[Tig] Red channel missing
bfriesen at simple.dallas.tx.us
Tue Oct 28 18:49:10 GMT 2008
On Tue, 28 Oct 2008, Bob Friesenhahn wrote:
> This would be a good time to explore the wonders of black/white. Set the red
> channel to a constant value (I recommend 0.2126 of max range if this is sRGB
> or Rec.709, or 0.299 if it is Rec.601 video) and then convert to grayscale.
> Then adjust contrast to suit.
Special purpose software could estimate a red channel based on the
individual pixel values which achieve a median black/white intensity
level. For example, if you had an image of an 18% gray card, then it
should be possible to compute a red channel which provides a fairly
nutural color balance even if colors are not accurate.
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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