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Thread: RGB to RGV : How it is done.

  1. #1
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    Default RGB to RGV : How it is done.

    It's been suggested several times that one could mix a portion of the blue channel into the green channel to virtually enhance the visibility of 405nm. It has also been suggested that this could be done for 445nm too, for those who dislike its deepness.
    This could be done in software or in projector-hardware.
    If you want to implement this, you roughly run into two issues:
    Exactly what percentage is to be mixed into the green channel ?
    What to do if the green channel is already saturated ?

    I did a little reverse engineering and this is how a Particular lasershow-software handles RGV colour mixing :

    The software compares the Blue and Green channel.
    If B is greater than G then 33% of the difference between B and G is added to the Green output-channel. If G is greater than B then both channels are unchanged.

    Code:
    if Bin<Gin then Bout=Bin ; Gout=Gin
    if Bin>Gin then Bout=Bin ; Gout=Gin+0.33(Bin-Gin)

  2. #2
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    Default

    Quote Originally Posted by -bart- View Post
    It's been suggested several times that one could mix a portion of the blue channel into the green channel to virtually enhance the visibility of 405nm. It has also been suggested that this could be done for 445nm too, for those who dislike its deepness.
    This could be done in software or in projector-hardware.
    If you want to implement this, you roughly run into two issues:
    Exactly what percentage is to be mixed into the green channel ?
    What to do if the green channel is already saturated ?

    I did a little reverse engineering and this is how a Particular lasershow-software handles RGV colour mixing :

    The software compares the Blue and Green channel.
    If B is greater than G then 33% of the difference between B and G is added to the Green output-channel. If G is greater than B then both channels are unchanged.

    Code:
    if Bin<Gin then Bout=Bin ; Gout=Gin
    if Bin>Gin then Bout=Bin ; Gout=Gin+0.33(Bin-Gin)
    Hi bart,

    Thanks for sharing your reverse engineering findings with us. Surely this would be better though (using 33% as per your example) as it permits green mixing right up to 100% green input.
    Code:
    Bout = Bin
    Gout = Gin + ((0.33 * Bin) * (100% - Gin%))
    This space for rent.

  3. #3
    mixedgas's Avatar
    mixedgas is online now Creaky Old Award Winning Bastard Technologist
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    Default

    One can also mix 5% of red into the green for useful effects in colors such as facial tones.

    Steve

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