> Thanks Volkmar. I'm trying to truncate the image intensity histogram of
> a structural image to improve the contrasts when the original is a bit
It sounds to me like you have images with some bright areas (maybe
scalp, or pulse artefact) which reduce the contrast in tissues you're
interested in, right? Since this is mainly a display problem (and not,
typically, a problem for tissue segmentation) you probably just need
to change the intensity window in the viewer, rather than altering the
Using SPM5's "display" button, change "auto window" to "manual window"
(near the bottom-centre of the graphics window). With "check reg",
right-click the image and choose "image->window" then "local" for the
particular image clicked, or "global" for all images displayed, then
"manual". You can then select lower and upper intensity thresholds.
I'm guessing that your jrs_truncate2.m program clipped the high
intensities to a particular maximum value, you could set the upper
window level to this same value, if you can find it in the code.
Hope that helps,