Usage #1: 3dThreetoRGB [options] dataset
Usage #2: 3dThreetoRGB [options] dataset1 dataset2 dataset3

Converts 3 sub-bricks of input to an RGB-valued dataset.
* If you have 1 input dataset, then sub-bricks [0..2] are
   used to form the RGB components of the output.
* If you have 3 input datasets, then the [0] sub-brick of
   each is used to form the RGB components, respectively.
* RGB datasets have 3 bytes per voxel, with values ranging
   from 0..255.

  -prefix ppp = Write output into dataset with prefix 'ppp'.
  -scale fac  = Multiply input values by 'fac' before using
                 as RGB [default=1].  If you have floating
                 point inputs in range 0..1, then using
                 '-scale 255' would make a lot of sense.
  -mask mset  = Only output nonzero values where the mask
                 dataset 'mset' is nonzero.
  -fim        = Write result as a 'fim' type dataset.
                 [this is the default]
  -anat       = Write result as a anatomical type dataset.
* Input datasets must be byte-, short-, or float-valued.
* You might calculate the component datasets using 3dcalc.
* You can also create RGB-valued datasets in to3d, using
   2D raw PPM image files as input, or the 3Dr: format.
* RGB fim overlays are transparent in AFNI in voxels where all
   3 bytes are zero - that is, it won't overlay solid black.
* At present, there is limited support for RGB datasets.
   About the only thing you can do is display them in 2D
   slice windows in AFNI.

-- RWCox - April 2002

++ Compile date = Sep 17 2020 {AFNI_20.2.18:linux_ubuntu_16_64}