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Figure 10: Slice of glyphs

This requires an actual DT-MRI dataset, which is available online. The following commmand creates a single slice that will be visualized:

unu resample -i ../gk2-rcc-mask.nhdr \
   -s = x0.75 x0.75 x0.75 -k cubic:1,0 \
 | tend slice -a 2 -p 57 -o slice-small.nrrd

Then "tend glyph" is used to make the rendering. You may want to decrease the image sizes (down from 1700x1700) as this ray-tracer is not currently multi-threaded.

setenv FR "0 0 10"
setenv UP "0 -1 0"

echo "1 1 1 1 -1 -1 -4" \
 | emap -i - -amb 0 0 0 -fr $FR -up $UP -rh -o - \
 | unu 2op ^ - 1.7 \
 | unu 2op - 1 - \
 | unu 2op x - 3.14159 \
 | unu 1op cos \
 | unu 2op + - 1 \
 | unu 2op / - 2 -o emap.nrrd

alias GLYPH tend glyph -rt -a fa -atr 0.0 -ctr 0.999 \
   -slc 2 0 -sg -1.9 -off -1.5 \
   -fr $FR -up $UP -rh -or -ur 0.06 0.33 -vr 0.34 0.61 \
   -am 1.0 -ga fa -sat 0.0 -emap emap.nrrd -gam 1.0 -bg 0 0 0 \
   -is 1700 1700 -ns 4 -o -

tend evalclamp -i slice-small.nrrd -min 0.05 \
 | GLYPH -g sph -gsc 0.0035 -o - \
 | unu slice -a 0 -p 0 \
 | unu gamma -g 0.92 \
 | unu quantize -b 8 -min 0 -max 1 -o slice-sph.png

tend evalclamp -i slice-small.nrrd -min 0.05 \
 | GLYPH -g sqd -gsc 0.0030 -o - \
 | unu slice -a 0 -p 0 \
 | unu gamma -g 0.92 \
 | unu quantize -b 8 -min 0 -max 1 -o slice-sqd.png

rm -f emap.nrrd

unu resample -i slice-sph.png -s 300 300 -o _slice-sph.png
unu resample -i slice-sqd.png -s 300 300 -o _slice-sqd.png
unu resample -i slice-sph.png -s 100 100 -o __slice-sph.png
unu resample -i slice-sqd.png -s 100 100 -o __slice-sqd.png