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Re: YUV/RGB Color Space Issues

On Dec 18,  1:33pm, Pete Mountanos wrote:
> Subject: RE: YUV/RGB Color Space Issues

> 1.	RGB space is "larger" than YUV space.  Consider it a cube.  YUV can
> be considered a rectangular shaped box inside YUV rotated around so that it
> projects a hectagon in 2-D space.
> 2.	If you then reduce the levels of the big box so it fits "inside" the
> smaller YUV box you get a much smaller cube.

	If you've limited RGB color space to only positive values then it is
indeed a much smaller space than YUV - consider the cases of 0% and 100% luma.
It is simple to add chroma to a 0 or 100 luma YUV signal but impossible with
RGB - black is RGB value 0:0:0, since chroma is derived from a DIFFERENCE
between RGB components the allowable chroma amplitude decreases as you near 0
or 100 luma.

Rich Torpey

thanks to Neil Kempt for support of the TIG in 1998
TIG subscriber count is 910 on Thu Dec 18 13:04:47 PST 1997
complete information on the TIG website http://www.alegria.com/tig3/