[MINC-users] Problem with nu_estimate_np_and_em

[minc-users@bic.mni.mcgill.ca]

when I run the following command

nu_estimate_np_and_em -parzen -log -sharpen 0.15 0.01 -iterations 50 -stop 0.01
-shrink 4 -auto_mask -nonotify -b_spline 1 -distance 200 -quiet -execute
-clobber -nokeeptmp manconv_02_t1_final_tmp.mnc /manconv_02_t1_final.imp

I get this message:


Transforming slices:..............................................Done
Error: Composite mask volume is empty.  Check for one of the following:
 1) the user supplied mask is empty (all zeros)
 2) the values within the region of interest are entirely less than one
 3) the user supplied background threshold is too high
 4) the intersection of the various masking options yields an empty mask



I tried changing some of the options in my command but with no luck. I also
noticed someone had a similar problem:
http://www.bic.mni.mcgill.ca/pipermail/minc-users/2002-September/000034.html

Suggestions?

Thanks in advance,

Haytham