Abhinay Joshi wrote:
> Could anyone please help me understand the term 'ACTC' which is
> colormap? what's does it excatly mean?
See "doc colormap" in Matlab. Basically, colormaps decide how values
(such as t-values, MRI intensities, segmentation probabilities, etc.)
show up on your screen.
The most common Matlab colormaps are jet (a kind of blueish-redish
spectrum, which gets its name from being originally developed for
fluid flow/jet visualisation; and its popularity from making dull
images look exciting ;-) ) and grey (higher values are brighter shades).
actc appears to be Matthew Brett's "activation" colormap, see:
http://imaging.mrc-cbu.cam.ac.uk/imaging/DisplaySlices
and
[log in to unmask]" target="_blank">http:[log in to unmask]
as you can see from the first link, actc is a kind of blueish-redish
spectrum, probably developed with the same goal as jet (!)
Personally, I don't like these exciting all-around-the-spectrum
colormaps (which have slightly blueish-green and slightly
reddish-yellow looking kind of similar(ish), but on different sides of
zero). I would prefer a simpler straight line through the colour
wheel, like cyan-black-red, but with so many list subscribers studying
perception/vision/psychology I wouldn't dare to claim that this would
look perceptually better...
Yours,
Ged.
P.S. It's lucky SPM5 is so slow, otherwise I'd never have time to
write all this... (just kidding)
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