula looks like a normal matrix multiplication.
If in fact the notation for a matrix multiplication, then there are Y, Pb and Pr only consist of exactly one value. Is your problem perhaps that you do not understand the multiplication?
Is explained here:




Antwort von Blackeagle123:

Hey,

Thanks for the matrix as far as I then understood.
Maybe someone can point s.der explain exactly wiesofür Y holds:

Y '= 0.299 * R + 0.587 * G +0.114 * B'

Is it true that you simply YUV can understand that one has a table for U and V, for each U-and V-value of a certain color set, and Y, only the brightness determined? What is working with YUV and not always with RGB, or television with CMY (cyan, magenta, yellow)?
Why are there so many different ways to describe color? It is still HSL, HSB HSI ... RGB, CMY, YUV, ...

Many greetings,
Constantin



Antwort von Quadruplex:

"Blackeagle123" wrote: Hey,

Thanks for the matrix as far as I then understood.
Maybe someone can point s.der explain exactly wiesofür Y holds:

Y '= 0.299 * R + 0.587 * G +0.114 * B'
That all comes from Buntfernsehen :-)

If you're black and RGB compatible bandwidth saving and transferring want's you have to convert.

Your camera makes internal RGB, RGB to the screen. For the transmission / storage is RGB from Y (ie the black and white signal) to the above formula. The percentages are by practical research (and the underlying physics) revealed: Mach times from a Still Image with all shades and a black and white image to an R-, G-and B-extract. Then you will find that the green image to the black screen comes s.nächsten. The percentages for the colors correspond to the correct proportion of the respective spectra s.einem monochrome image.

Reading: "Everything on television, cable, satellite" of still unspeakable Jean Pütz - sold out and only needed / in the library to find.



Antwort von Blackeagle123:

Hey,

The question was why the television is not synonymous in RGB can count, but in YUV. Or in general, why are so many different formats exist. (above!)

Many greetings,
Constantin



Antwort von hannes:

YCbCr Is Digital
MPEG compression, which is used in DVDs, digital TV and video CDs, is coded in YCbCr, and digital camcorders (MiniDV, DV, Digital Betacam, etc.) output YCbCr over a digital link such s.FireWire or SDI. The ITU-R BT.601 international standard for digital video defines both YCbCr and RGB color spaces. See YCbCr sampling.

Is Analog YPbPr
YPbPr is the analog counterpart of YCbCr. It uses three cables for connection, whereas YCbCr uses only a single cable (see YPbPr). See YUV, YUV / RGB conversion formulas and ITU-R BT.601.



Antwort von Quadruplex:

"Blackeagle123" wrote: The question was why the television is not synonymous in RGB reckon kannoben mentioned!)
Can he - through scart.
"Blackeagle123" wrote: Or in general, why are so many different formats exist.
Because RGB is an unwieldy format. YUV and his relatives have been developed for color images (ie RGB information) to save space / black compatible to send (above).

That is the short version. The reading of the book mentioned and other web search, I can not save you - you can really relating to (see Pütz Schang) Books to write.



Antwort von Blackeagle123:

Wow, thank you:)

Hat mir gut helpful!

Can you now explain to me what the format HSL, HSB, HSI, ... needs?

Many greetings,
Constantin






Antwort von TheBubble:

"Quadruplex" wrote:
Because RGB is an unwieldy format. YUV and his relatives have been developed for color images (ie RGB information) to save space / black compatible to send (above).


A picture in YUV colorspace with whatever color per pixel requires not just less memory than a picture in RGB color space. Only through a smaller sampling of the Cr and Cb (or U and V) components will reduce the amount of information, but the image quality synonymous. It is just not so, as if in RGB Frabraum for example, the R and B components with a smaller component of the G Resolutionals would save.