[Insight-users] Grayscale to RGB conversion

[Matt Kelsey]

Hello,
I am processing some mammograms and would like a simple way to display
detections and ground truths on a copy of the original scan.  My plan
is to add colored markings to the original grayscale image in the
areas of interest.  I wonder if there is an ITK filter to convert a
grayscale or luminance image to the RGB color space.  The conversion
does not have to be reversible, as the resulting image is for display
only, but I would like the RGB representation of the grayscale scan to
appear as the original (i.e. not a pseudo color mapping).  I see that
there is a filter to convert from RGB to grayscale by combining
different portions of each color component.  This leads me to believe
that a conversion the other way is more complicated then just
assigning each color component the value of the gray tone at that
pixel.
Any insight is appreciated.

Thanks,
Matt Kelsey