I'm not entirely sure what you want to do, or how your previous attempt failed, but maybe try '0 - i1' as the equation. Although I would've guessed '-i1' should work.
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From: SPM (Statistical Parametric Mapping) [[log in to unmask]] on behalf of Yann [[log in to unmask]]
Sent: Tuesday, July 10, 2012 10:14 PM
To: [log in to unmask]
Subject: [SPM] Change sign of an image
Dear SPMers,
I would like to inverse the sign of an image using ImCalc, but I am not sure if I am right.
The goal is to give a negative value to the activation clusters of this image.
I tried the function f = '-(i1)' and the result in MRIcroN looks like there is a value now for all that was not an activation cluster ... and 'nothing' for my precedent cluster (looks like 'emplty') and does not tell me if the value of my original cluster is now negative. I am joining an image: red clusters are my 'original activation clusters' and in blue is what ImCalc gave me.
Any idea/ experience in that kind of operation?
Thanks in advance, any help will be highly appreciated!
Cheers,
Yann
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