## Colours

###### posted 11 years ago by Ben Cordero

I didn't know this before, but there is a colour space that is more appropriate to use for human viewing than RGB.

YUV is made up of 3 components, but instead of mixes of the colours red, green and blue, it is composed of a luminescence value, and two chroma. Encoding in such a way can provide better transmission of pictures for human viewing than using the proportions of RGB.

Translating between the two is simple as $latex \left(\begin{array}{c}Y'\\U\ \V\end{array}\right)=\left(\begin{array}{ccc}0.299&0.587&0.114\\-0.14713&-0. 28886&0.436\\ 0.615 & -0.51499 & -0.10001 \end{array}\right)\left(\begin{array}{c}R\\G\\B\end{array}\right)$ And the inverse $latex \left(\begin{array}{c}R\\G\\B\end{array}\right)=\left(\begin{ array}{ccc}1&0&1.13983\\1&-0.39465&-0.58060\\ 1 & 2.03211 & 0 \end{array}\right)\left(\begin{array}{c}Y'\\U\\V\end{array}\right)$ So, how does this make transmission of pictures better? The eye is typically most sensitive to brightness changes, which is recorded at the Y value. The U and V values stores information about colour. Most of this information can be thrown away. But wait, "Hold on, there's a Y' in the equations above, not a Y. You're just trying to confuse me." I hear you whine. Y refers to the quantity of light needed. However, what is more appropriate to encode is the electrical voltage/signal amplitude, Y', needed to generate Y that we see.