

i.rgb.his - 

i.rgb.his is an image processing program that processes three input
\raster\ \map layers\ as red, green and blue components and produces
three output raster map layers representing the hue, intensity and
saturation of the data.  The output map layers are created by a
standard red-green-blue (rgb) to hue-intensity-saturation (his) color
transformation.  Each output map layer is given a linear grey scale
color table.

Manual entry for \i.rgb.his\
