# YUV values in grayscale images

YUV color space equations are done by:

This leads to:

```
Y=(0.492*B - U)/0.492
Y=(0.877*R - V)/0.877
```

In the case of a grayscale image, `U = V = 0`

. This means (by replacing in the equations above) `Y= R= B`

. What does this means ? That Blue and Red colors are the same ?

yes, in a grayscale image R=G=B (=Y). That's why it's grayscale and not color!

But next time please RTFM or wikipedia or whatever, before filling the forum with basic questions about the YUV color space, which is not related to OpenCV!

!!!HERE!!!@kbarni: He already got the equations and just asked to check his conclusions. I think this is a valid and good question and also of course related to OpenCV.

Sorry I got a bit emotional, but this is the 15th question he's asking in one week about the basics of the YUV color space. He could figure out this thing based on the answers he already got here in the forum.

instead of being angry, may be you can answer to my comment on an answer you gave me @kbarni