[MINC-users] mincresample along a dimension with *-width variables

[Andrew Wood]

Are they ever used for spatial dimensions? It was actually a mistake that
it ended up in my affected volumes.


On Thu, Feb 6, 2014 at 12:31 PM, Vladimir S. FONOV <vladimir.fonov at gmail.com
> wrote:

> I've seen them used in dynamic acquisition where they are used with
> time dimension, for example in PET data
>
> On Thu, Feb 6, 2014 at 12:25 PM, Andrew Wood <andrew at biospective.com>
> wrote:
> > HI All,
> >
> > I ran into a issue when resampling a volume along a dimension which has
> > *-width attribute values. It seems that such a dimension can't be
> resampled
> > to have a different number of elements.
> >
> > An example input volume:
> > $ mincinfo in.mnc
> > file: in.mnc
> > image: signed__ short -32768 to 32767
> > image dimensions: zspace yspace xspace
> >     dimension name         length         step        start
> >     --------------         ------         ----        -----
> >     zspace                     47        3.375     -1027.16
> >     yspace                    128     -2.65336      363.575
> >     xspace                    128     -2.65336      171.012
> >
> > $ mincheader in.mnc | grep zspace-width
> >         double zspace-width(zspace) ;
> >                 zspace-width:dimorder = "zspace" ;
> >                 zspace-width:varid = "MINC standard variable" ;
> >                 zspace-width:vartype = "dim-width____" ;
> >                 zspace-width:version = "MINC Version    1.0" ;
> >                 zspace-width:filtertype = "square____" ;
> >                 zspace-width:spacing = "regular__" ;
> >                 zspace-width:width = -3.375 ;
> >  zspace-width = -3.375, -3.375, -3.375, -3.375, -3.375, -3.375, -3.375,
> >
> > Now, add a voxel to each dimension:
> > $ mincresample -clobber in.mnc out.mnc -nelements 129 129 48
> > (from miattputstr): Function 'dimrename' not implemented
> >
> > $ mincinfo out.mnc
> > file: out.mnc
> > image: signed__ short -32768 to 32767
> > image dimensions: zspace yspace xspace
> >     dimension name         length         step        start
> >     --------------         ------         ----        -----
> >     zspace                     47        3.375     -1027.16
> >     yspace                    129     -2.65336      363.575
> >     xspace                    129     -2.65336      171.012
> >
> >
> > I dug around the mincresample source code, and the the first thing done
> > when creating the output volume is a copy of all variable definitions
> from
> > the input, excluding {x,y,z}space, image, and image-{min,max}. It appears
> > that copying the zspace-width actually forces zspace to be copied,
> > resulting in a naming conflict between the original zspace and our new
> > zspace. To work around this, it tries to rename the copied zspace to
> > zspace0, which is where we see the "Function 'dimrename' not implemented"
> > error message. The result is being stuck with the size of the original
> > zspace.
> >
> > The problem goes away if {x,y,z}space-width is added to the exclusion
> list
> > for the original variable copy operation. I'm having trouble imagining
> when
> > those *-width variables are used though, so I'm not sure if this'd be a
> > sane fix.
> >
> > Does anyone have any thoughts that might clear up this situation?
> >
> > Thanks,
> > Andrew
> > _______________________________________________
> > MINC-users at bic.mni.mcgill.ca
> > http://www.bic.mni.mcgill.ca/mailman/listinfo/minc-users
>
>
>
> --
> Best regards,
>
>  Vladimir S. Fonov ~ vladimir <dot> fonov <at> gmail <dot> com
> _______________________________________________
> MINC-users at bic.mni.mcgill.ca
> http://www.bic.mni.mcgill.ca/mailman/listinfo/minc-users
>