Why channel decorrelation can improve compression?

Hi,

I am trying to understand why channel decorrelation can improve
compression in RGB24 images. Why in general (G, R-G, B-G) would
compress better than (R,G,B)? Can you suggest me any book/web site
where I can read about this?

Thank you for help.

>
Sure. option is the RCT of JPEG2000 which uses better "color
weights", namely
>
(r + 2g + b) / 4 *-y
>
b - y -cb
>
r - y -cr
>


This one works far better than (G, R-G, B-G) for my algorithm. Do you
think I can use it without patent issues?

Thank you for help :-P

>
Yes, to my very knowledge, this one is not only licence-fee-free, but also
licence free (I would be astonished if someone could patent this).
>

GREAT! My little garage-spare-time-coded compression algorithm is
getting very very close to JPEG-LS compression level with this :-PP

>
If so, please compare yours with JPEG-LS equipped with RCT to have an apples to
apples comparison.
>

Yes, this is what i did. I can see that using (G, R-G, B-G) or
JPEG2000 RCT before JPEG-LS doesn't effect very much JPEG-LS
compression (I am using JPEG-LS Photoshop plug-in from HP, as it let
you choose the RCT you want in a pool of 5-6.
Instead for my algorithm it seems to be more effective. I have to do
more testing but it seems to be a great improvement in my case. Hope
no errors somewhere :-P

This one works far better than (G, R-G, B-G) for my algorithm.


Yes, of corse it is no more lossless, as sayd below :-(