i.rgb.his is an image processing program that processes three input images as red, green, and blue components and produces three output images representing the hue, intensity, and saturation color properties.
The output images base upon a standard red-green-blue (rgb) to hue-intensity-saturation (his) color space transformation. Hue ranges in degrees [0, 360] while intensity and saturation range in [0, 1].
The module supports various bits per image (as in bits per color channel, bitness ranging in [2,16]).
It is possible to process three bands with i.rgb.his and recover the original bands, nearly identical, with i.his.rgb. Due to rounding, minor loss of precision is expected. Cell values will be reproduced exactly after transformation in both directions, within plus or minus 1.
Each output raster map layer is given a linear gray scale color table. The current geographic region definition and mask settings are respected.