[MINC-users] mincaverage behaviour

[Johnathon Walls]

   Hello,
   I am running across some unexpected behaviour for mincaverage using
   -normalize and I'm not sure if it's a bug or not.
   Description:
   mincaverage -normalize in1.mnc in2.mnc in3.mnc out.mnc
   results in out.mnc with all zeros if the input files have a mean less
   than zero.
   I can reproduce this every time.
   At the moment I am able to 'hack' my minc files by adding a constant so
   that they all have means > 0.
   I think perhaps the issue might lie in lines 533-561 here:
   [1]https://github.com/BIC-MNI/minc/blob/master/progs/mincaverage/mincav
   erage.c
   Where vol_mean[ifile] is included in the determination of vol_total and
   global_mean (lines 537 and 554), but the value of
   average_data.norm_factor[ifile] is conditional upon the vol_mean[ifile]
   being > 0 (otherwise, the norm_factor[ifile] is set to 0.0).
   Any ideas if this is a bug (though perhaps not in the lines that I am
   suggesting) or a design decision?  If it's a design decision, can I ask
   the reasoning? (Maybe I'm not understanding the meaning of world values
   in minc files?)
   Thanks
   Johnathon
   --
   Johnathon R. Walls, PhD
   Scientist - Therapeutic Target Discovery
   Regeneron Pharmaceuticals
   777 Old Saw Mill River Road
   Tarrytown, NY USA 10591-6707
   Phone: 914.847.3006 Fax: 914.847.7544
   Email: johnathon.walls at regeneron.com

   This e-mail and any attachment hereto, is intended only for use by the
   addressee(s) named above and may contain legally privileged and/or
   confidential information. If you are not the intended recipient of this
   e-mail, any dissemination, distribution or copying of this email, or
   any attachment hereto, is strictly prohibited. If you receive this
   email in error please immediately notify me by return electronic mail
   and permanently delete this email and any attachment hereto, any copy
   of this e-mail and of any such attachment, and any printout thereof.
   Finally, please note that only authorized representatives of Regeneron
   Pharmaceuticals, Inc. have the power and authority to enter into
   business dealings with any third party.

References

   1. https://github.com/BIC-MNI/minc/blob/master/progs/mincaverage/mincaverage.c