Q:Hi, I’d like to display a volume using a color lookup table other than the usual spectral,hotmetal etc that are offered in Display. In Display I found: Colour Coding (D) → UserDefColCode (Q) but it only changes the color map to grey and doesn’t prompt for a custom lookup table. Is there another way to use this ‘feature’?

Alternatively, I think I can use minclookup with the -lookup_table option, and despite the excellent information here: http://wiki.bic.mni.mcgill.ca/index.php/MinclookupManPage I still need some help creating the right lookup table. I found this in minclookup.c:

static double spectral_lookup_values[] = {

  0.00, 0.0000,0.0000,0.0000,
   0.05, 0.4667,0.0000,0.5333,
   0.10, 0.5333,0.0000,0.6000,
   0.15, 0.0000,0.0000,0.6667,
   0.20, 0.0000,0.0000,0.8667,
   0.25, 0.0000,0.4667,0.8667,
   0.30, 0.0000,0.6000,0.8667,
   0.35, 0.0000,0.6667,0.6667,
   0.40, 0.0000,0.6667,0.5333,
   0.45, 0.0000,0.6000,0.0000,
   0.50, 0.0000,0.7333,0.0000,
   0.55, 0.0000,0.8667,0.0000,
   0.60, 0.0000,1.0000,0.0000,
   0.65, 0.7333,1.0000,0.0000,
   0.70, 0.9333,0.9333,0.0000,
   0.75, 1.0000,0.8000,0.0000,
   0.80, 1.0000,0.6000,0.0000,
   0.85, 1.0000,0.0000,0.0000,
   0.90, 0.8667,0.0000,0.0000,
   0.95, 0.8000,0.0000,0.0000,
   1.00, 0.8000,0.8000,0.8000
};

I’m guessing the last three columns are RGB values. Is there an algorithm out there that will spit out the incremental RGB values between two (or more) colors? Does anyone have some custom lookup tables they’ve created and would be willing to share?

Ideally, it would be nice to use the rgb color maps already defined and part of the brain-view package (on my machine are here: /usr/local/bic/share/brain-view). http://www.bic.mni.mcgill.ca/pipermail/minc-users/2010-February/002637.html

A: Alternatively, I think I can use minclookup with the -lookup_table option, and despite the excellent information here: Does anyone have some custom lookup tables they’ve created and would be willing to share?

Yes:

spencer:~$ cat lib/luts/bluered
0.000 0.8 0.8 1.0
0.125 0.4 0.8 1.0
0.250 0.0 0.4 1.0
0.375 0.0 0.0 0.5
0.500 0.0 0.0 0.0
0.625 0.5 0.0 0.0
0.750 1.0 0.4 0.0
0.825 1.0 0.8 0.4
1.000 1.0 0.8 0.8
That what you are after?

The first column is the vector value (scaled between 0 and 1) and the last three are the RGB values.